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Thread: Electronic TRV's 2012

  1. #11
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    Quote Originally Posted by chris_gla View Post
    thanks for the info Chris... the idea for having all TRV with no room stat or bypass with a Grundfos Alpha came from another forum...

    I think the view was right to a degree as on the system I have the room stat doesn't control the boiler directly, but does via a Boilermate thermal store. This may stop the cycling to a degree, that said it doesn't get away from the part L need for boiler interlock and that although the Alpha will modulate it's just not a good idea running it into a "closed circuit"!

    I think I've came down to one of three systems- none have a "room stat" but all have a boiler interlock which any of the digital wireless TRV's can control:-
    1) Honeywell Evo, CM zone or similar using HR80 wireless TRV's. Very good, circa 50 per room but web control seems expensive
    2) Lightwave RF. Similar to the Honeywell system but a bit more open standards due to other Lughtwave RF kit/ controllers being available.
    3) Danfoss Living Connect. Contacted Danfoss about this as a few places have them but they aren't officially released in the UK until later in 2012. Again, wireless TRV's but this time they use Zwave meaning you could use a Zwave PIR for instance to detect a room being occupied and switching on/ increasing temp in any room.

    All three have boiler interlock which replaces room stat to turn any traditional TRV system into multizone only by changing the TRV head- not the complete valve. They all have some degree of fuzzy logic to reduce cycling, exercise closed valves weekly, etc.

    Pegler have quite a few references on their site which show potential savings and I can see how these would work for my lifestyle (close bed TRV's most of the day, only open office TRV when I'm actually in the house and it's a work day, allow remote control of other TRV's for when I know there is no one at home). Pegler are cheaper but are just TRV heads with no interlock/ remote option so not so good for my use.

    As it stands I'll probably wait until the Danfoss Living Connect become available and then buy a few of them plus either a Danfoss or Horstmann Zwave boiler interlock to get started and as a "basic" reliable system, then add a Vera controller for remote options and more clever stuff over the top.

    All in it looks like around 1500 for everything but it isn't unreleastic to think that I could save 200 - 300 a year (15 - 25%) by automating some tasks.

    The new pump and hall TRV's are the only bits I'd need to drain system down for- I'm likely to get a heating engineer for this to desludge, etc as the system is now 10 years old.


    Hello Chris,

    Thanks for your reply - You are obviously much more enlightened than I first thought regarding your knowledge of Heating Systems / Your own Heating System - I obviously did not know this when I Posted My message about the Room Thermostat - Automatic Bypass etc.

    It seems to Me that you have made your well researched selection on which Radiator Digital / RF / TRV`s to use to independantly control the Radiators in your Home - I cannot recommend or otherwise the Danfoss Products that You may have decided on as I have not installed any of them - but Danfoss produce quality products for the Heating Industry and are definitely a well known / well respected / reputable Company.

    I install mainly Honeywell Heating Controls and I personally feel that they cannot be bettered by any Heating Controls Manufacturer - But You mentioned that The Honeywell Evohome Controls are perhaps offering facilities that you don`t need / want - and at a Cost that can be `beaten` by using the Danfoss System Controls.


    I hope that You were not offended by what I wrote in My first reply to your Post - I had thought that I was helping a person who did NOT realise the importance of a Room Thermostat / Boiler Interlock and System Bypass etc. - but after receiving your reply I can see that You are NOT a `Novice` in understanding the `Workings` of a Heating System.


    Good Luck in whatever You finally decide upon - I hope that you configure a Fully Controllable - Energy Efficient Heating System for your Home.


    Chris
    Last edited by CHRISMU; 3rd July 2012 at 01:18 AM.

  2. #12
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    I have installed a number of these: FHT80BTF from Conrad-UK.

    While they do shut down all the radiators, control of the boiler is achieved through something called an FHT8W boiler interlock. I have installed this in place of my old danfoss 103 timer. When all radiators are closed, the interlock shuts down the boiler. When any one radiator opens more than a set percentage (I have chosed 10%) the interlock comes on and the boiler runs.

    I do have a bypass radiator - it's in the bathroom but technically I don't believe it is necessary as the boiler pump won't be running unless heat is being demanded elsewhere in the house. Being a towel rad, fitting a TRV to it would be difficult and look odd anyway.

    My house has never had a room stat anywhere, the conrad system replaced a timer and all TRV'd radiators (no bypass and no interlock). I'm no heating engineer, but it seems to me that having a room stat in the coldest room (usually one you don't actually spend any time in anyway), running the boiler constantly until that room gets warm and artificially throttling back the heat output in other rooms using traditional wax filled TRV's is an approach that is way beyond it's best before life.

    Just my two penneth worth.
    Chris

    Automating my home in a family friendly way - My blog: http://www.cpmills.com/

  3. #13
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    Quote Originally Posted by fredd500 View Post
    I have installed a number of these: FHT80BTF from Conrad-UK.

    While they do shut down all the radiators, control of the boiler is achieved through something called an FHT8W boiler interlock. I have installed this in place of my old danfoss 103 timer. When all radiators are closed, the interlock shuts down the boiler. When any one radiator opens more than a set percentage (I have chosed 10%) the interlock comes on and the boiler runs.

    I do have a bypass radiator - it's in the bathroom but technically I don't believe it is necessary as the boiler pump won't be running unless heat is being demanded elsewhere in the house. Being a towel rad, fitting a TRV to it would be difficult and look odd anyway.

    My house has never had a room stat anywhere, the conrad system replaced a timer and all TRV'd radiators (no bypass and no interlock). I'm no heating engineer, but it seems to me that having a room stat in the coldest room (usually one you don't actually spend any time in anyway), running the boiler constantly until that room gets warm and artificially throttling back the heat output in other rooms using traditional wax filled TRV's is an approach that is way beyond it's best before life.

    Just my two penneth worth.

    "Hello fredd500",

    I was interested to read that You installed Radiator Valve Controls and a Boiler Interlock Control to your Heating System.


    Some of my `emphasised` comments are directed at other readers - not You.


    I agree with most of your comments - But a couple of my comments about a Heating System Controls etc. would be:


    Having a Boiler Bypass is not only a requirement of Part L of the Building Regulations but most New / High Efficiency Boilers require that Heat is dissipated from the Heat Exchanger when the Thermostatic Control or Time Control shuts off the Boiler during a period when it is `Firing` - in case that the system circulation is stopped at the same time as the Boiler is stopped from Firing.

    This Bypass should be of a `Minimum Length` - as stipulated by the Boiler Manufacturer But - NOT a very long run of Flow and Return Pipework to for example a `Bypass Radiator` - and must have an `Automatic Bypass Valve` which opens by an increase in pressure IF circulation has been stopped either by Zone Valves closing or all TRV`s being closed / `satisfied` [usually unlikely but not impossible] - NOT a Gate Valve / Lockshield Valve or Radiator Valves.


    Installing the type of Controls that You have decided upon and installed - WITH the addition of a Boiler Bypass which includes an Automatic Bypass Valve is definitely much better than just ordinary TRV`s and a Room Thermostat - BUT Most people either could not afford these - or would simply not agree to Pay for them if offered as an option for controlling their Heating System - a New System or Existing System `Controls Upgrade`.

    That is why for Domestic Heating Systems Heating Engineers still recommend / adhere to the `usual method` of satisfying both the Buliding Regulations in `Part L` and installing affordable / easy to use Heating Controls such as Programmers / Timeclocks / Programmable Room Thermostats [and conventional room thermostats] - Radiator TRV`s - Zone Valves and a Boiler Bypass with Automatic Bypass Valve etc.

    Regarding your comment about having a Room Thermostat in the coldest part of the House and then `artificially throttling back the heat output in other rooms` - this is not really what would be done in practical terms if people find themselves in that position.


    Although this next comment is NOT at all in adherence with a `Calculated / Technical Approach` it is a practical approach:


    The occupant of the Home would be advised or find out for themselves that they should Set the Room Thermostat to a lower Temperature than that usually required / imagined - the rest of the Home would still have reached a desireable / comfortable temperature when the Room Thermostat was satisfied - this could easily be determined by trial and error.

    Although I realise that this is NOT the `Scientific approach` - there are very few Homes where the Room temperatures can be exactly regulated - there will always be some trial and error adjustments regarding temperatures.

    If the Room Thermostat - which in a `normal domestic heating system` is a requirement of Part L of the Building Regulations is NOT fitted in the `Coldest Area` of the Home then that Room / Area would NOT reach the desired temperature when the Room Thermostat was satisfied - meaning that this Room / Area would possibly remain too `Cool` - depending on whether there was Heat Gain from the surrounding Rooms / Areas.

    When people have a Heating System that does not have a Room Thermostat or an Efficient form of Boiler Interlock that operates on a Temperature Setting[s] the Boiler will be Firing to satisfy the Boiler Thermostat setting - `Cycling` - this is a VERY serious waste of Gas !

    If a Heating System is operated in this manner no amount of Radiator TRV`s could make it an `Energy Efficient` / `Cost Effective use of Gas` System.


    As I mentioned above some of these comments are directed at other readers - especially as You have decided that the previous comments of `Us Heating Engineers` are `Not Up to date` [`an approach that is way beyond it's best before life`].


    Regards,


    Chris - Heating Engineer / Contractor and Registered Gas Engineer
    Last edited by CHRISMU; 6th October 2012 at 12:22 AM.

  4. #14
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    Chris

    Thanks for your reply. This is indeed interesting and although I have to admit that most of it goes over my head, it does make me wonder how poor my installation must be.

    The background is that I bought a house with an ancient Valliant boiler in it. All rooms had TRVs (and worryingly of about three or four different makes) and a simple Danfoss 103 timer. No central room stat. There was no bypass radiator (later recommended to me by someone else) so the worst case was the timer was on and all rads satisfied so unless there was some sort of internal bypass in the boiler there would have been nowhere for the hot water to go.

    When that boiler was eventually condemed (by an over zealous BG engineer looking for a quick commission on a new one - don't get me started on that!) I had it replaced with what is possibly turning out to be a bit of a turkey (Baxi 105HE) but it was a straight forward swap out - I don't believe the engineer even power flushed the system. We even left the old 103 timer in place. It was only later that I added a rad in the bathroom and left that open all the time (which reminds me - it was leaking a bit so I closed it - must fix this and re-open tonight!).

    I do notice that the boiler has some overrun - there is a period of time after the interlock shuts off, that the boiler keeps pumping for before shutting down completely - one assumes this is to remove any residual heat from the heat exchanger? I installed the interlock myself (I think the control system I have goes over the heads of my usual plumbers) and I did this by just working out what the 103 timer was doing (opening/closing a relay in response to the timed programme) and then wiring the interlock in the same manner. It works and has worked for some time. One assumes the relay is simply wired to some internal terminals that would ordinarilly be connected to the thermostat?

    Chris (fredd500 - way too many Chris' on this post!!!)
    Chris

    Automating my home in a family friendly way - My blog: http://www.cpmills.com/

  5. #15
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    Quote Originally Posted by fredd500 View Post
    Chris

    Thanks for your reply. This is indeed interesting and although I have to admit that most of it goes over my head, it does make me wonder how poor my installation must be.

    The background is that I bought a house with an ancient Valliant boiler in it. All rooms had TRVs (and worryingly of about three or four different makes) and a simple Danfoss 103 timer. No central room stat. There was no bypass radiator (later recommended to me by someone else) so the worst case was the timer was on and all rads satisfied so unless there was some sort of internal bypass in the boiler there would have been nowhere for the hot water to go.

    When that boiler was eventually condemed (by an over zealous BG engineer looking for a quick commission on a new one - don't get me started on that!) I had it replaced with what is possibly turning out to be a bit of a turkey (Baxi 105HE) but it was a straight forward swap out - I don't believe the engineer even power flushed the system. We even left the old 103 timer in place. It was only later that I added a rad in the bathroom and left that open all the time (which reminds me - it was leaking a bit so I closed it - must fix this and re-open tonight!).

    I do notice that the boiler has some overrun - there is a period of time after the interlock shuts off, that the boiler keeps pumping for before shutting down completely - one assumes this is to remove any residual heat from the heat exchanger? I installed the interlock myself (I think the control system I have goes over the heads of my usual plumbers) and I did this by just working out what the 103 timer was doing (opening/closing a relay in response to the timed programme) and then wiring the interlock in the same manner. It works and has worked for some time. One assumes the relay is simply wired to some internal terminals that would ordinarilly be connected to the thermostat?

    Chris (fredd500 - way too many Chris' on this post!!!)

    "Hello again Chris",


    Thanks for your reply.


    As You have a Baxi 105 HE Combination Boiler I can give you some `reassurance` regarding a couple of points:


    This Combi Boiler has an integral `Automatic Bypass` which will allow the Pump Over-run to not be pumping against no circulation in the unlikely event that this were to occur.

    Depending upon the circumstances regarding the Boiler Interlock this `Built In` Bypass would not really be capable of Heat Dissipation because there is simply not enough pipework to dissipate the Heat - but this should not cause any problems as usually there is always some circulation around the Heating System - unless all the TRV`s were closed at the same time - which could in theory happen.

    Without checking I think that I remember the Baxi 105 HE has up to a 30 Minute Pump Over-run [?] - an unusually long period of time - and obviously this would mean that the Flow and Returns would have circulation for that period of time.


    Obviously You already know that there is a Hot Water `Pre Heat` Facility on the Combi which will [if selected] cause the Boiler to Fire Up to Heat the small Hot Water store within the Combi - this would happen frequently - so that will also cause the Pump Over-run to operate frequently although in this case only for approximately 30 Seconds.

    I assume that You have a Copy of the User and Installation Instructions for the Baxi 105 HE - ? - some of the brief descriptions of operation might be useful to read to see the process / sequence of operation.


    I cannot comment upon the Wiring for the Boiler Interlock - for two reasons:


    Without seeing the exact wiring diagrams it would not be possible.

    And also - since approximately 2005 it has been a requirement under `Part P` of the Building Regulations for Electrical Works to be carried out by a `Competent Person` - this means in law an Electrician who has the necessary Qualifications and is Registered with an Electrical Competent Persons Scheme - for example NICEIC - it would definitely be inappropriate for Me to advise on Electrical Wiring on this Forum or any other.


    Up to 2005 I had previously been deemed as `Competent` in Essential Electrics and Electrical Installation for Mechanical Services having taken Training and Assessment in those - `ACOPS` - `Approved Code of Practice` Training and Assessment - recognised as `Additional Qualifications` within the Heating and Gas Industries - although hated by Professional Electricians for obvious reasons.

    I then completed `Training and Assessment` for `Defined Scope` [Heating and Gas Appliances] Part P and I Registered with an Electrical Competent Persons Scheme - this process was `Valid for 5 Years` [Re-register every Year] but as the costs are `prohibitive` for someone who is NOT trading as an Electrician I let this lapse in 2010.

    These `Defined Scope` Part P Training and Assessment Courses are also hated by most Professional Electricians for the same reason.


    Because of the Building Regulations in `Part P` and obviously the possible Dangers of carrying out Electrical Works / Testing etc. I feel that I am not able to give any Advice or Information about the Electrical Wiring of Heating Controls etc. on a Forum.

    My Heating Systems are all wired up by a Fully Qualified and Registered Electrician - any Electrical Faults on New Boilers are obviously covered and dealt with by a Service Engineer from the Boiler Manufacturer under the Warranty - although I would be able to diagnose what component was at fault by various tests.


    I hope that these comments are of some help Chris.


    Regards,

    Chris
    Last edited by CHRISMU; 6th October 2012 at 12:31 AM.

  6. #16
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    Default Edit for my post above

    Quote Originally Posted by CHRISMU View Post
    "Hello again Chris",


    Thanks for your reply.


    As You have a Baxi 105 HE Combination Boiler I can give you some `reassurance` regarding a couple of points:


    This Combi Boiler has an integral `Automatic Bypass` which will allow the Pump Over-run to not be pumping against no circulation in the unlikely event that this were to occur.

    Depending upon the circumstances regarding the Boiler Interlock this `Built In` Bypass would not really be capable of Heat Dissipation because there is simply not enough pipework to dissipate the Heat - but this should not cause any problems as usually there is always some circulation around the Heating System - unless all the TRV`s were closed at the same time - which could in theory happen.

    Without checking I think that I remember the Baxi 105 HE has up to a 30 Minute Pump Over-run [?] and obviously this would mean that the Flow and Returns would have circulation for that period of time.


    Obviously You already know that there is a Hot Water `Pre Heat` Facility on the Combi which will [if selected] cause the Boiler to Fire Up to Heat the small Hot Water store within the Combi - this would happen frequently - so that will also cause the Pump Over-run to operate frequently

    I assume that You have a Copy of the User and Installation Instructions for the Baxi 105 HE - ? - some of the brief descriptions of operation might be useful to read to see the process / sequence of operation.


    I cannot comment upon the Wiring for the Boiler Interlock - for two reasons:


    Without seeing the exact wiring diagrams it would not be possible.

    And also - since approximately 2005 it has been a requirement under `Part P` of the Building Regulations for Electrical Works to be carried out by a `Competent Person` - this means in law an Electrician who has the necessary Qualifications and is Registered with an Electrical Competent Persons Scheme - for example NICEIC - it would definitely be inappropriate for Me to advise on Electrical Wiring on this Forum or any other.


    Up to 2005 I had previously been deemed as `Competent` in Essential Electrics and Electrical Installation for Mechanical Services having taken Training and Assessment in those - ACOPS.

    I then completed `Training and Assessment` for `Defined Scope` [Heating and Gas Appliances] Part P and I Registered with an Electrical Competent Persons Scheme - this process was `Valid for 5 Years` [Re-register every Year] but as the costs are `prohibitive` for someone who is NOT trading as an Electrician I let this lapse in 2010.


    Because of the Building Regulations in `Part P` and obviously the possible Dangers of carrying out Electrical Works / Testing etc. I feel that I am not able to give any Advice or Information about the Electrical Wiring of Heating Controls etc. on a Forum.

    My Heating Systems are all wired up by a Fully Qualified and Registered Electrician - any Electrical Faults on New Boilers are obviously covered and dealt with by a Service Engineer from the Boiler Manufacturer - although I would be able to diagnose what component was at fault by various tests.


    I hope that these comments are of some help Chris.


    Regards,

    Chris


    "Hello again Chris".


    Further to my message to You above - I need to submit an Edit to clarify something that I wrote:



    EDIT FOR THIS PARAGRAPH ABOVE:


    QUOTE:


    Depending upon the circumstances regarding the Boiler Interlock this `Built In` Bypass would not really be capable of Heat Dissipation because there is simply not enough pipework to dissipate the Heat - but this should not cause any problems as usually there is always some circulation around the Heating System - unless all the TRV`s were closed at the same time - which could in theory happen.


    END QUOTE


    I should have written that with MOST Heating Systems connected to a Combination Boiler there would usually always be some circulation path in operation.

    This situation can be different when there are Zones engineered into the system which use Electronic Zone Valves - depending upon how these zones are created and where the zone valves are installed there could be a situation where ALL circulation paths are closed - except for the Internal Automatic Bypass in the Combi Boiler.

    Obviously this does not apply to your system Chris - but I have written this Edit because of other readers - including other Heating Engineers who sometimes take pleasure in contradicting `Fellow Professionals`.

    That is NOT directed at the `Fellow Professional` who posted some useful information on this thread - neilhooper - My comment is prompted by experiences on other Forums.


    Regards,


    Chris
    Last edited by CHRISMU; 8th October 2012 at 06:48 PM.

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