Help with Combi boiler and zone airing cupboard

[shaun2345]

Hi all

I have just moved into a house and the airing cupboard does not air, I have a spare small rad and the Combi is only above the cupboard so what I was thinking ..

At the mo the baxi boiler has a feed and return for the heating .

If I made the airing cupboard the 1st rad in the heating loop, then after the feed to the airing cupboard fit a two way valve ..

I have the main heating setup on a hive so I then put the main heating hive into and out of the new two way valve so that when I call for main house heating the new two way valve opens , thus also powering the pump in the boiler so the heating fires up and heats the new airing cupboard and the house …

I have a spare hive thermostat which I fit to the boiler and fit this into the airing cupboard set it high so when the cupboard cools down the boiler cuts in and heats only the airing cupboard not the house as the new two way valve will be shut ?

Does this make sense and does any one know if it’s possible if not I’m going to
Have to fit two 2 way valves and a pressure relief valve ..

Thanks I’m advance for any help

Shane

 

[Deleted member 267285]

Doesn’t make sense to me, if you’re bringing this additional rad on with the house, why would you need a 2 port motorised zone valve?

 

[shaun2345]

So I can run it on a thermostat in the summer for airing cupboard when rest of system is shut off

 

[Deleted member 267285]

Yes just crate an additional zone then.

 

[shaun2345]

Add one two way valve after the airing cupboard rad then wire the thermostat to that valve ? Do you think this will be ok

 

[Harry Bloomfield]

Wouldn't a low power electric heater on a stat, be more sensible and economic?

 

[oldbutnotdead]

Yes your plan will work in theory. Depending on how big or (more accurately what power your spare rad can emit) and if/how well the boiler can modulate down, the boiler may cycle frequently when only the airing cupboard is being heated.
You also need to check any requirements for your boiler/system needing a bypass valve (to allow circulation after heat demand has ceased to cool the heat exchanger).
You'd want to think about a TRV on that rad as well, without it the airing cupboard will get very warm (since it'll be heating constantly when the house is heating) but you'd need to set the setpoint carefully so it and the local Hive don't start squabbling (if local Hive is at 22 Deg the TRv would need to be set to at least 25 Deg).

 

[shaun2345]

Yes your plan will work in theory. Depending on how big or (more accurately what power your spare rad can emit) and if/how well the boiler can modulate down, the boiler may cycle frequently when only the airing cupboard is being heated.
You also need to check any requirements for your boiler/system needing a bypass valve (to allow circulation after heat demand has ceased to cool the heat exchanger).
You'd want to think about a TRV on that rad as well, without it the airing cupboard will get very warm (since it'll be heating constantly when the house is heating) but you'd need to set the setpoint carefully so it and the local Hive don't start squabbling (if local Hive is at 22 Deg the TRv would need to be set to at least 25 Deg).

Thank you yes that’s a good thought or I just twin zone on two valves with the thermostat because then it can run seperate I have the room for two valves but just trying to simplified the setup . I thought by using the boiler setup on the new rad in airing cuboard it would hopefully take away excess heat anyone got a good example wiring diagram of what o would please ? My boiler is a baxi duo tec 28

 

[oldbutnotdead]

Depending on how many rooms you have you might want to look at wireless trvs- yes they're about £40 per rad at the moment (plus hub) but they can give you very fine control over what you heat when.
EDIT Modern setups don't permit a radiator to be used as a bypass (think that's for energy efficiency rather than technical reasons)- if you did use it as a bypass then it would be heating whenever the boiler was running (you'd need the lockshield trimmed down a lot!)