Radiator hot in summer and cold in winter

[Gibstown]

I constructed a new extension (one room on ground floor) last year with a large double radiator to heat this room. I also installed a new and bigger boiler. This radiator is not air locked and the lockshield is ok. It will not heat up during the winter cold months but is very hot in the summer.
All other radiators in house are ok.
Please advise.

 

[BLOD]

Where did you connect the new rad to ?

 

[Best]

First thought is the pipework is overloaded - too small for demand, or blocked, or just system needs serious balancing. All these will mean the rad may work reasonable in summer but not in cold weather due to the rad & rest of system loosing heat more.

 

[Best]

Where did you connect the new rad to ?

My thought exactly! Often extension rads are stupidly joined to the nearest rad pipes which may already be a bit overloaded for their size.

 

[Gibstown]

Connected new rad to the pipework from a radiator in the adjacent room approx. 4 metres away.

 

[SafeGasInstall]

r u a gas/heating engineer as you mention you installed bigger boiler ?

 

[SafeGasInstall]

if you are then surely you must have heard of pipe sizing

 

[SafeGasInstall]

and welcome to the forum

 

[Gibstown]

Thanks
I think the pipe used was white plastic maybe 10 mm diameter. The rest of the house is 15mm diameter copper.

 

[tamz]

I had a boiler swap last year where some retard had teed the extension rads straight off the flow and return above the boiler. They kind of half worked when on for hw only and nothing when the ch was put on.
Get the system checked by someone who knows what they are doing. It is piped wrong or needs balanced

 

[Gibstown]

Thanks for reply. No I am not a gas / heating engineer. When I built the extension I was advised that the existing boiler was too small for the house. It was 20 kw. The new boiler is 30 kw and uses approx 20 % less gas.

 

[snowhead]

Have all the other radiators in the house got Thermostatic valves on?

Are all the other radiators hot now as well as the extension one, or is it just the extension radiator that's hot?

 

[tamz]

The size of the boiler makes no difference to whether it will work or not.

 

[Gibstown]

Thanks for reply.
Yes all radiators have thermostatic valves. Yes all radiators are hot now and during the warm weather, just the new rad in the extension will not heat up in the winter.

 

[SafeGasInstall]

is it heat only boiler ? the rad you connect the one that do not work is it in your bathroom ?

i think you must have bathroom rad on the hot water side and there fore in summer heats up but will not in the winter as i think you have a y plan

 

[diamondgas]

Has to be piped wrong poorly! If the rad in question is heating as said so will the one you tee'd off unless it's turned off or has a TRV fitted! There's something missing in what your saying IMHO

 

[SafeGasInstall]

if he picked up from by pass rad or rad on hot water side , then in summer will heat up on hot water but winter comes will not heat as heating is selected

 

[Gibstown]

Thanks
My boiler heats the rads and water. The new rad is connected to an existing rad in the living room not the bathroom.

 

[Best]

I bet it is just overloaded. 10mm plastic is a lot smaller bore than 15mm copper & he said it is about 4metre away - that's at least 8metres of 10mm. Add to that the probability of lack of balancing, especially with any rads close to that one. Bet a thermometer would show that rad has low temp even in summer compared with rest.

 

[Gibstown]

Thanks
I think I will need to have a look under the flooring to see how it is piped.

 

[Best]

Thanks
I think I will need to have a look under the flooring to see how it is piped.

If you have the luxury of easy excess to the pipes, then you are lucky you can opt to repipe if needed. If you have the system properly balanced you may find the rad is a lot better, but it is the winter that shows the properly piped/designed systems.

 

[SafeGasInstall]

turn all other rads of and see if this will get hot .....but you say you have combi boiler ?

why will it heat in the summer if is a combi !

 

[Gibstown]

Thanks
I will try a thermometer.

 

[jtsplumbing]

Dont think he told what boiler he has, but did say 10mm to new rad & rest in 15mm, sounds like under sized heating pipe work, when new boiler was fitted was gas supply OK for new boiler ? did you change any other controls, maybe pump is to small or worn out?

 

[Gibstown]

Thanks
The boiler is not a combi. It is a Worcester Bosch Greenstar 30 Di system, for sealed central heating systems and indirect fed domestic hot water, (That what it says on the manual)

 

[Gibstown]

Thanks
Gas supply ok. we added a thermostat control on the wall in the hall, we never had one in the house. I assume the pump is inside the boiler and the boiler in a year old, so i hope is ok.

 

[jam1979]

try running rad in 15mm and by-pass valve may need adjusting slightly