Combi Boiler flow temp

J30

Hi,
Over the summer I moved in to a house, that is very old (built around 1910) 

At the moment in this really cold weather we are having I am finding it very hard to heat up. 

It is a combo boiler and the house isn’t reaching its target temperature. 

I have kept all doors in the house shut but I am struggling to get the heat up. 

For example - I could set the thermostat to 19 and it won’t go beyond 17 or 17.5 - therefor the boiler is just going to keep going and going and going.

it is an A efficiency boiler - only 5 years old. Recently been serviced too. All in excellent condition. 

But wish I could get the house to my target temperature! 

What’s peoples thoughts on flow temperature. Mine was set to 60 so I have just turned it up to 70. Is this likely to help? Will this help heat the house quicker? 

There is loft insulation but think it’s really old. Just been up there and it’s absolutely freezing - but I am sure most lofts are. 

Any support / advice would be greatly appreciated. 

Have applied for the great British insulation scheme but I expect to be waiting a while! 

EssexHebridean

The loft being freezing is a good sign - at least you know all your heat isn't escaping up there!

What age are your windows - might they be causing heat loss? 

J30

EssexHebridean said:

The loft being freezing is a good sign - at least you know all your heat isn't escaping up there!

What age are your windows - might they be causing heat loss? 

Not sure about the age, but they all in really good condition. All double glazed. 

Just struggling at the moment. The thermostat sensor isn’t reaching its target temperature so the boiler is constantly trying to get the temperature up. Instead of reaching temperature, and then turning off. 

Going to cost an absolute fortune 😩 

sammyjammy

Is there a separate thermostat?  Where is it placed? My house is a Victorian terrace built in 1899, there is limited options re insulation to be fair unless you want to spend £££.  Is the loft a habitable room?  Is there no radiator if it is?

J30

sammyjammy said:

Is there a separate thermostat?  Where is it placed? My house is a Victorian terrace built in 1899, there is limited options re insulation to be fair unless you want to spend £££.  Is the loft a habitable room?  Is there no radiator if it is?

The thermostat is a portable one, just got a Drayton wiser. So I can put it in any room and the sensor will turn the boiler on and off as required - and that controls the whole house. I have tried moving it around the house to see if other rooms are warmer and they are all about the same. 

Loft isn’t in use. It’s been insulated and boarded but isn’t in use. 

born_again

Are the rooms getting warm, with doors shut?
Are radiators getting hot do they have the TRV on & is the pin free?
Where is stat in relation to house?

Try leaving doors open to let heat circulate around the house to build a base temp if rads are all getting hot.

barbuda

Hi,
it all depends on what you want...if you want to be warm, turn the boiler stat to max and let the room thermostat or trv's monitor the house for you (as long as the radiators are correctly sized).
If you want to save money, turn the boiler stat down, but the room stat or trv's may never reach the desired temperature...

J30

barbuda said:

Hi,
it all depends on what you want...if you want to be warm, turn the boiler stat to max and let the room thermostat or trv's monitor the house for you (as long as the radiators are correctly sized).
If you want to save money, turn the boiler stat down, but the room stat or trv's may never reach the desired temperature...

It’s a difficult one. I want to save money but also don’t want to be freezing. Normally the boiler is set to 60 but as it’s in minus temperatures outside I have temporarily turned it up to 70 to see if that will work. 

FreeBear

Check the depth of the loft insulation - Current recommended level is around 300mm. But anything over 200mm is good.

Running at a 70°C flow temperature, whilst not the most efficient, will mean more heat getting to the radiators if they have been balanced properly. Also worth checking that the radiators are properly sized for the rooms. This calculator will give you some recommended sizes - https://www.stelrad.com/basic-heat-loss-calculator/ - Run the calculations again with a lower ΔT (say 40°C), and that will give you an idea of what will work when using a lower flow temperature.

J30

barbuda said:

Hi,
it all depends on what you want...if you want to be warm, turn the boiler stat to max and let the room thermostat or trv's monitor the house for you (as long as the radiators are correctly sized).
If you want to save money, turn the boiler stat down, but the room stat or trv's may never reach the desired temperature...

This is the problem. The radiators are blazing hot. But the rooms just aren’t reaching the desired temperature. So turned the flow up from 60 to 70 as it is minus temperatures outside. Once it is mild again I will reduce back to 60. 

Normally it’s not too bad in milder conditions. It’s just in this really cold snap we are having the house is struggling 

PRDMKT

My first port-of-call would be the thermostat, not the boiler.

Standard rule of thumb, the thermostat should be in a commonly used room, such as your living room with a radiator nearby (and not TRV present) a.k.a that radiator should always run in-line with the boiler. 

#1 Does the house feel hotter than the thermostats reading?
#2 Is the thermostat in a room which feels as hot as the rest of the house? 
#3 Are your radiators getting hot? or is there a possible airlock? (they might just need bleeding)

Occam's razor, I would expect a simple answer will solve this one

Good luck