Thermostatic Radiator Valves (TRV's) & central thermostat

Norman_Castle

I would of thought that not having a thermostat will cost you more money because the boiler will be running for longer periods and never switching off until the timer turns it off.

The boiler will switch on and off according to water temperature.

mefifi

diywhynot wrote: »

Honeywell CM 927.

Thanks. Do I need to buy a receiver bit for the boiler as well? Or does this include it? (Yes, I am clueless!)

diywhynot

mefifi wrote: »

Thanks. Do I need to buy a receiver bit for the boiler as well? Or does this include it?

Includes it.

tired_dad

Interestingly I'm in a similar position.

Old conventional boiler (thorn) with a single dial (0-10). I presume this dial controls the temperature that the boiler heats water to.

There is a pump with 3way valve controlling the central heating and hot water.

All the rads bar the hallway have trv's.

My logic was that the trv's restrict heat output in each room to the required setting.

Therefore if the boiler dial is set highish, the trv's will take care of the rest.

I am finding it difficult to understand what 'real terms' difference investing in a room stat will make.

Perry525

Fitting a room wireless thermostat is simple and takes a few minutes.
I have two Danfoss thermostats, one is in whichever room I am in, the other is in our bathroom.

Having two or more wireless thermostats along with radiator thermostats gives you economy and comfort.

You may like to consider that rooms on the south side of a home will be hotter than those on the north side, north side rooms will probably feel cold at times as radiator stats merely stop the room from becoming too hot, but cannot call for heat. Having mobile wireless stats help with this problem.

Most fixed stats are on a wall five feet up in the air at a point where it is warmer, having the wireless stat beside you on a coffee table is better because that is where you are. Walls are normally at air temperature or colder this has an effect on your comfort.

Having the radiator stats at high level increases the radiator output by 15%.
Just remember to turn the radiator thermostats full on in the rooms where the wireless stats are working.

jennifernil

The purpose of the room stat is to turn off the boiler and pump when heat is not called for in the area the stat is in.

When you only have TRVs the boiler will turn off when the TRVs close down and the water returning to the boiler is above the temperature set on the boiler thermostat, but the pump will run continuously and circulate the water in the pipes. This is deemed to be wasteful.

Being able to turn everything off completely is called "boiler interlock" (I think), and is supposed to save money.

Personally, although I can see you would use less fuel, I am not convinced that it is going to be entirely satisfactory in operation. If you have a wireless stat that you move from room to room with you, that room will be fine, but it decides when the other rooms can get heat.

If you have a room that needs more heat according to its TRV, it will only get it if the stat is also calling for heat. I cannot see how that is satisfactory.

We have TRVs, we have one radiatior without a TRV as a "bypass".
This is in the hall, the rad is relatively small, so the hall never gets very warm. This is fine, we only pass through the hall now and again.

When we need a new boiler, we will also need to fit this room stat. I would get a wireless one and leave it in the hall somewhere away from the rad. If I set it to say 18 degrees, it would never turn the heating off as the hall doesn't get that warm. My TRVs will continue to operate as before, so nothing will have changed. Apart from hopefully I will be saving some money as my new boiler SHOULD be more efficient.

However, to fit a new boiler is going to cost me, say £2000 + , going to take maybe 10 years to break even, by which time the boiler will probably be needing replaced again.

I am hanging on to my 25 year old boiler as long as possible!

southcoastrgi

Woooooooooooo Hoooooooooooooooo

Jennifer you deserve a massive :T:T for that post

knightstyle

If your fuel bills are high think about why? An airtight well insulated house needs no extra heating! Use an air/air heat exchanger to keep oxygen levels up.
You will only need to heat water and you will get enough heat from the lights, people and cooking. So look at where the heat goes, it may be worth hiring an IR camera and film the outside of the house.

blogger57

The TRVs on our system are great but the position of the wired themostat upstairs on the landing is a pain. We had our loft insulated recently so where the thermostat is now gets warm quite quickly - the heating switches off even if some of the other rooms aren't warm enough.

It's more of a problem later in the evening as the heat tends to build up and we find ourselves having to turn the thermostat up to ridiculous levels just to activate the heating to get the other rooms warm.

I would certainly go for a wireless thermostat to allow it to be put in a more sensible position. It would be good to know if there is a better way of positioning the thermostat - we have it on the landing at the moment.

Perry525

You can get round this by moving the thermostat to your living room or bedroom.
Thermostats use very little electricity, so running a semi transparent wire from the current position to your bedroom or living room should not present a problem.
It is always a good idea to have your living room and bedrooms on separate loops controlled by motorized valves and room thermostats.