Plumber can't balance central heating

[munchkinmaster]

We had a new combi system put in as part of a bigger refurb. Not really used the heating till now but have had plumber round 3 times as some of the radiators are always cold. He'll get the ones I complain about hot but then others will be cold. Is he just being crap or is there a bigger problem?

[gamerchick]

I had the same when I got a new heating system. The dude told me I had to choose whether to heat the upstairs or downstairs

Its better now 8 years on but still shit. I crank the thermostat right up for an hour on the boiler and bring it back to 6 oclock

[PigletJohn]

try it yourself.

Before you start, get a notebook and note down, for every radiator, how many turns it took to screw the lockshield fully shut, so you can put it back where you started.

If you haven't got a knob that fits the lockshield, you can buy a spare knob with adjusters to fit numerous spindle sizes. Or you can use a 4-inch adjustable wrench, but it will wear the soft brass spindles over time. Or one of these may fit. Don't use anything that is a loose fit or you will round off the spindle.

Try this:

www.mumsnet.com/Talk/property/a2205419-New-radiators-not-getting-hot#50023831

Remember, you don't do it by opening the cold ones further. You do it by closing the hot ones more. Once there is warmth in all the radiators, don't turn any lockshield more than half a turn, then leave it running for half an hour before you turn it again.

If you have added extra radiators added to existing pipes, for example in an extension, it may have been done so that some of them will never have enough flow. TRVs may help a bit.

[munchkinmaster]

Thanks. I know I should just diy but hard with two small kids and the problem radiators are in their rooms. It's a whole new system so should work perfectly.

He also says I won't get fast heat up if underfloor on at same time. I can see why. I've set this to go on and off twice a day. Do you think I should put it on really low on constant or alter the times so not same as heating. Underfloor is in a rarely used room but the room connects via a stairway (no doors) to rooms we do use so don't want it sucking heat out.

[PigletJohn]

If the kids rooms radiators are the cold ones, you don't need to touch them yet.

If you use UFH, it is usual to set the timer so that it turns on an hour or two at least before your radiators. You will find out in your house how long it takes for the heat to come through. In a concrete floor it can be a long time.

If you have some radiators that are cold and some that are hot, you can make a start by feeling the pipes under the hot radiators. The pipe at one end will get hot quicker when you put the heating on. This is the Flow pipe. The pipe at the other end is the Return pipe and should always be noticeably less hot. Write "F" and "R" on the pipes with a narrow marker pen, so it is not noticeable but you will be able to see it when you look. Next time you have ten minutes, feel the Return pipes on the hot radiators. Decide which of them is hottest. That is the one you should turn down first. If you are short of time, just do that one, and next day, feel it again to see if the Return is noticeably less hot than the Flow. If not, turn it down again. Once it is noticeably less hot, walk round and feel the other radiators, to find the one that now has the hottest Return, and turn that down. This will cause more heat to flow to the other radiators.

If you haven't got time to do them all in one day, at least do one. Once you have found how easy it is, you might do more. Remember only to turn them down a bit each time. The correct setting will be probably somewhere between half a turn and two turns from fully shut, which is surprisingly little. You only adjust the Lockshield valve, which is the one that (normally) has no knob on it, just a cover. The other end should be fully open.

Consider getting a door on that unused room. Heating an unused room is money down the drain.