Madness having no room thermostat?!?

[GeoffLondon]

I've just moved into a flat with a Vaillant ecoTEC pro combination boiler.

Picture of boiler

• GeoffLondon
• 10 Mar 2011
• 1

Vaillant ecoTEC pro combination boiler

I was astonished to learn that the system has no room thermostat, however apparently the radiators all have "thermostatic radiator
valves".

Additionally the boiler has a knob called the "maximum radiator temperature control" that makes the overall system run hotter or cooler. I control it by raising or lowering that.


I have 3 concerns:

1. some parts of the flat are real warm, and some are real cold. How difficult is it to adjust these radiator valves individually to get more even heating? Any tips about doing that?

2. is this a sensible setup? Seems slightly mad to me. Without an actual room thermostat, how does the central heating know when to ignight?

3. I notice in the installation guide that it seems easy enough to add a room thermostat. Should I? What's the gain? For example: Am I wasting energy by not having a proper thermostat?

Wiring diagram

• GeoffLondon
• 10 Mar 2011
• 1

Wiring diagram for Vaillant ecoTEC pro combination boiler

The boiler installation guide is available http://www.vaillant.co.uk/stepone2/data/downloads/d7/42/00/ecotec-installation-and-servicing.pdf

The boiler user manual is available here http://www.vaillant.co.uk/stepone2/data/downloads/19/43/00/838402_06.pdf

Thanks for any thoughts!

Geoff

 

[Agile]

The idea is that you control each room by the thermostat radiator valve.

But they take up to 40 min to take effect.

You should have a room stat to turn off the boiler. Its required under the Building Regs when a new boiler is fitted.

Is this rented?

Tony

 

[bengasman]

Am I correct in presuming you have not read the faq?

 

[GeoffLondon]

Hi Tony,

Thanks for that.

When water circulates through the system I guess I can see how the boiler could have some feedback about the relative temperature out in the room, but it wouldn't really. It would just see the temperature of water circulating back in. Doiesn't seem like it could be very accurate.

Why does it take 40 minutes? When I turn up the radiator temperature control in the morning, the boiler runs about 5 or 10 minutes and then stops, and then runs again about 15 minutes later for another 5 or 10 minutes.

Yes it is a rented flat, and the owner is open to having the boiler serviced, and a room thermostat installed at the same time, so I want to understand the system so I can ask for the right things.

One thing I read in the manual is that where the room thermostat is positioned, there should not be a TRV ("thermostatic radiator valve") on that radiator in there.

Are you suggesting I should ask for a thermostat to be fitted? If you know, what's a good wireless job?

 

[GeoffLondon]

Hello bengasman,

Thanks for asking. Yes, the FAQ had some good information about balancing a central heating system, but doesn't offer a judgement about whether such an arrangment is recommended, or not.

Getting the judgement of experts is the main aim of my post. Would you want to have no thermostat in your home?

Thanks,again,
Geoff

 

[JohnD]

I am a householder not a pro

If you are going to the trouble and expense of having a thermostat fitted, I would go for a Programmable one. This will cost £40 or so, unlike a bog-standard wall stat at £12 or a Wireless stat at £120.

A programmable stat allows you to set different temperatures at different times of day and days of the week, and also (usually) enables you to tell it you are going on holiday for nn days, whereupon it will run the heating very low until the day before you return, when it goes back to normal and gets the house warm for you.

My suspicion of wireless stats is that they are one more thing to go wrong, and less easy to test when they do.

 

[bengasman]

Getting the judgement of experts is the main aim of my post. Would you want to have no thermostat in your home?

I consider a roomstat vital, and especially a programmable model will greatly enhance comfort.
A roomstat will also save you some money, and eventually pay for itself.

 

[ajrobb]

I agree with JohnD, a programmable thermostat for me every time. This gives some control over the whole home. If you still find you are fiddling with TRV settings during the day, you can get programmable heads to fit most TRVs for about £30 a pop. If you keep the old TRV heads, you can put them back and take your programmable heads with you.

As you say, the radiator in the room should be controlled by the new room thermostat and not the TRV. I think the room thermostat needs to be at least 1.5m off to the side of any radiator.

 

[GeoffLondon]

Hi Tony,

You should have a room stat to turn off the boiler. Its required under the Building Regs when a new boiler is fitted.

When did that building regulation come into effect? My understanding is that the boiler is only 2 years old.

Is this rented?

The landlord lived in the property two years ago, but it's rented now to me.

Thanks,
Geoff

 

[D_Hailsham]

You should have a room stat to turn off the boiler. Its required under the Building Regs when a new boiler is fitted.

When did that building regulation come into effect? My understanding is that the boiler is only 2 years old.

It was in the Domestic Heating Compliance Guide published in 2006.

To be pedantic the Guide does not specify a room thermostat but a boiler interlock, which it defines as controls wired so that, when there is no demand for heating, the boiler is switched off. In the majority of cases this means a timer/programmer and a room thermostat. But there are boilers which have flow sensors incorporated which turn off the boiler when the flow reduces due to TRVs shutting down.

The landlord lived in the property two years ago, but it's rented now to me.

Did the landlord provide you with a Gas Safety Certificate showing that the installation has been tested by a Gassafe registered engineer? This is a legal requirement and a new certificate has to be issued every year.

 

[GasNewb]

Room thermostats are normally always placed in the coldest part of a property, which tends to be the passage way. One of the benefits to it is that it can be set to a desired temperature to heat the space its placed in. However one thing that people find is that having the stat set to 21 degrees for the passage way and sitting in the living space with the electrical heat dissipating components and body heat seems to have the living space toastie before the passage way even reaches its set temp. One simple thing to do, is have the thermostat temp set a few degrees less than 21.

If this is fitted in your living space then you'll have the reverse effect, in that the thermostat will turn off your heating when other parts of your home may still need/want it.

As for building regs. Building Regulations Section L 2002 that a minimum level of controls are fitted to heating installation for both new build and renovations. The minimum being; a time switch, control interlock (which can be stat, flow switch etc, TRV's on all radiators besides the space with the room thermostat, if thats not possible then at least trv's in the sleeping areas.

If your boiler has an integral flow switch then thats the control interlock and sufficient enough.

This is my understanding of it, i'm sure someone will correct me should i be wrong.

Hope that helps though.

 

[bengasman]

Room thermostats are normally always placed in the coldest part of a property...

I take it you are so new to gas that you have not quite done your energy efficiency certificate yet, or studied the CHeSS.
There is literally not one correct bit in that entire statement.

 

[GasNewb]

Yes still young and very new to gas. Hence my, "I'm sure someone will correct me should I be wrong". Havent got my energy cert yet nor studied CheSS either. Still got lots to learn!

 

[bengasman]

Clearly.
Have you got your registration? If so, get into cc; the best education anyone in gas could possibly wish for.

 

[GasNewb]

Yep got the registration and joined cc earlier last week. Slowly but surely it'll all sink in, me hopes!