radiator balancing - what to do if you can't turn a radiator down enough?

[Colin Green]

We've had new radiators and a heat pump fitted. It all works, but I'm trying to fine tune the radiator balancing and I'm struggling. There are 4 bedrooms on 1 thermostat upstairs. The thermostat is in the biggest bedroom. I've had to turn the lock shield valve down to 1/8 of one turn in this room to get the coldest room warm, even with its rad valves wide open. The coldest bedroom is still a degree or two colder than the room with the stat. Similarly, one of the other bedrooms is a couple of degrees warmer even with its valves turned down so far the flow is starting to be noisy.

The problem is that if I turn down any more the rad in the room with the thermostat, it doesn't get enough flow to get up to temperature.

It seems to me that the hot room has got a rad that is too big and the cold room has one that is too small. Without replacing the rads, is there something I can do to even them up even more?

 

[DP]

I've had to turn the check valve down to 1/8 of one turn in this room to get the coldest room warm

What does the check valve look like.

Read up how to balance a heating system

 

[Colin Green]

The check valve is a 90° elbow with a brass blade on the top, and a plastic cap that covers it. The blade has 4 turns from fully closed to fully open.

 

[terryplumb]

The check valve is a 90° elbow with a brass blade on the top, and a plastic cap that covers it. The blade has 4 turns from fully closed to fully open.

Show us a picture of this

 

[Colin Green]

 

[terryplumb]

That's a lockshield valve.
They are used to balance the system though. Have you closed down all the radiators that are heating well ,by turning their lockshields clockwise ?
Is it a heat pump ,or just a new pump on the heating system that you have had fitted ?

 

[Colin Green]

We have a heat pump. All the rads and piping are new because the house had microbore when we bought it.

All the lock shield valves are turned to 1/8 of a turn except the coldest bedroom which is completely open.

 

[terryplumb]

Something is amiss then ,you should get the installers back ,they shouldn't have left you with a system that doesn't work.

 

[Colin Green]

Yeah, they went bust. Somebody didn't pay on a big job and they folded.

 

[terryplumb]

Why does it not surprise me that a company who installed what you have ,and doesn't work as it should , have not been paid for other work they did.....and went bust !
You should call in another company to suss out what's wrong,( preferably who have been around for a long time and have a good reputation ) .
Good luck .

 

[Colin Green]

A bit of progress. The other rad on the system is a towel radiator in the bathroom, and it's the rad closest to the heat pump. I'd expected this not to have lock shield valves, but this one does. I turned it down a bit, which has allowed me to adjust the rad in the room that was too hot so that it matches the room with the thermostat. The coldest room is now just under a degree cooler than I'd like, but there's a bit more warmth in its radiator. I reckon I can tweak it a bit more and bring all the rooms to the same temperature.