Radiator heating problems - please help!

[snaver]

Hello, can anyone help me please? (apologies for the layman's terms in places, but I hope you can understand what I mean). We had a new radiator installed today by a reputable plumber, as the old one had slush and would no longer heat up. I'm told the existing pipework was also flushed out. It's on the ground floor, at the end of the chain and shares a downward drop pipe with another radiator upstairs (also attached to no other radiator except this one). The new radiator heats up well, but when it and the upstairs radiator are both on, only one heats up. If one is turned off, then the other one heats up, even if the thermostat valves of both are set to lower than full on. This never used to happen and both radiators used to work perfectly at the same time. The pipes going into both radiators also appear to be hot, even when one radiator is cold. Baffling! Is there a reason for this and anything I can do to rectify it please, before I go back to the plumbers and complain? Any help or advice greatly appreciated.

 

[JohnD]

Radiators need Balancing.

It sounds like you have (at least) two probiem radiators.

The available hot water will flow along the easiest path, and not through a longer or more difficult path.

To make them all heat up equally, you start by making all the radiators difficult. So you balance, not by opening the cold ones, but by partially closing the hot ones.

Turn off the heating and let it cool down while you work.

Start by identifying your "lockshield" valves. These will be at one end of each radiator, they are the valves that do not have a thermostatic head or a manual knob. They may (should) have a plastic cover to prevent interference.

This may pull off or it may have a retaining screw. Remove the caps from (preferably) all the radiators.

This will expose a spindle. If you have any manual knobs, take one off. There is a good chance that it will fit the lockshield spindles. If not you will have to use a small adjustable spanner or, as a last resort, pliers.

Fully tighten down all the lockshield valves to close them, then open them all by half a turn.

This is because all the adjustment is near the fully closed position.

Then, turn the heating back on and wait half an hour for the water to circulate and temperatures to stabilise.

Then, feel all the radiator pipes. One should be very hot. This is the Flow end. The other will be less hot, or cold. This is the Return end.

Any radiators that are fully hot at both ends, tighten the lockshield by a quarter turn and wait half an hour to stabilise.

All the flow ends should be hot. If not, close down whichever lockshields are hottest by a quarter turn.

Give it half an hour to stabilise.

You may need to fractionally adjust the lockshields, but never more than a quarter turn in half an hour, as the adjustment is very fine and slow to react.

Any that are fully cold at both ends, open the lockshield a fraction.

When water is flowing through all the flow pipes, the radiator will heat up. Identify the ones that heat up fastest, and if any are still cool, tighten the hotter ones.

Your next task is to ensure that all the radiators are getting about the same flow.

The water will cool down as it passes through the radiator, sk feel the pipes at both ends. The Flow should be "too hot to hold" and the Return should be "too hot go hold for long."

You can make further fine adjustment, but if any radiator is too cold, you have to turn down the hottest one(s).

 

[JohnD]

I have edited the post above to complete it.

 

[snaver]

Radiators need Balancing.

It sounds like you have (at least) two pribiem radiators.

The available hot water will flow along the easiest path, and not through a longer or more difficult path.

To make them all heat up equally, you start by making all the radiators difficult. So you balance, not by opening the cold ones, but by partially closing the hot ones.

Turn off the heating and let it cool down while you work.

Start by identifying your "lockshiekd" valves. These will ge at one end of each raduatif, they are the valves that do not have a thermostatic head or a manual knob. They may (should) have a plastic cover to prevent interference.

This may pull off or it may have a retaining screw. Remove the caps from (preferably) all the radiators.

This will expose a spindle. If you have any manual knobs, take one off. There is a good chance that it will fit the lockshield spindles. If not you will have to use a small adjustable spanner or, as a last resort, pliers.

Fully tighten down all the lockshield valves to close them, then open them all by half a turn.

This is because all the adjustment is near the fully closed position.

Then, turn the heating gzcm on and wait half an hour for the water to circulate and temperatures to stabilise.

Then, feel all the raduator pipes. One should be very hot. This is the Flow end. The other will be less hot, or cold. This is the Return end.

Any radiators that are fully hot at both ends, tighten the lockshield by a quarter turn and wait half an hour to stabilise.

All the flow ends should be hot. If not, close down whichever lockshields are hottest by a quarter turn.

Give it half an hour to stabilise.

You may need to fractionally adjust the lockshields, but never more than a quarter turn in half an hour, as the adjustment is very fine and slow to react.

Any that are fully cold at both ends, open the lockshield a fraction.

When water is flowing through all the flow pipes, the radiator will heat up. Identify the ones that heat up fastest, and if any are still cool, tighten the hotter ones.

Your next task is to ensure that all the radiators are getting about the same flow.

Thank you so much for this, JohnD, greatly appreciated. I thought the plumbers had done all this, but obviously not. I'll give it a go and cross everything that I can make it work!