Hi,
Last year we had an extension built which included 3 UFH zones. The existing part of the house is traditional rads.
The setup is:
BDR91 boiler control (Worcester combi)
HR92s on rads
HCC80r controlling actuators on the manifold for the UFH zones
Evohome is set up with each radiator and UFH zone as their own zone, which we can control individually. This is great, and what we were aiming for.
After the winter and getting used to the setup, we found we generally don't have the radiators on much, and the UFH zones tick over, keeping themselves at whatever temp we've set.
What is wrong with our setup is that all the heating is on a single pipe circuit. This means that each time the UFH calls for a bit of heat, the radiator pipes in the house fill up with very hot water, which is unused because none of the radiators are on. Firstly this is annoying because they creak like anything as they expand and contract in the middle of the night. Secondly this is inefficient as we only want to heat the UFH.
I realise what was missed out during our install was a zone value to separate the rads from the UFH. Ideally what we want is for some logic/control in the Evohome system to say "if any of the radiator zones are on then open a zone value, otherwise have it closed".
However, I've contacted Honeywell to ask how we could achieve this and they've basically said we can't! If we attached a second BDR91 to the system to control a zone valve then we would lose control of the individual radiators. Which we don't want.
I have two horrible ideas, but any further thoughts would be most welcome.
1. Put a manual zone valve in the rad circuit. During most of the year we would leave this closed so CH water only flows round the UFH pipes, being more efficient. During the depth of winter we open the manual value to bring the radiators into play. This option is rubbish - we would have to remember to turn the manual valve on and off, and would have no ability to turn any radiators on remotely/scheduled if the manual value wasn't open. It would also mean that when the valve is open, if only the UFH wants heat then hot water would still circulate round the radiator cicruit, wasting energy and making the pipes creak.
2. Setup a new 'Radiators' zone on Evohome which would be an Electric Heating zone (so that it doesn't fire up the boiler) with a second BDR91 to open and close a motorised zone value on the radiator circuit. I think we'd also need another thermostat. Most of the time this new zone would be set to some very low temperature, meaning the zone value was closed. If we then want the radiators to run we would edit the schedule or override for that radiator in Evohome, AND set the new 'Radiators' zone to some high temperature, causing Evohome to open the zone value and allowing CH water to flow to the rads. This is pretty horrible, but it's the best I can come up with for now.
Can anyone suggest a better approach please?
Last year we had an extension built which included 3 UFH zones. The existing part of the house is traditional rads.
The setup is:
BDR91 boiler control (Worcester combi)
HR92s on rads
HCC80r controlling actuators on the manifold for the UFH zones
Evohome is set up with each radiator and UFH zone as their own zone, which we can control individually. This is great, and what we were aiming for.
After the winter and getting used to the setup, we found we generally don't have the radiators on much, and the UFH zones tick over, keeping themselves at whatever temp we've set.
What is wrong with our setup is that all the heating is on a single pipe circuit. This means that each time the UFH calls for a bit of heat, the radiator pipes in the house fill up with very hot water, which is unused because none of the radiators are on. Firstly this is annoying because they creak like anything as they expand and contract in the middle of the night. Secondly this is inefficient as we only want to heat the UFH.
I realise what was missed out during our install was a zone value to separate the rads from the UFH. Ideally what we want is for some logic/control in the Evohome system to say "if any of the radiator zones are on then open a zone value, otherwise have it closed".
However, I've contacted Honeywell to ask how we could achieve this and they've basically said we can't! If we attached a second BDR91 to the system to control a zone valve then we would lose control of the individual radiators. Which we don't want.
I have two horrible ideas, but any further thoughts would be most welcome.
1. Put a manual zone valve in the rad circuit. During most of the year we would leave this closed so CH water only flows round the UFH pipes, being more efficient. During the depth of winter we open the manual value to bring the radiators into play. This option is rubbish - we would have to remember to turn the manual valve on and off, and would have no ability to turn any radiators on remotely/scheduled if the manual value wasn't open. It would also mean that when the valve is open, if only the UFH wants heat then hot water would still circulate round the radiator cicruit, wasting energy and making the pipes creak.
2. Setup a new 'Radiators' zone on Evohome which would be an Electric Heating zone (so that it doesn't fire up the boiler) with a second BDR91 to open and close a motorised zone value on the radiator circuit. I think we'd also need another thermostat. Most of the time this new zone would be set to some very low temperature, meaning the zone value was closed. If we then want the radiators to run we would edit the schedule or override for that radiator in Evohome, AND set the new 'Radiators' zone to some high temperature, causing Evohome to open the zone value and allowing CH water to flow to the rads. This is pretty horrible, but it's the best I can come up with for now.
Can anyone suggest a better approach please?
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