Install Nest for Underfloor Heating

[John Peden]

I've installed Nest for my boiler and have a second unit that I'd like to use for my underfloor heating in the bathroom. The current system was only put in a couple of months ago but I think it was done on a bit of budget and we have a bulky unit, with a crap user-interface that contains the relay within the controller.

Additionally, the electrician wired up a circuit breaker at the foot of the bathroom door as there existing circuit breakers was quite a long way from the bathroom.

The Nest's relay could be hidden out of sight and we'd be left with an attractive controller next to the bathroom light. I'd also planned to move the circuit breaker into the cellar so that it was out of sight.

Is this something that I could potentially tackle or do I have to get a spark to handle anything involving underfloor heating?

 

[AndyPRK]

Do you need to control your bathrooms floor heating remotely

 

[flameport]

What is the rating of the underfloor heating?
The Nest contacts are only suitable for 3A maximum.

the electrician wired up a circuit breaker at the foot of the bathroom door

Picture of this 'circuit breaker'? Do you mean RCD?

 

[ericmark]

Under floor heating control is simply on in winter off in summer, the reaction time is too slow to control a homes temperature using under floor heating. To control the room temperature you need something which reacts far faster.

My son has under floor heating connected to range cooker, so when it runs it warms the floors, which take days to cool down again, but temperature control is done with radiators.

The algorithm required to work out when to switch off under floor heating so the room temperature did not over shoot the mark would be rather complex, at 27°C which is normally the hottest one can run under floor heating at, even if never switched off, you could still live in the home. And if you want 20°C and home is at 16°C to work out at what point to switch off heating would be trial and error, exceed by just 1°C and likely it will take hours for it to fall again.

So the thermostat turns the underfloor off/on so on a warm day it does not come on, but room temperature is controlled by radiators. Under floor heating is just too slow to react. In the main all you need is a time switch, if bath room used 8 to 9 and 17 to 18 hours the under floor heating on 6:30 to 8 and 15:30 to 17 hours. You don't need Nest for that. OK maybe a internet controlled relay so you can alter time running from work, but I know my underfloor heating even left on 24/7 would never keep bathroom warm on it's own, the extractor fan cools the room quicker than floor can heat it, so temperature control is towel rail.

OK with wet room opening onto hall, and hall at 18°C if I want wet room at 22°C then needs a lot of heat, heat raises so if the wet room opened to landing at 20°C then under floor heating would stand more of a chance keeping wet room at 22°C. But same applies, under floor heating is too slow for any normal thermostat to control.

You don't say if the UFH is hydraulic or electric? If a wet system then control current is low so Nest could control it, if electric then you need sensors in the floor to stop floor exceeding the 27°C limit so nest not suitable even if it could handle the power.

 

[John Peden]

Do you need to control your bathrooms floor heating remotely

I suppose not...but I’d like to nonetheless.

 

[John Peden]

What is the rating of the underfloor heating?
The Nest contacts are only suitable for 3A maximum.


Picture of this 'circuit breaker'? Do you mean RCD?

Amperage might be a limiting factor. I’ll have to check.

Yes it’s an RCD. I called it an RCBO and a spark corrected me so I wasn’t sure.

 

[John Peden]

UFH is electric so maybe a non starter anyway?

Temp of the room is controlled by a rad/towel rail.