Central heating problem

[The Plumber Guy]

Hi fellow plumbers and a happy new year to you.

I'm getting to the end of a problem with microbore central heating where very few radiators actually worked. Having taken them off the wall and flushed them through with a hose - and opened the valves to let any sludge out - 3 of the radiators out of 18 are still not working properly. I was wondering if any of you have had similar problems with microbore and if you can suggest a solution.

Many thanks - Guy

 

[PlumbBobBob]

hi have you tried closing the ones that are working to force water through the non working ones?

 

[FD Powerflow]

as Steve says below, the problem lies in that microbore can block so easily that in some cases even powerflushing with a very strong cleaner wont shift anything. Sometimes its a case of repiping im afraid.

Check if there's any flow to the rads in question by shutting off all others on the system, if there is then you would benefit from a powerflush / filter and cleaner being ran through the system.

The powerflush will force sludge out of the pipework which is what taking the rads out cant do. The less aggressive way to clean is simply to cut a section of pipework somewhere on the return and fit either a Magnaclean or a TF1 and introduce a cleaner such as F3 and leave to circulate. Run the boiler at max temperature with all poor circulation rads open and others shut, check the filter every couple of hours or so over the period of a day and see how you get on.

Best of luck

 

[The Plumber Guy]

Thanks very much for those answers. I don't know if you guys will get this automatically but with the rads that aren't working, the feed pipes and the TRVs actually going into the radiator are both too hot to touch and yet the hot water doesn't go any further and start the convection process inside the rads. Does this make sense to anyone? Cheers.

 

[Bartdude]

Maybe the TRVs are stuck?

 

[The Plumber Guy]

Not to my knowledge Bartdude - the pins are all up and the heat extends past the vertical part of the valve and into the radiator so I'm stumped. Very jealous that you are in Devon by the way!

 

[mikeygas]

Sounds like airlocks and or balancing issue's. Run heating but turn off all the rads except for the three that aren't working. See if any of these three rads then get hot. If not close off all the rads except for one of them to try to force the system heat through, once this rad is hot do the same for the other two.