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Thread: My journey to Evohome and a New Worcester Bosch Boiler

  1. #1
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    Default My journey to Evohome and a New Worcester Bosch Boiler

    Thank You for the posts on this site for helping me resolve some Evohome configuration questions. Once you know the answers, it seems so easy - but not before. I hope my story and experiences below will be helpful to future visitors.

    Phase 1, The Legacy System!
    My original installation had mechanical Thermostatic Radiator Valves (TRVs) on nearly all radiators and a single thermostat on the hall wall. When the thermostat called for heat, the Central Heating (CH) pump started and all rooms went to their set temperature, unless the hall heated first and the thermostat turned off the CH pump!

    Thanks to an article in PC Pro by a certain Paul Ockenden (thank you Paul!) , I converted the system to Evohome (EH). The TRVs were replaced with EH HR92 Radiator Controllers and an EH Wireless Relay Box (BDR91) was connected to the boiler in place of the wires from the hall thermostat. The BDR91 was paired to the ‘Boiler Control’ on the EH controller. Since the BDR91 was playing the role of CH thermostat, this configuration worked perfectly, and the EH 'Boiler Control' parameters were available to fine tune the configuration.

    Phase 2, A new Boiler.
    When the old boiler failed, I replaced it with a Worcester Bosch 8000 Life Regular Boiler and a Greenstore unvented Hot Water tank. The installation was performed to an S plan configuration, with one pump and two motorised valves. The ‘old’ BDR91 was to be re-tasked to the Central Heating and an EH Hot Water kit (ATF500DHW) was acquired, which contained a Wireless Cylinder Thermostat Transceiver (CS92) and a second BDR91.

    I think it is fair to say that the EH installation manual is a little light when it comes to understanding – and the wording in the Guided Configuration on the EH controller gives rise to further confusion! The Guided Configuration refers to ‘Stored Hot Water Configuration’, which implies that the other option must relate to heating – this is NOT the case! The Stored Hot Water configuration option will allow you to configure the Hot Water Sensor (CS92) and BOTH BDR91s controlling the motorised valves for Hot Water and Central Heating. The confusion continues when you look at ‘System Devices’ on the EH Controller and see that there is an option for Stored Hot Water and Boiler Control!

    As I had previously controlled the heating in phase 1 through the ‘boiler control’ (emulating the thermostat), it took research on this forum to understand the ‘new paradigm’. The motorised valves contain an electrical connection to the boiler that activates the boiler when the valve is open. Therefore, once either valve opens (due to CH or HW heat demand), the boiler will be fired. In this ‘S’ plan model there is no need for ‘boiler control’ – it is built in via the valves. So, to convert my system to S Plan, I had to 1) Set boiler control to NONE (ie remove the phase 1 use of boiler control) 2) Reset/Initialise the pairing on the BDR91s (press and hold the button until it fast blinks red) and then 3) Run the Stored Hot Water Configuration option, which paired the Hot Water Sensor, then the HW BDR91 and then the CH BDR91. A quick test and all was working.

    Beyond Phase 2 – When Worcester Bosch (WB) and EH do not play well together!
    It took a few weeks to work this out, but….

    As the ‘heating season’ got going, EH controlled the zones, progressively closing the HR92s in a zone as the zone reached its target temperature. From running the CH 100% of the time when there was a cold zone, once all zones were near their target setpoint (and hence all HR92s were partially closed), EH started to ‘cycle’ the CH BDR91 at regular intervals and for short periods of time. Meanwhile, the WB boiler went through its own ‘shut down cycle’ whenever the CH BDR91 turned off and so was actually still running for a couple of minutes after EH thought it was turned off. In practice there could be only 1-2 minutes between the boiler shutting down and the next cycle starting. I was seeing the boiler ‘come alive’ at the start of each cycle, but the burners did not show as lit. Out flow temperature dropped to below 30C and hence the radiators were all but cold and as a result, zone temperatures started to fall from their setpoint. It was only when the zones dropped well below their setpoints, that EH ran the CH BDR91 for longer periods of time and at that point the burners fired.

    Those in the know, will recognise the EH behaviour as TPI (Time Proportional & Integral). The problem is that Honeywell confirmed that there is no way to control this behaviour – there are no ‘cycles per hour’ or ‘minimum run time’ parameters available outside of ‘boiler control’ – which was no longer in use. It seemed that there was intelligent software in the WB boiler which was not playing well with this constant short cycling!

    Maybe OpenTherm was the answer? EH has an OpenTherm bridge, but WB uses EMS. WB also has an OpenTherm bridge in their EasyControl range, but this is to allow their EasyControl range to talk to an OpenTherm boiler and not the other way around. WB technical support told me:

    “Worcester boilers do not support the Open-therm protocol as the Worcester controls operate using an EMS protocol. We would not be able to support an interface that converts from Open -therm to EMS as these would not have been tested with the products. Third party controls would only be supported if operating the boiler via a 230vac switched demand.”

    I contacted the Evohome shop (a great and friendly company who supplied my EH solution) and their support told me that IF every radiator had an HR92 fitted (a fully zoned solution), I should not have installed a motorised valve for the heating circuit, only for the HW, and then relied on the HR92s to prevent flow around the heating circuit. In this model, the CH BDR91 would have been installed as a boiler control – giving me access to the EH parameters I needed.

    Phase 3 – The Final Solutions
    I needed to find a way to make the WB less sensitive to ‘short burn cycles’ and to get access to the relevant parameters within EH – and hopefully without any plumbing changes! I therefore changed the EH configuration again:

    First, I cleared the EH/BDR91 config and reran the Guided Configuration as a Stored Hot Water only system – this paired only the CS92 and the HW BDR91. I then manually paired the CH BDR91 as a Boiler Controller.

    Rather than change the wiring, the CH BDR91 still operates the CH motorised valve and therefore triggers the boiler through the existing wiring from that valve. This means that when there is CH demand, the CH valve opens and the boiler fires. When there is HW demand, BOTH valves open.

    At first glance, this looks wrong, but in practice this is the same as if the CH valve had been removed and the CH BDR91 connected to the boiler directly! So long as all the HR92s are closed (Zone up to temperature/low setpoint/heating off), there will be no flow around the CH plumbing – hence the CH valve is effectively acting as the bridge to the boiler controller.

    Now that I have the CH BDR91 defined as Boiler Control, I have access to the EH ‘cycles per hour’ and ‘minimum run time’ parameters!

    The largest value for the EH ‘minimum run time’ is 5 minutes – which is now set. On the WB side, there is a parameter called ‘Standby Time’ which controls the ‘Anti Cycle Mode’ (option 3-b2 for the record). The default is 5 minutes – which explains why the burners never fired in the phase 2 scenario! By reducing this to 3 minutes (and with the EH minimum run time set to 5 minutes), the burners are now running on every cycle.

    So far, phase 3 is delivering the goods and remains the current configuration!

    In Closing
    For anyone who has an EH solution and a need to install a modern (non Opentherm) boiler, I hope there are some ideas in here which will help the ‘clever’ software on both sides play better together! Of course, there may be a much better solution..

    I am still open to a means to bridge EH to WB’s boiler control more intelligently (OpenTherm to EMS? EH to EasyControl bridge?), provided that this would not invalidate the multi-year manufacturer warranty offered by WB.

    Phase 3 seems to be a fine end point, but is anyone able to offer a suggestion for Phase 4?

  2. #2
    Automated Home Ninja
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    A partial solution to Phase 4 which you may already be aware of is the 'Nefit EMS-OT OpenTherm converter' described on this page:

    https://myboiler.com/opentherm/worce...sch-opentherm/

    It's only a partial solution as I can't comment on any potential impact on the WB warranty. I think another user has tried this with their WB boiler, but wasn't impressed with the outcome and reverted back to the original controls

    https://www.automatedhome.co.uk/vbul...-maybe-Evohome

    I've done something similar with my Glow Worm boiler and added an Opentherm interface as the boiler only supported either Glow Worm's 'smart' controls or a standard on/off RT connection. I ran my Evohome system for a couple of years via the RT connection and it worked really well. However, adding the Opentherm interface earlier this year now allows control of the boiler via the Honeywell R8810 Opentherm bridge and I'm pleased with the outcome and temperature control is improved within each zone (confirmed by extensive obsessive monitoring ) and I've not had any concerns about the boiler firing/gas usage.

  3. #3
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    Quote Originally Posted by PRBUK View Post
    Thank You for the posts on this site for helping me resolve some Evohome configuration questions. Once you know the answers, it seems so easy - but not before. I hope my story and experiences below will be helpful to future visitors.

    Phase 1, The Legacy System!
    My original installation had mechanical Thermostatic Radiator Valves (TRVs) on nearly all radiators and a single thermostat on the hall wall. When the thermostat called for heat, the Central Heating (CH) pump started and all rooms went to their set temperature, unless the hall heated first and the thermostat turned off the CH pump!

    Thanks to an article in PC Pro by a certain Paul Ockenden (thank you Paul!) , I converted the system to Evohome (EH). The TRVs were replaced with EH HR92 Radiator Controllers and an EH Wireless Relay Box (BDR91) was connected to the boiler in place of the wires from the hall thermostat. The BDR91 was paired to the ‘Boiler Control’ on the EH controller. Since the BDR91 was playing the role of CH thermostat, this configuration worked perfectly, and the EH 'Boiler Control' parameters were available to fine tune the configuration.

    Phase 2, A new Boiler.
    When the old boiler failed, I replaced it with a Worcester Bosch 8000 Life Regular Boiler and a Greenstore unvented Hot Water tank. The installation was performed to an S plan configuration, with one pump and two motorised valves. The ‘old’ BDR91 was to be re-tasked to the Central Heating and an EH Hot Water kit (ATF500DHW) was acquired, which contained a Wireless Cylinder Thermostat Transceiver (CS92) and a second BDR91.

    I think it is fair to say that the EH installation manual is a little light when it comes to understanding – and the wording in the Guided Configuration on the EH controller gives rise to further confusion! The Guided Configuration refers to ‘Stored Hot Water Configuration’, which implies that the other option must relate to heating – this is NOT the case! The Stored Hot Water configuration option will allow you to configure the Hot Water Sensor (CS92) and BOTH BDR91s controlling the motorised valves for Hot Water and Central Heating. The confusion continues when you look at ‘System Devices’ on the EH Controller and see that there is an option for Stored Hot Water and Boiler Control!

    As I had previously controlled the heating in phase 1 through the ‘boiler control’ (emulating the thermostat), it took research on this forum to understand the ‘new paradigm’. The motorised valves contain an electrical connection to the boiler that activates the boiler when the valve is open. Therefore, once either valve opens (due to CH or HW heat demand), the boiler will be fired. In this ‘S’ plan model there is no need for ‘boiler control’ – it is built in via the valves. So, to convert my system to S Plan, I had to 1) Set boiler control to NONE (ie remove the phase 1 use of boiler control) 2) Reset/Initialise the pairing on the BDR91s (press and hold the button until it fast blinks red) and then 3) Run the Stored Hot Water Configuration option, which paired the Hot Water Sensor, then the HW BDR91 and then the CH BDR91. A quick test and all was working.

    Beyond Phase 2 – When Worcester Bosch (WB) and EH do not play well together!
    It took a few weeks to work this out, but….

    As the ‘heating season’ got going, EH controlled the zones, progressively closing the HR92s in a zone as the zone reached its target temperature. From running the CH 100% of the time when there was a cold zone, once all zones were near their target setpoint (and hence all HR92s were partially closed), EH started to ‘cycle’ the CH BDR91 at regular intervals and for short periods of time. Meanwhile, the WB boiler went through its own ‘shut down cycle’ whenever the CH BDR91 turned off and so was actually still running for a couple of minutes after EH thought it was turned off. In practice there could be only 1-2 minutes between the boiler shutting down and the next cycle starting. I was seeing the boiler ‘come alive’ at the start of each cycle, but the burners did not show as lit. Out flow temperature dropped to below 30C and hence the radiators were all but cold and as a result, zone temperatures started to fall from their setpoint. It was only when the zones dropped well below their setpoints, that EH ran the CH BDR91 for longer periods of time and at that point the burners fired.

    Those in the know, will recognise the EH behaviour as TPI (Time Proportional & Integral). The problem is that Honeywell confirmed that there is no way to control this behaviour – there are no ‘cycles per hour’ or ‘minimum run time’ parameters available outside of ‘boiler control’ – which was no longer in use. It seemed that there was intelligent software in the WB boiler which was not playing well with this constant short cycling!

    Maybe OpenTherm was the answer? EH has an OpenTherm bridge, but WB uses EMS. WB also has an OpenTherm bridge in their EasyControl range, but this is to allow their EasyControl range to talk to an OpenTherm boiler and not the other way around. WB technical support told me:

    “Worcester boilers do not support the Open-therm protocol as the Worcester controls operate using an EMS protocol. We would not be able to support an interface that converts from Open -therm to EMS as these would not have been tested with the products. Third party controls would only be supported if operating the boiler via a 230vac switched demand.”

    I contacted the Evohome shop (a great and friendly company who supplied my EH solution) and their support told me that IF every radiator had an HR92 fitted (a fully zoned solution), I should not have installed a motorised valve for the heating circuit, only for the HW, and then relied on the HR92s to prevent flow around the heating circuit. In this model, the CH BDR91 would have been installed as a boiler control – giving me access to the EH parameters I needed.

    Phase 3 – The Final Solutions
    I needed to find a way to make the WB less sensitive to ‘short burn cycles’ and to get access to the relevant parameters within EH – and hopefully without any plumbing changes! I therefore changed the EH configuration again:

    First, I cleared the EH/BDR91 config and reran the Guided Configuration as a Stored Hot Water only system – this paired only the CS92 and the HW BDR91. I then manually paired the CH BDR91 as a Boiler Controller.

    Rather than change the wiring, the CH BDR91 still operates the CH motorised valve and therefore triggers the boiler through the existing wiring from that valve. This means that when there is CH demand, the CH valve opens and the boiler fires. When there is HW demand, BOTH valves open.

    At first glance, this looks wrong, but in practice this is the same as if the CH valve had been removed and the CH BDR91 connected to the boiler directly! So long as all the HR92s are closed (Zone up to temperature/low setpoint/heating off), there will be no flow around the CH plumbing – hence the CH valve is effectively acting as the bridge to the boiler controller.

    Now that I have the CH BDR91 defined as Boiler Control, I have access to the EH ‘cycles per hour’ and ‘minimum run time’ parameters!

    The largest value for the EH ‘minimum run time’ is 5 minutes – which is now set. On the WB side, there is a parameter called ‘Standby Time’ which controls the ‘Anti Cycle Mode’ (option 3-b2 for the record). The default is 5 minutes – which explains why the burners never fired in the phase 2 scenario! By reducing this to 3 minutes (and with the EH minimum run time set to 5 minutes), the burners are now running on every cycle.

    So far, phase 3 is delivering the goods and remains the current configuration!

    In Closing
    For anyone who has an EH solution and a need to install a modern (non Opentherm) boiler, I hope there are some ideas in here which will help the ‘clever’ software on both sides play better together! Of course, there may be a much better solution..

    I am still open to a means to bridge EH to WB’s boiler control more intelligently (OpenTherm to EMS? EH to EasyControl bridge?), provided that this would not invalidate the multi-year manufacturer warranty offered by WB.

    Phase 3 seems to be a fine end point, but is anyone able to offer a suggestion for Phase 4?
    hi I've been running EH via BDR relay for 18 months and it's been reliable. Having recently installed a WB life 8000 combi I thought I should try out the opentherm bridge setting instead via nefit opentherm to EMS adaptor.
    I have just reverted back to BDR relay after a week as I was unable to control the boiler firing. It would run non stop even if there was no demand from the R8810 OT bridge. Removing the link between the 240out and LR CH connections stops it firing completely even with demand on. I dont know if WB and EH can work properly via OT yet to come across a working solution.

  4. #4
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    Hi

    I too have a Worcester boiler and Evohome.

    When installed it would, if over a degree below, get to the desired temperature but as it cooled it would not maintain it. The boiler simply came on for 1 minute every 10 minutes which meant no heat getting to radiators as Worcester seems to slow start.

    Even after 3 weeks the system had not learnt and simply kept pulsing the boiler on for 1 minute in every 10. The installers tried to fix it but to no avail "must be still learning".

    Luckily I found this post and used the settings for Evohome and boiler as in phase 3 of the OP and it now gets to the set temperature.

    If anyone else has a similar setup then I suggest that they use the settings (if only as an initial base) as I am now happy with the system.

    Thanks go to PRBUK

  5. #5
    Automated Home Guru
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    Interesting, I went on a similar journey through phase 1 and phase 2, but didn't need to go any further. My boiler is a Viessmann Vitodens 100 and fortunately seems quite happy short cycling on TPI, it fires every time, the burner comes on, then cuts out after 1 minute when on the shortest TPI cycle. The cycle gets progressively longer as heat demand rises, also it modulates as required, normally it runs on minimum flame height (if flow temperature is sufficient) unless an HR92 opens and dumps a load of cool water into the circuit, then the boiler detects this and will increase the flame height if required. Sometimes TPI will shut the boiler down in the middle of a burn at > minimum but it doesn't seem to cause any issues, I guess I was just lucky with my choice of boiler. I selected Viessmann for the steel hex as I have an open vent system fed via softened mains water. This is my first winter with EH and so far I've been really happy with the comfort levels. I'm now using domoticz to monitor the temperatures in each zone (just via EH API), what a great piece of software! :-)

  6. #6
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    Quote Originally Posted by PRBUK View Post
    Thank You for the posts on this site for helping me resolve some Evohome configuration questions. Once you know the answers, it seems so easy - but not before. I hope my story and experiences below will be helpful to future visitors.

    Phase 1, The Legacy System!
    My original installation had mechanical Thermostatic Radiator Valves (TRVs) on nearly all radiators and a single thermostat on the hall wall. When the thermostat called for heat, the Central Heating (CH) pump started and all rooms went to their set temperature, unless the hall heated first and the thermostat turned off the CH pump!

    Thanks to an article in PC Pro by a certain Paul Ockenden (thank you Paul!) , I converted the system to Evohome (EH). The TRVs were replaced with EH HR92 Radiator Controllers and an EH Wireless Relay Box (BDR91) was connected to the boiler in place of the wires from the hall thermostat. The BDR91 was paired to the ‘Boiler Control’ on the EH controller. Since the BDR91 was playing the role of CH thermostat, this configuration worked perfectly, and the EH 'Boiler Control' parameters were available to fine tune the configuration.

    Phase 2, A new Boiler.
    When the old boiler failed, I replaced it with a Worcester Bosch 8000 Life Regular Boiler and a Greenstore unvented Hot Water tank. The installation was performed to an S plan configuration, with one pump and two motorised valves. The ‘old’ BDR91 was to be re-tasked to the Central Heating and an EH Hot Water kit (ATF500DHW) was acquired, which contained a Wireless Cylinder Thermostat Transceiver (CS92) and a second BDR91.

    I think it is fair to say that the EH installation manual is a little light when it comes to understanding – and the wording in the Guided Configuration on the EH controller gives rise to further confusion! The Guided Configuration refers to ‘Stored Hot Water Configuration’, which implies that the other option must relate to heating – this is NOT the case! The Stored Hot Water configuration option will allow you to configure the Hot Water Sensor (CS92) and BOTH BDR91s controlling the motorised valves for Hot Water and Central Heating. The confusion continues when you look at ‘System Devices’ on the EH Controller and see that there is an option for Stored Hot Water and Boiler Control!

    As I had previously controlled the heating in phase 1 through the ‘boiler control’ (emulating the thermostat), it took research on this forum to understand the ‘new paradigm’. The motorised valves contain an electrical connection to the boiler that activates the boiler when the valve is open. Therefore, once either valve opens (due to CH or HW heat demand), the boiler will be fired. In this ‘S’ plan model there is no need for ‘boiler control’ – it is built in via the valves. So, to convert my system to S Plan, I had to 1) Set boiler control to NONE (ie remove the phase 1 use of boiler control) 2) Reset/Initialise the pairing on the BDR91s (press and hold the button until it fast blinks red) and then 3) Run the Stored Hot Water Configuration option, which paired the Hot Water Sensor, then the HW BDR91 and then the CH BDR91. A quick test and all was working.

    Beyond Phase 2 – When Worcester Bosch (WB) and EH do not play well together!
    It took a few weeks to work this out, but….

    As the ‘heating season’ got going, EH controlled the zones, progressively closing the HR92s in a zone as the zone reached its target temperature. From running the CH 100% of the time when there was a cold zone, once all zones were near their target setpoint (and hence all HR92s were partially closed), EH started to ‘cycle’ the CH BDR91 at regular intervals and for short periods of time. Meanwhile, the WB boiler went through its own ‘shut down cycle’ whenever the CH BDR91 turned off and so was actually still running for a couple of minutes after EH thought it was turned off. In practice there could be only 1-2 minutes between the boiler shutting down and the next cycle starting. I was seeing the boiler ‘come alive’ at the start of each cycle, but the burners did not show as lit. Out flow temperature dropped to below 30C and hence the radiators were all but cold and as a result, zone temperatures started to fall from their setpoint. It was only when the zones dropped well below their setpoints, that EH ran the CH BDR91 for longer periods of time and at that point the burners fired.

    Those in the know, will recognise the EH behaviour as TPI (Time Proportional & Integral). The problem is that Honeywell confirmed that there is no way to control this behaviour – there are no ‘cycles per hour’ or ‘minimum run time’ parameters available outside of ‘boiler control’ – which was no longer in use. It seemed that there was intelligent software in the WB boiler which was not playing well with this constant short cycling!

    Maybe OpenTherm was the answer? EH has an OpenTherm bridge, but WB uses EMS. WB also has an OpenTherm bridge in their EasyControl range, but this is to allow their EasyControl range to talk to an OpenTherm boiler and not the other way around. WB technical support told me:

    “Worcester boilers do not support the Open-therm protocol as the Worcester controls operate using an EMS protocol. We would not be able to support an interface that converts from Open -therm to EMS as these would not have been tested with the products. Third party controls would only be supported if operating the boiler via a 230vac switched demand.”

    I contacted the Evohome shop (a great and friendly company who supplied my EH solution) and their support told me that IF every radiator had an HR92 fitted (a fully zoned solution), I should not have installed a motorised valve for the heating circuit, only for the HW, and then relied on the HR92s to prevent flow around the heating circuit. In this model, the CH BDR91 would have been installed as a boiler control – giving me access to the EH parameters I needed.

    Phase 3 – The Final Solutions
    I needed to find a way to make the WB less sensitive to ‘short burn cycles’ and to get access to the relevant parameters within EH – and hopefully without any plumbing changes! I therefore changed the EH configuration again:

    First, I cleared the EH/BDR91 config and reran the Guided Configuration as a Stored Hot Water only system – this paired only the CS92 and the HW BDR91. I then manually paired the CH BDR91 as a Boiler Controller.

    Rather than change the wiring, the CH BDR91 still operates the CH motorised valve and therefore triggers the boiler through the existing wiring from that valve. This means that when there is CH demand, the CH valve opens and the boiler fires. When there is HW demand, BOTH valves open.

    At first glance, this looks wrong, but in practice this is the same as if the CH valve had been removed and the CH BDR91 connected to the boiler directly! So long as all the HR92s are closed (Zone up to temperature/low setpoint/heating off), there will be no flow around the CH plumbing – hence the CH valve is effectively acting as the bridge to the boiler controller.

    Now that I have the CH BDR91 defined as Boiler Control, I have access to the EH ‘cycles per hour’ and ‘minimum run time’ parameters!

    The largest value for the EH ‘minimum run time’ is 5 minutes – which is now set. On the WB side, there is a parameter called ‘Standby Time’ which controls the ‘Anti Cycle Mode’ (option 3-b2 for the record). The default is 5 minutes – which explains why the burners never fired in the phase 2 scenario! By reducing this to 3 minutes (and with the EH minimum run time set to 5 minutes), the burners are now running on every cycle.

    So far, phase 3 is delivering the goods and remains the current configuration!

    In Closing
    For anyone who has an EH solution and a need to install a modern (non Opentherm) boiler, I hope there are some ideas in here which will help the ‘clever’ software on both sides play better together! Of course, there may be a much better solution..

    I am still open to a means to bridge EH to WB’s boiler control more intelligently (OpenTherm to EMS? EH to EasyControl bridge?), provided that this would not invalidate the multi-year manufacturer warranty offered by WB.

    Phase 3 seems to be a fine end point, but is anyone able to offer a suggestion for Phase 4?
    I know it's been a few years since you wrote this but I wondered how you were getting on with it? We currently have a WB Greenstar 35 System with all rads using HR92 and I am trying to check the system is running efficiently.

    I have tried to get a connected specialist out but they are just not interested and the initial installer has gone awol.

    Thanks
    Mark

  7. #7
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    Quote Originally Posted by mark8par View Post
    I know it's been a few years since you wrote this but I wondered how you were getting on with it? We currently have a WB Greenstar 35 System with all rads using HR92 and I am trying to check the system is running efficiently.

    I have tried to get a connected specialist out but they are just not interested and the initial installer has gone awol.

    Thanks
    Mark
    The system has worked perfectly since I installed it. All zones adjust and maintain their desired heat schedule and the water is always hot! The best advice is to let it do its thing if the zone schedules are working as expected - don't try to out think what the boiler should be doing! Unless the system is not performing as expected, there is probably little benefit in having a system review (regular boiler servicing is different and strongly advised of course)

    The only adjustment I made after the initial install was to lower to Evohome 'Cycle Rate' to 3 per hour (with a 'Minimum On Time'=5 ) this worked far better than the higher cycle rate I started with.

    I also noticed that my evohome controller did not have the latest firmware (the main screen did not show the 'smart features' button referenced in other posts). I sent an email to [email protected] with my controller's MAC address and CRC number and they pushed the new firmware to them.

    Folllowing an earlier dicussion on PM with CW101, I shared the full set of changes I made to my boiler's config - you can find them here https://1drv.ms/u/s!AlOvuCMfBp3hhMMw...G5kRQ?e=9gWWwi . On the evoHome side, 'Cycle Rate'=3 per hour, 'Minimum On Time'=5 min, 'Boiler Control'=Wireless Relay Box

    Hope this helps

  8. #8
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    Quote Originally Posted by PRBUK View Post
    The system has worked perfectly since I installed it. All zones adjust and maintain their desired heat schedule and the water is always hot! The best advice is to let it do its thing if the zone schedules are working as expected - don't try to out think what the boiler should be doing! Unless the system is not performing as expected, there is probably little benefit in having a system review (regular boiler servicing is different and strongly advised of course)

    The only adjustment I made after the initial install was to lower to Evohome 'Cycle Rate' to 3 per hour (with a 'Minimum On Time'=5 ) this worked far better than the higher cycle rate I started with.

    I also noticed that my evohome controller did not have the latest firmware (the main screen did not show the 'smart features' button referenced in other posts). I sent an email to [email protected] with my controller's MAC address and CRC number and they pushed the new firmware to them.

    Folllowing an earlier dicussion on PM with CW101, I shared the full set of changes I made to my boiler's config - you can find them here https://1drv.ms/u/s!AlOvuCMfBp3hhMMw...G5kRQ?e=9gWWwi . On the evoHome side, 'Cycle Rate'=3 per hour, 'Minimum On Time'=5 min, 'Boiler Control'=Wireless Relay Box

    Hope this helps
    Thanks for the reply, do you think this setup might work for me? The reason I was is that we have a dump radiator in the hallway with no TRV (HR92) so this might result in when hot water is called for it would always heat this.

    Cheers

  9. #9
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    Quote Originally Posted by mark8par View Post
    Thanks for the reply, do you think this setup might work for me? The reason I was is that we have a dump radiator in the hallway with no TRV (HR92) so this might result in when hot water is called for it would always heat this.

    Cheers
    That depends on the design at the boiler. My system has a pump connected to two motorised valves (Y design). One controls flow to the CH and the other to the HW. Each valve is controlled by the evohome by a BDR91 relay. So if none of the radiators are calling for heat, the CH valve remains closed and there is no flow to any radiator. Between the pump and the valves there is a return loop containing a pressure relief valve, so if the pump runs and both valves are closed, there is a route from flow to return.

    I originally had the same design, with a 'dump' radiator in the hall. When the boiler was replaced with the Bosch, I had the radiator valve replaced so I could fit an HR92 - now all radiators are controlled. The return loop does the job that the 'dump' radiator did in the previous design.

    In practice, when the BDR91 controlled valves close, the boiler has a run down time when the pump continues to run (to avoid hot spots in the boiler), so the return loop is used on a regular basis.

  10. #10
    Automated Home Guru
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    Jan 2018
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    Quote Originally Posted by DanD View Post
    A partial solution to Phase 4 which you may already be aware of is the 'Nefit EMS-OT OpenTherm converter' described on this page:

    https://myboiler.com/opentherm/worce...sch-opentherm/

    It's only a partial solution as I can't comment on any potential impact on the WB warranty. I think another user has tried this with their WB boiler, but wasn't impressed with the outcome and reverted back to the original controls

    https://www.automatedhome.co.uk/vbul...-maybe-Evohome

    I've done something similar with my Glow Worm boiler and added an Opentherm interface as the boiler only supported either Glow Worm's 'smart' controls or a standard on/off RT connection. I ran my Evohome system for a couple of years via the RT connection and it worked really well. However, adding the Opentherm interface earlier this year now allows control of the boiler via the Honeywell R8810 Opentherm bridge and I'm pleased with the outcome and temperature control is improved within each zone (confirmed by extensive obsessive monitoring ) and I've not had any concerns about the boiler firing/gas usage.
    FWIW: I use a Nefit EMS-OT (obtained from ROBBshop) on a WB Greenstar 26si (with a Honeywell/Resideo R8820A OTG) in the UK and it works *very* well for me.

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