Thermostat for wet underfloor heating

[furtive]

I've already got a Honeywell CM907 room stat to control all the radiators in my house, but I'm having wet underfloor heating fitted to the kitchen. Am I right in thinking that I just need to get a simple room stat to control that or should I get another CM907?

[mk1fan]

Does the installation not include for connection to the existing system - for both water and controls?

Did you not ask the installer/designer about controls?

I'm not being rude. Just seems to be an odd question that the installer can answer.

Edited by mk1fan on Wednesday 9th February 10:56

[furtive]

mk1fan said:

Does the installation not include for connection to the existing system - for both water and controls?

Did you not ask the installer/designer about controls?

I'm not being rude. Just seems to be an odd question that the installer can answer.

Edited by mk1fan on Wednesday 9th February 10:56

I'm the designer! The system has options for thermostats - both standard and programmable. I just wondered which I should use considering I already have a progammable room stat for the radiators which will be the master control. Do I just need a standard digital stat for the underfloor heating?

[mk1fan]

I'd punt the question to your installer. Small, domestic job I'd get the fitter to design and install based upon how you want it to perform.

Yes, could have another programable stat, or a regular room stat or none at all. I don't think any are a 'must'.

Do all you rooms have a stat linked to your programable one or do you just have one controling the whole house?

If you're sending out information to get quotes I'd keep it a simple performance spec stating what you want the system to do and the floor area plus perimeter messurements. Also ask for a breakdown of the components required and priced for.

[FlossyThePig]

Doesn't underfloor heating run at a much lower temperature than external radiators? Your kitchen floor may get awfully hot.

[Paul Drawmer]

FlossyThePig said:

Doesn't underfloor heating run at a much lower temperature than external radiators? Your kitchen floor may get awfully hot.

Blending valve should do this.

[mk1fan]

Yes it does run at a lower temperature.

However, an UFH circuit can be added to a radiator circuit quite easily and not be 'hot'.

[furtive]

I have one programmable stat in the hallway that controls the whole house.

I'll need another stat in the kitchen to control when the underfloor heating turns on and off so that it doesn't get too hot or cold compared to the rest of the house.

I'm not sending out for quotes. The UFH system is being fitted tomorrow. I just wanted advice on which stat would be most suitable. I think a 7-day programmable one is overkill as I've already got one controlling the rest of the house, so am thinking a standard digital one would do the trick

But you are making me think it's not a simple as that...

[mk1fan]

I think a regular room stat will suffice. It's only going to control the manifold. opening ang closing.

Unless they are plumbing in a whole new dedicated circuit off the boiler and you need to control the boiler coming on and off too.

Speak to the fitters and tell them what you want the UFH to do / behave / be controlled to ensure what they've priced for and what they've ordered matches your requirements.

Never be affraid to talk to your builder / tradesman. You're paying them for their advice and expertise. A competent person will happily explain things to you - well to a point. If its the 100th time of asking the same thing I expect a few will get 'funny'.

Edited by mk1fan on Wednesday 9th February 14:34

[furtive]

Just been through it all with my builder and plumber. Standard digital thermostat is fine as it's just going to be controlling the flow control valve to the underfloor heating

[Ferg]

Be aware that connecting Underfloor Heating to an existing radiator circuit is WRONG!
The Underfloor needs to be on for much longer to maintain the heat. Radiator circuits heat up much quicker than the slab. You should always have a dedicated flow and return to the blending valve and pump and obviously this means using a dedicated channel on a programmer.

[lost in espace]

I would consider having a floor sensor as well as an air one to give you the option. Convection currents can play havoc with air stats. Most stats should be able to accommodate this.