Using a heating thermostat and TRV's

[Jasonpikephoto]

Hi all,

I'm a regular here and ask all sorts of dumb questions and it probably is just common sense. I just have a quick one about home heating temperature thermostats, and the use of TRV's. we have a baby in the home now and just want the perfect temperature all the time.

We have a Myson thermostat with a dial on it, which is located in the hallway, the heat ranges from * up to 35c. Do I set this to max and control each room via the TRV's in each room? If I set it to say between 20-25c, do i then have to adjust the TRV?

[Someone-Else]

Its up to you.

The idea is that each TRV will close when the temperature in the area it is in is reached.
The room stat will switch the boiler off when the hall (in your case) reaches the set temperature.

So If any TRV opens and the hall is at or above the set temperature the radiator will not get hot, but as soon as the hall cools all rads with open TRV's will get hot. (Its also normal for one rad not to have a TRV, its usually the bathroom)

However, I see what you are trying to achieve, but when the timer comes into play, it will switch everything off anyway, and to be honest if you leave the heating on 24/7 you will soon need a 2nd mortgage (Yes you can get room stats that change temp settings according to the time, but I don't think its worth it in this case)

[Jasonpikephoto]

Ah I see your point. Would that explain why the heating suddenly goes off?

I set my TRV in the living room to ||| and it just stops after about half an hour so I just notch it up to ||||. I'm guessing that's when it reaches the temperature and doesn't let it go over?

The thermostat in the hall - it makes a click noise when I turn it to just over 20c, what is this?

[big-all]

just be aware the trvs job is to turn the radiator off and on nothing else
in other words it will not control the heat output the boiler controls that
when the room gets up to heat the radiator shuts off

[Someone-Else]

Ah I see your point. Would that explain why the heating suddenly goes off?

Yes. You will also find it does it the same time everyday. If you were really sad, and stayed up all night you would find that at the same time every morning the heating comes on. The idea is to save you money, since most folk go to bed for around 8 hours there is no point in having the heating on, so the timer switches it of. The room stat switches it on and off as required so long as the timer says it can be on.

I set my TRV in the living room to ||| and it just stops after about half an hour so I just notch it up to ||||. I'm guessing that's when it reaches the temperature and doesn't let it go over?

Yes. That is the whole idea, when it gets to the desired temp it closes. When the temp drops it will open again.

The thermostat in the hall - it makes a click noise when I turn it to just over 20c, what is this?

That is the bi-metalic strip moving from off to on. (Its perfectly normal)
The bi-metalic strip is the sensor in the room stat that detects the ambient air temp, when you turn the "setting wheel" you are infact changing the amount the bi-metalic strip has to move from off to on.

[Jasonpikephoto]

Cool,

Do I keep the bi-metallic strip turned on? 24/7? My heating controller is on 24/7 as is the hot water. I can then adjust the heating via the dial. Am I doing anything wrong? I just want the most economical way to use the heating, and to have a constant flow of heating, not hot, just right.

[Someone-Else]

As I first said, that's up to you.
Its the million dollar question, do you keep the heating on low 24/7 or do you let it turn off for several hour / day. Then when it comes on it has to heat the whole house from cold.

[lockie]

Another important consideration is how good your insulation is.Its all very well to keep having the heating kick in but its just as important to retain as much heat you produce to keep your bills down.

[ericmark]

I also have a Myson and some TRV fitted and also a room thermostat and how one sets it is really dependent on the house.

In my case the Myson thermostat is turned to max. The speed around half way. It is never altered. The down stairs rooms have no TRV's fitted and use the wall mounted thermostat which does not turn the heat on and off but changes the heat according to time of day.

The TRV's in bed room are there to compensate for doors being left open. With doors closed the bedrooms need radiators on but if left open the bedrooms would get far too hot and not the TRV switches off to stop that happening.

But my boiler is an old boiler not condensation type. With the newer boilers the flame hight is controlled by the temperature of the return water. To control therefore you have no option but use TRV as each valve closes the hot water is forced through the radiators in the remaining cool rooms until the pressure is too much and the by-pass valve lifts. When this happens hot water returns to boiler and the boiler first turns down then off. The anti-cycle software in the boiler controls when it will retry. The electric thermostat is only there to stop the boiler running at all in the summer really should be outside or catching morning sun stop stop heating coming on when likely going to be a warm day.

Since the type of boiler makes such a huge difference and even design of house no one can really advise on a forum we can only say what we do.

I have questioned how a Myson will work with modern boiler as it has no TRV fitted the thermostat just turns on the fan. So when it switches off hot water will return to boiler and turn down the boiler.

Since I have a Myson I know what they are. However many may have never seen these radiators and not realise it works like a car heater with a fan and may think the Myson thermostat is fitted to the wall to control whole boiler.

The problem with the Myson is although it heats up quickly it also cools down quickly so any room stat needs to be electronic type so the time between on and off is shorter.

[HeatingSave]

One interesting (albeit not cheap) solution would be to actually replace your existing TRVs with a couple that you can actually program in. There a few such solutions available on the market, some simpler, some more advanced, that enable you to control each of your TRVs, set specific temperatures and functioning times, create heating patterns, etc. Since they pack advanced temperature sensors (a lot more sensitive than regular TRVs), they're significantly more versatile , and you can forger all about manually adjusting them, everything is done via software running on your PC.

[buteman]

Just a few things to consider.

1/ The amount of heat you need to put into a room is directly proportional to the difference between the temperature you want the room to be at and the temperature outside.

2/ The amount of heat you need to put into a room is inversely proportional to the level of insulation provided by the walls. This includes how thick they are and the material they are made of.

3/ The amount of heat you need to put into a room is directly proportional to the number of hours you want the room heated each day.

From these you can usually work out the most economical way of heating the home.
One thing the above rules tell you is that you need to keep the individual room doors closed so you can have different temperatures in different parts at different times of the day.
For example, you might have the heating off completely at night from, say, 11 p.m until 6 a.m.
You might decide it would make sense to have the bedrooms and bathroom warm from 7 a.m until 9 a.m but not for the rest of the day.
In this case programmable TRV's would be needed ( unless you want to get up at 6.30 a.m each day to increase the setpoint on the TRV's and then lower it at 9 a.m )
Similarly you could do the same sort of thing for other rooms simply making sure you only end up heating the rooms you want for as long as you want.
Ordinary TRV's are not able to do this so they are less than ideal. On the other hand programmable one are more expensive.

Hope that helps you to decide.

[wine~o]

What's that smell???

[caravan72]

Hi there, I'm having a room thermostat fitted (programmable) soon, the scottish goverment is paying for it, Ive asked the engineer to leave the programmer free to be moved to any part of the house, he advised he would need to knock off the trv ino the area it's being used but he has been instructed not to, wherever it's used the trv will be left open to accomodate this.
I'm surrounded by many examples of this as the local authority here had to accomadate old folk that complained about the rad that was left with no trv, 'Why is heater still on son' i was at a Danfoss seminar years ago and the guy who ran it, his mother was in a wheelchair, so he fitted the room stat to it! need i say more.

[thescruff]

The point of having a room stat is to provide an interlock for the boiler, it's a no brainer to have it turned right up and not do it's job.

And it's also costing you a bucket load of cash if you do.

[aeromech3]

Jason, I'll never understood why thermostats are fitted in hallway's; it is not the general living area; it is draughty; it is subjected to temperature swings when the door is opened and unless it is an open plan house, is best kept cooler. Having lived with a Reptile for 40 years economy was never the by-word, whether we were in UK or in a Middle East climate we left the room thermostat set for a comfortable temperature, be it heating or air conditioning we hardly ever turned or timed it off, unless the house was vacated as in vacation; we suffered less coughs and colds than we now see in our Grandchildren, so feel that our formlae worked.
Living area 21C +-1C with thermostat, no TRV conflict, then set your bedrooms up to 5C lower by reference to a simple wall thermometer and adjusting the radiator TRV's or as in my house the lockshield.
Hospital nurseries and wards in general are kept at a constant temperature for a reason, you may well choose the baby's bedroom to be warmer than yours necessay for when changing or after bathing etc.
Jason, if you want the perfect temperature for your baby there it is, economy is quite another formulae and you would need to live and sleep in one room to get the best of that.