Help please. 2 cold upstairs radiators

Careful_ly

I'm not sure this is something we are going to be able to fix but here goes.
Two upstairs radiators not working the feed pipe to the rads is hot, both radiators have thermostats, one on inlet the other on outlet side.
We have removed the tops from thermostats and the pin will push down and springs back up. We have removed dust cover from other side of radiator and turned the balancing thing. we didnt know which way to turn so have tried from fully up to fully down. dont now know where it was to start with!! Have also tried gently tapping the thermostat. Have also tried turning off all other rads, leaving just these 2 on.
Anything else you can suggest other than flushing which we dont feel able to try. House is 60's has been extended and the 2 rads in question look very new, floor standing boiller downstairs in garage (gas)

ceebee_2

It might be stating the obvious, but have you tried 'bleeding' the radiators?

This should be done with the pump switched off.

Careful_ly

Yes Ceebee we have bled the radiators. We did it with the system on though, would that make alot of difference?

alanobrien

This sounds very very odd.
If the valves are open and you shut off the other rads and bled the system you should get some heat unless either ;

The TRV's are stuck closed internally - possible but to happen on 2 rads is more of a co incidence than i would believe.

The Rads are completely sludged - again possible but if you bleed it and are seeing water flow then they are not completely sludged.

The inlet pipework is blocked - again possible but you say they get hot so unlikely.

Not sure if yours is a pressurised system or not but i would be inclined to close of all the other rads. Set your balancing valve to mid point on the dodgy rads so you know its definately open.

Then increase the system pressure a little at the boiler bleed the rads again and run the system.

I would even do the above on 1 dodgy rad at a time to focus the water flow.

Other than that i guess you will need to get someone in to look at them.

Mr_Warren_2

Bleeding radiators has to be done with the system "stopped". If you attempt to bleed radiators whilst the Central Heating pump is running, you will suck air in (and not out). If you have a Combi boiler, check the pressure gauge on the boiler. This should be on or just above 1 bar when system is cold. If the pressure drops when you have (or are bleeding) the rads, you need to re-pressurise your system by injecting water in by opening a valve somewhere around the boiler (only you and your service men would know where that is) in order to finish the bleeding operstion.

I hope this helps.

bruce2110

i have been thinking about this problem and i think you may have 'crossed pipes'.

if you say this is a new build property, and you are getting heat at the valves but not across the radiators, plus the fact you say two are doing the same, then i think the pipes must be crossed under the floor - eg two flow pipes to one rad and two return pipes from the other rad.

you will need to contact your builder and ask them to get the installing company to return and rectify this problem, i work on maintenence in new build propertys and this type of problem is not that uncommen and can be rectified quite easily a compitent plumber....

it usally tkes a couple of hours from start to finish on the type of systems we install so it shoudnt take up too much of your time!

hope this helps!!

Careful_ly

Have just come back from my daughters, where radiators are have tried everything suggested and still wont work. The house isnt a new build bruce, my daughter moved in last Friday it is a 60s house which has been extended to the rear a couple of years ago. Before completion the lady of the house let my daughter know the 2 rads werent working, but said her plumber was ill and couldnt come before the move. Of course we dont know if the 2 rads actually have ever worked.... could be crossed pipes?
The 2 rads look very new they have the blade things between the two panels, the master bedroom one actually was hot after the thermostat which is on the inlet on a sort of ball shaped thing at the bottom, but rad didnt heat up.We think not a diy job anyone know a plumber in Bramhall, Stockport?

Ps. is not a combi system

bruce2110

do you know what size the pipe work feeding them is? - eg is plastic pipes feed from the back off the rads or is it copper pipes from below (from the floor)

Careful_ly

Its normal size not microbore. Copper pipework 15mm????

Yes from below

bruce2110

ok. as alanobrien said earlier, i think the route cause maybe down to balancing the radiators, this would the most obvious cause as you say this is in an exstension etc

1st point is to ask your daughter what speed her pump in the airing cupboard is set on it should be set on number 2 (small adjustment on side off pump may need a tourch to see it properly)

2nd point are the rest off the rads in the house getting hot ok? - is there any of the rads that seem to be hotter than the others(not including the two problem rads)

3rd point balancing rads - the method i use seems to work for me but i'm sure that many others use different methods but here goes....

tools required - hand grips(pupmp pliers/wrench/adj spanner) if the lock shield side is screwed then posidrive (phillips) screw driver to help remove white cap

firstly as previously suggested, i would close off all your rads at both ends - one end with the trv and the end with the small white cap on (lockshield valve). leave only the two rads you are having trouble with on, fully open trv and the lockshield side, then turn the heating on full. after about ten mins check the two rads too see if they are hot if they are good!! if not then it would be definate indication that the pipes are crossed.

however, if they do get at least luke warm, then it could be an indication that the pump could not be working properly. - if so, pupmp change required

if rads get nice and hot after 10 - 15 mins then all you need to do is balance the system which will take about an hour or so - to do this, leave the system on then from the nearest rad to airing cupboard, open up each rad in turn, lock shield side first - first rad about half a turn of small spindle, then open up trv or wheel head valve to 3 or three turns(roughly half)

as you go round, open each valve up half a turn more untill all valves on top floor are opened and all trvs or wheel head valves are set to number 3.

go down stairs and do the same here except all rads down stairs shold be opened three full turns on the lockshield side with all trvs/wheel head valves set to three

see how this goes, if all the rads start to get nice and hot then thats good, check the two problem rads and if they remain hot then good but if not, then you could adjust the lockshield side on the down stairs rads by reducing the lockshield side down by one full turn

if all this still fails to help, then i recommend you engage the services of a local plumber - if you re-post on here you may be able to find or have someone recommend a local plumber to your area

good luck!!...

Careful_ly

Thank you Bruce for your very detailed reply.
I know the pump is set at the highest speed as I checked it today, It is actually sited next to the boiler which is a floor standing one in the garage. All the radiators apart from the faulty 2 are lovely and hot.
I am a little afraid to try what you describe as my daughter will kill me if I mess up the other radiators.