Radiator Balancing/Central Heating Advice

[wizzer]

Our central heating system has never been brilliant. The house is 45 years old and most of the system is original. Downstairs, CH pipes are buried in concrete floor.

We had a new boiler installed 4-5 years ago and that improved things a lot but not perfect. Radiators upstairs get piping hot but always seemed to struggle to get enough heat downstairs in living room etc.

Had problems with pump failing etc and British Gas (we have service contract) say it needs a powerflush. However recent visit by private plumber (see below) seems to think not.

We have recently had living room redecorated and had two new radiators fitted with TRV's. They work very well on the whole, I have tried to balance the system and they certainly seem to get hot first and to a reasonable temperature although not really piping hot.

Trouble is for example, they heat up very well first thing in the morning but later on they seem to switch off (or at least the heat output is low i.e they are only warm to touch even when the room thermostat (which is in the hall) hasn't clicked off whilst the other radiators (most of which don't have TRV's) just get hotter and hotter.

The fitter has said that the system either needs more rebalancing or alternatively I should have TRV's fitted to all the rads.

I've tried rebalancing the other rads and on most of these I've closed the lockshield valves down to no more than a quarter of a turn but they still get incredibly hot. To my mind the boiler must be working really well producing very hot water if it can raise the temp of the rad (eventually) with the valve open so little.

So the boiler and system seems to be working quite well - I just can't get the heat to where I really want it most of the time.

Any suggestions please?

Thanks

 

[herp_lee]

Fit Trvs on all your rads apart from hallway where room stat is. Possibly the wrong kilowatt boiler fitted in. Possibly pump. Possibly incorrect balancing of the system.???? You need to consider these possibilities and get a gas safe registered engineer to identify the problem and fix it for you. Hope this helps.

 

[doitmyself]

We had a new boiler installed 4-5 years ago

Make, model, kW output?

Radiators upstairs get piping hot but always seemed to struggle to get enough heat downstairs in living room etc.

Turn off all upstairs rads. Do the downstairs ones now get hot? If they do, it's a balancing problem.

They heat up very well first thing in the morning but later on they seem to switch off (or at least the heat output is low i.e they are only warm to touch even when the room thermostat (which is in the hall) hasn't clicked off whilst the other radiators (most of which don't have TRV's) just get hotter and hotter.

Are you talking about the rads with TRVs? If so, that's just the TRV working.

The valve will be fully open while the room is being heated from cold. When the room temperature is about 2C below the required temperature the valve will start closing, reducing the flow and therefore the rad temperature, until it reaches a point where the output from the rad is just sufficient to maintain the correct room temperature.

 

[petertheplumber]

This is an attempt at detailing the balancing of rads I hope it helps but if not get someone to do it for you:-
Balancing radiators.
(1) As a first step close any rads that are getting hot and see if that heats any of the other rads. You can quickly work out which rad heats first by letting them all get cold and when they start heating up find out which pipe gets hot first, use the pipe temp to test rad for heat it is quicker than waiting for the rad panel to heat up.
(2) The radiators that are nearest the pump are usually getting hot first.
First make sure system is on heating only no hot water and any bypass if fitted is closed.
(3) If they have a lockshield valve one end and a hand control valve the other end, make sure hand control valve is fully open and then closed just a touch. Close the lockshield valve with a small spanner on the flats of brass shaft exposed when the plastic knob is pulled off, then open it 1/8-1/4 of a turn.
(4) If there is a trv then make sure they are all open and the pins are up not stuck down.
(5) Then move to rad that is next one from pump and repeat, and so on until you are downstairs then open lockshield valve ¼ -1/2 a turn. By the time a valve is open by 1 turn it may as well be fully open.
(6) That should work all rads. Then open bypass valve to same position it was in. If you manage to get all the rads working, once the hot water starts heating it will unbalance the rads so set the programmer to heat the hot water continuous or hot water 1.5 hrs before heating.
Good luck