should i have a room thermostat with my combi boiler.

[baileys]

ok thanks, i understand that now.

So would i be able to control the heat i want in my house better if i had a room thermostat.

 

[Mike Jackson]

So would i be able to control the heat i want in my house better if i had a room thermostat.

The room thermostat will ensure that the boiler doesn't keep running when the temperature rises but fine control should be with the TRVs.

It doesn't sound to me like the operation of your system has been very well explained to you. A TRV does not vary the temperature of the water in the radiator. Think of it like an off switch that turns the radiator off when the room reaches a certain temperature. When the temperature drops below that temperature the valve opens and the radiator will get hot again.

It normally takes a little while to get the system set up as you want it but don't keep turning TRVs up and down as this defeating the object of having them. I generally set them to 1 or 2 in bedroom areas, 4 in living areas and 5 in bathrooms and advise the customer to tweak them over a period until they get the temperature they desire.

 

[lame plumber]

combi stat costs b all more than a decent trv!

 

[Worcester]

It's been inthe regs since 2002, so it must be already included in his quote

For umpteen years, good heating engineers have been fitting roomstats to control heating systems.

Each room has a design temperature. Living room 20 degrees C, hall 18, bedroom 16 and bathroom 25. Heat loss is calculated with these temperatures. Therefore a radiator fitted in the lounge will maintain lounge temperature at 20 when external temperature is at -1. It follows that a roomstat fitted in the hall and set to 18, will switch the boiler off when the hall reaches 18 degrees. By this time, the lounge will be at 20, bathroom at 25 and bedrooms at 16. Same roomstat if fitted in the lounge would be set to 20.

While a roomstat will shut a boiler down (conserving fuel), TRVs will stop taking heated water but fail to tell the boiler that it should stop. Meanwhile, the boiler has now to rely on its own stat to shut down. It keeps firing every so often to maintain the set boiler temperature.

If the TRVs are used alongside a roomstat, rooms that are naturaly warmer (say south facing), shut down by the TRV. Colder rooms continue to heat until the roomstat (hopefully fitted in one of these rooms) switches off the boiler.

If the radiators are oversized, guestimated or not balanced, the roomstat will get erroneous readings and by unable to function correctly.

Invite your engineer to carry out heat loss for the rooms and see if he is able to do that, if not choose someone else..

Modern digital roomstats can control room temerature to plus minus 0.5 degree

 

[baileys]

It's been inthe regs since 2002, so it must be already included in his quote

For umpteen years, good heating engineers have been fitting roomstats to control heating systems.

Each room has a design temperature. Living room 20 degrees C, hall 18, bedroom 16 and bathroom 25. Heat loss is calculated with these temperatures. Therefore a radiator fitted in the lounge will maintain lounge temperature at 20 when external temperature is at -1. It follows that a roomstat fitted in the hall and set to 18, will switch the boiler off when the hall reaches 18 degrees. By this time, the lounge will be at 20, bathroom at 25 and bedrooms at 16. Same roomstat if fitted in the lounge would be set to 20.

While a roomstat will shut a boiler down (conserving fuel), TRVs will stop taking heated water but fail to tell the boiler that it should stop. Meanwhile, the boiler has now to rely on its own stat to shut down. It keeps firing every so often to maintain the set boiler temperature.

If the TRVs are used alongside a roomstat, rooms that are naturaly warmer (say south facing), shut down by the TRV. Colder rooms continue to heat until the roomstat (hopefully fitted in one of these rooms) switches off the boiler.

If the radiators are oversized, guestimated or not balanced, the roomstat will get erroneous readings and by unable to function correctly.

Invite your engineer to carry out heat loss for the rooms and see if he is able to do that, if not choose someone else..

Modern digital roomstats can control room temerature to plus minus 0.5 degree

This is exactly how i thought it worked and sort of how i tried to explain it to my plumber but he said that the room i have the roomstat in will turn all the heating off when it may be needed in another room.
I see now that its about getting the balance right. I will get someone to fit one because i expect it will save me money too if the boiler is not firing all the time.

 

[julesverne]

your plumber doesnt know what he is talking about. and to be frank i would ask to see what qualifications he has to have the right to call himself a plumber because he is giving you very bad advice. as said already a thermostat is needed to comply withbuilding regs.

why not post up in the looking for an engineer section. there may be one of us nearby who wil give you better advice.

Also get onto the GSR who fitted and hassle him for the cert and check the benchmark section has been filled at the back of the boiler manual/instructions.

 

[baileys]

your boiler requires interlock between its controls to operate efficiently and meet the building regulations. the cost of a room stat will be saved on your bill within one year, two at most. £15 for a stat, £5-£10 for cable and consumables, an extra hour or so in labour time if hes competent to fit one.

Ive checked the manual book that he has filled in and he has ticked the box...boiler interlock.. so does that mean he is saying that he has installed a room stat and not just the thermostatic valves on rads?

 

[Worcester]

Here's the Good Practice Guide :

[DLMURL]http://www.draytoncontrols.co.uk/uploadedFiles/Drayton/Industry_Regulation/Good_Practise_Guide_302_ENG.pdf[/DLMURL]

Check out the top of page 8.

n.b. don't put / remove any trvs on the radiator(s) in the same room (or hall) that the room thermostat is.

 

[Nostrum]

Ive checked the manual book that he has filled in and he has ticked the box...boiler interlock.. so does that mean he is saying that he has installed a room stat and not just the thermostatic valves on rads?

I would say yes, is it signed Mickey Mouse at the bottom as well?

 

[Ermintrude]

Here's the Good Practice Guide :

[DLMURL]http://www.draytoncontrols.co.uk/uploadedFiles/Drayton/Industry_Regulation/Good_Practise_Guide_302_ENG.pdf[/DLMURL]

Check out the top of page 8.

n.b. don't put / remove any trvs on the radiator(s) in the same room (or hall) that the room thermostat is.

Nice guide! It's a few days old looking at the energy saving trust logo?