How hot can your house get?

[StudWall]

So today i thought i'd do an experiment and crank my heating up as high as it will go and see how hot my house actually gets (thermostat set to 30c)

I've noticed before that the radiators get hot fast and kick out heat, but it seems to take an age to heat the room up.
When i replaced the radiators from single slab to double convectors, i used an online calculator to work out how many BTUs i need, ignored it, and got the biggest one that would fit in the space.

Here's what the calculator said and what i bought:

Calculated / bought (BTU)

Bedroom 1 - 4250 / 6800
Bedroom 2 - 3100 / 5200
Hall - 4000 / 6100
Bathroom - 1700 / 620
Kitchen - 4000 / None fitted
Living Room -10750 / None fitted

so, the hallway only got to about 17c but as the bathroom is underpowered and that and the living room & kitchen are off the hallway, i can understand that all of it's heat is probably escaping into the other rooms, however i closed off the 2 bedrooms and after 5 hours they only got to 21c (bedroom 1) and 23c (bedroom 2).

All the TRVs were set to maximum, i can't quite understand why the 2 bedrooms don't get above those temperatures, i would probably never want it that hot, but would have thought it would get hotter especially after 5 hours being on constantly, windows closed, curtains closed and loft above each room insulated and double glazed.

any ideas??

 

[nortonj]

Where's your room stat?
What's the flow temp set to on your boiler?

 

[StudWall]

room stat is in the hallway next to the bathroom door.

Boiler is also set to max

 

[nortonj]

Does the hallway radiator have a trv or standard lockshield?

 

[StudWall]

the one in the hall just has a standard lockshield, same as the bathroom, the 2 in the bedrooms have TRVs

 

[nortonj]

Was thinking maybe the lockshield not fully open so rad not getting hot enough to heat the space. Or the flow temp on boiler not hot enough, I know it's on max but maybe it's not putting out the 80 degree flow temp due to an underlying fault. You would need to measure temp of flow pipe near boiler

 

[StudWall]

Good thinking but I only balanced the radiators a couple of months ago, iirc the flow was about 71c

 

[D_Hailsham]

What boiler do you have and what's its output (kW please, BTU are like £sd )?

How are the kitchen and living room heated?

 

[StudWall]

kitchen is currently not heated, living room heater by wood stove.

boiler is potterton profile 50e - 11KW

 

[kidgreen61]

Did you close the doors and windows?

 

[StudWall]

yes they were closed.

I wonder if it is because there isn't enough radiators on the boiler for the KW output and it is cycling quite fast, every 4-5 mins

 

[xr4x4]

What speed the pump on?

 

[StudWall]

Pump is on 2

 

[D_Hailsham]

boiler is potterton profile 50e - 11KW

The standard output of the 50E is 14.65kW (50,000BTU). Has the output of the boiler been turned down to 11kW?

The rads only add up to 5.5kW, so the boiler is giving out twice what the rads can use. The system will be cycling all the time.

Even if you keep the kitchen and living room doors closed, there will still be heat lost into those rooms.

Do you know how large a boiler is needed to heat the whole house? Use Baxi Whole House Boiler Size Calculator to find out. Obviously you need the rads to add up to the same output.

 

[StudWall]

I'm not sure if the boiler has been turned down, I just thought 11kw was correct, not sure why.

I've just fitted another 2kw radiator, to the living room so ill get that attached over the next few days and see if there's any improvement.

The baxi website calculator gives me 10kw