Balance my heating

LostInDharma

Hi,

I had a problem with my heating (blockage) so I drained all the rad's and cleaned out the system.

But Im having trouble balancing the system. My rads upstairs were too hot and downstairs too cold. Now I have it OK but still some rads dont come on properly.

Anyone know the correct way to go about doing this ?

Am I correct to assume the RIGHT hand side is from the bolier and LEFT is to control the radiator on/off temperature control.

Any tips ?

Sparkpea

the ones that arent coming on properly are maybe balanced down too much

no its not always the right side you need to balance, if theres a TRV on the radiator then its the other side u balance, if you have no TRV then you will have a wheel head (on off valve), again its the other side you balance and the wheel head should be open full anti clockwise

LostInDharma

Sparkpea wrote: »

the ones that arent coming on properly are maybe balanced down too much

no its not always the right side you need to balance, if theres a TRV on the radiator then its the other side u balance, if you have no TRV then you will have a wheel head (on off valve), again its the other side you balance and the wheel head should be open full anti clockwise

Hi,

Problem is the white tops are taken off all the rads so I dont know which is the wheel head side. Is there a way to find this out ?

Pete67

Easy way to find out. Leave the heating off for a couple of hours until all radiators are cold. Switch on and check each radiator to see which side the pipe heats up first - that is the one coming from the boiler. Make notes for future reference.

Ideally the lockshield valve (balancing valve) should be on the return side, but in practice it does not matter. Early thermostatic radiator valves were designed to go on the inlet side only, but most newer ones can go on either flow or return. I'd try to get them on the inlet side if possible though.

To balance the system, figure out which side of each radiator is the flow side. This side should have either a handwheel or a TRV on it. Open the handwheel fully, or remove the head from any TRVs installed to fully open the valve. Switch on the heating and set the boiler thermostat to maximum. This should give you a flow temperature of approx 80C. Measure it with a thermometer and note the result. Leave the system on for an hour or so, and measure the return temperatures at each radiator with a suitable thermometer. You are looking for approx 10 degree drop across each radiator when its in steady state, (15 to 20 if you have a condensing boiler) so assuming non-condensing boiler, if the return is greater than 70C close down the lockshield valve slightly, and if its less than 70C open it up slightly.

You may have to repeat several times to get it right for all radiators. Remember to leave a little time for the system to settle down after each flow adjustment before checking temperatures again. For very small radiators in bathrooms etc, it may be difficult to regulate the flow down sufficiently to get a 10C drop, so it it ends up a bit less than that don't sweat it. When done, reinstall heads on the TRVs and set as required to maintain comfortable room temperature.

LostInDharma

Hi Pete67,

Advice worked out great ! I have heat downstairs again

Thanks !!:D:D

Pete67

Glad to help!

Kashkai

I've got 21 rads in my house that badly need to be balanced as some are scalding while others barely heat up. I've read all of the advice above but have a couple of queries:

1. Does it matter what type of thermometre is used, i.e. is there a special type for this job that clamps onto the flow and return pipes or can any thermometre be used?

2. If you get one rad balanced, will subsequent attempts at balancing other rads, throw this first rad back out of balance?

3. Is there one particular rad that should be balanced first, i.e. the closest or the furthest away from the boiler and what way should you work your way around the system, i.e. work away from the boiler or work towards the boiler?

3. I have simple non trv valves on my rads so opening them is clockwise and closing is anti clockwise???

4. Finally, I understand why the boiler temp should be set at max to assist in the balancing process, but following this, will reducing the output of the boiler from its max not also reduce the heat from the rads?

Thanks

Iderown

Prosperous Dave,

Your 2 points number 3.

Go for setting the radiator "closest" to boiler and pump first. Reason is that if they are all fully open at start, then there may be a reduced flow rate to those furthest from the boiler/pump. The flow rate will increase as you do the adjustment along the system.
If you find that you cannot adjust the final radiator(s), then either there is some air in the pipes or the pump speed needs to be increased.

CLockwise = CLose.

Point 4 also. If your domestic hot water cylinder is heated also by the boiler, then the temperature at the TOP of the cylinder will be close to the boiler set temperature. Caution - 80 degrees C can be unpleasant on the hands - even more unpleasant on the naked body in the shower!