Confused by 2 thermostats :-/

[Roger465]

So I’ve just had my old heating system updated from having only the little knob on the boiler to turn the overall heat up and down, to now having a room stat as well.



But obviously I can still turn the boiler knob up and down too… how does that work? I’d have thought there should only be one stat in the system?



Thanks

 

[ianmcd]

The thermostat on the boiler controls the temperature of the water within the system (or how hot the radiators will get if you want to think of it that way) The room thermostat is activated by the temperature of the air in the room it is installed in and will switch the boiler off once it is satisfied.

 

[Roger465]

Thanks – yes, I get that, but then, presumably, if I turn the boiler stat down, it will simply take longer for the room to get up to the temperature which will turn the room stat off – if I turn the boiler stat way up, the rads will come up to temp quicker, and turn the room stat off sooner…



So, either way, same result as regards the temperature of the room…?



So what should l do!

 

[terryplumb]

Think of it this way ,if you did not have a room stat ,the boiler would keep on working as it does not know that you are too hot ,until you turn it off. Then temp drops ,you go cold and put it back on. The wall stat negates that. So set your boiler stat to as low a setting as it takes to get your house to a comfortable level ,in a reasonable time frame.by a bit of trial and error. And use wall stat to govern.

 

[Roger465]

So set your boiler stat to as low a setting as it takes to get your house to a comfortable level ,in a reasonable time frame.

Yeah that's the bit I wasn't sure about really. Thanks

 

[John D v2.0]

Agreed with Terry. Bear in mind your boiler is 10% more efficient with the gas if you turn the boiler temperature down. But if you turn it down too far your house will cool faster than it warms.
We try to control the temperature of the house by adjusting the boiler so ideally it never goes over the set temperature.

 

[Roger465]

Bear in mind your boiler is 10% more efficient with the gas if you turn the boiler temperature down.

Thanks – yes, I read various articles on energy saving websites latest last night, where I learned that the condensing feature of the boiler doesn't work if the returning water is too hot. Logical really, now it’s been pointed out.


Actually, when the new boiler was first put in, I had it on the lowest setting, and it warmed the few rooms I heat fine, albeit a bit slow… Guess I’ll just have to mess about with it till I get the lowest setting that’s compatible with actually heating the place.


Another thing which caused my brow to furrow was the plumber’s insistence that the room stat should be in the coldest part of the house, with everywhere else governed by TRVs… whereas I wanted it to be in the living room, where I… live. I don’t really want to heat my big long bungalow hallway up much.


But we couldn’t see a way of getting it in here without digging a big track down through the cornicing and wallpaper, which you can't get any more – so I agreed to put it in the hall for now, and change over to a wireless one in here once everything's settled down and the grant has been paid for all the work (they won’t pay if you don’t do it their way, which is not the wireless way…).

 

[Roger465]

PS incidentally, my cousin (a builder) is always extremely canny with money, so sits down and works everything out to the last penny, but is also cold in his freezing old cottage… he has worked out what he believes to be the best compromise between warmth and economy.



He has the same condensing boiler as me (we’re both on oil, sadly – no gas available), and runs it quite low. However, in his bedroom he has a fan heater which comes on at the same time as the boiler, but only for a short time (I think ½ an hour or less). So the bedroom comes up to temperature very quickly in the morning, then the rad maintains it.

 

[John D v2.0]

Another thing which caused my brow to furrow was the plumber’s insistence that the room stat should be in the coldest part of the house, with everywhere else governed by TRVs… whereas I wanted it to be in the living room, where I… live. I don’t really want to heat my big long bungalow hallway up much.

The plumber is following conventional wisdom, bear in mind the thermostat doesn't warm the room it's in quicker, or make the other rooms cooler or warmer if they have a trv. Its only job is to cut off the boiler when the whole house is probably not in need of heat any more.

 

[Phill Peck]

Consider if you have a hw cylinder then setting the boiler thermostat very low could result in
A- insufficient hot water temp
B- legionella growth as a result of A

 

[Roger465]

Consider if you have a hw cylinder then setting the boiler thermostat very low could result in

A- insufficient hot water temp

B- legionella growth as a result of A

That was to be my next question! I’d been planning to leave the hot water permanently switched off, as I have an electric shower, and dishwasher, so never use any…



I wonder if that would be OK, and maybe heat the tank quite hot every so often to kill any little blighters…?

 

[FiremanT]

That was to be my next question! I’d been planning to leave the hot water permanently switched off, as I have an electric shower, and dishwasher, so never use any…

Wow! You always shower after visiting the bathroom?

 

[Roger465]

Wow! You always shower after visiting the bathroom?

Err... a little off-topic, perhaps, but if you're that interested, I wash my hands in cold water. I think you'll find that's OK from a hygiene point of view.

 

[FiremanT]

If

Err... a little off-topic, perhaps, but if you're that interested, I wash my hands in cold water. I think you'll find that's OK from a hygiene point of view.

If you say so. But I won't be calling for dinner any time soon

 

[aptsys]

If


If you say so. But I won't be calling for dinner any time soon

If you can wash your hands at over 60°C then good for you... Below that temperature, warm water does nothing for hygiene.