Problems with new condensing boiler

[Chrisbainbridge]

Hi, first post so apologies if technical language is wrong!

background: last 20 years we have had a 5 bedroom house with a boiler that was new 20 years ago. Separate hot water and radiator circuits. All radiators heated quickly and were of an even temperature top to bottom and inlet to outlet (roughly).

new build house, 3 zones with room stats, 2 underfloor heating areas. Condenser boiler.

only one radiator in the house is an even temperature from top to bottom, the majority are hot at the top and cold at the bottom. Some even after the heating has been on for 12 hours are not properly warm at the top.

the main bedroom has the radiator that is an even temperature but the other radiator in the room barely reaches warm after the heating has been on for 12 hours. I have checked all the TRVs and they are all open. I have even taken the TRV off and left them open.

centre of the house is warm but several of the rooms never get above about 10-12 degC over the weekend.

I measured the temperature of the inlet and outlet valve metal bodies on a few radiators with a type K thermocouple I had. Inlet temperature was 50-52 and outlet was 25-27.

Are these findings normal for a condenser boiler or should I be asking the builder some questions? I don't want to hassle if this is just a new heating system I need to get used to.
thanks
chris

 

[doitmyself]

new build house, 3 zones with room stats, 2 underfloor heating areas. Condenser boiler.

If it's a new build and therefore covered by a 10 year guarantee, you should get the builder back and get him to sort it out.

From your description, it would seem as if the system has not been balanced. This adjusts the flows so each rad gets its fair share of the heat produced by the boiler.

An easy way of checking is to find out how far the lockshield valves are open. They are the valves at the other end of the rad from the TRV. There is usually a plain cap which can be pulled off to reveal a spindle which can be turned with a pair of pliers.

Turn the spindle clockwise (looking down) and count how many turns until it stops. If more than one, the rad has not been balanced. If less than one, an attempt has been made to balance, but not very successfully. Don't forget to set the LS valves back to the original position, so the builder sees it 'as is'.

Which boiler do you have?

 

[glenno1]

Turn couple of rads off and see if the others perform better this will show possible poor balancing also

 

[AWheating]

as a very general rule the rads nearest the pump will need to be closed down a fair bit (1/4 open)on the lockshield side and as you get further away/longer pipe lengths your will want the locksheild valve open more (fully open). its also normal to have the upstairs rads closed down alot more than the downstairs rads.

personally id get the builders plumber back to sort it out.

im assuming your room stats are not near radiators and in rooms with no trvs?

 

[stevetheplumber]

those that are cold at the top probably need bleeding buit does sound like it needs balancing

 

[Chrisbainbridge]

Hi, thank you for all your replies.

Steve, sorry I wasn't clear. None of the radiators are cold at the top, they are warm at the top and cool at the bottom.

i have got back onto the plumber and he is coming tomorrow to balance the system! This is despite telling me that it was all sorted and nothing more to be done!

i am very grateful for the advice. Chris