Two radiators not heating up after bleeding. Flushing of system required?

[G100]

Hello there all mighty and knowledgeable central heating warriors!

I have two radiators in my duplex flat which fail to heat up. One is a large vertical radiator in the living room, the other is a small ladder style radiator not too far away in a downstairs toilet so both on the same floor. Both radiators not working are very near to other radiators which are fully heating up correctly. I bled all the radiators in the flat and still nothing. I had a plumber call out who tried a number of things but failed to get them working again, he stated that there must be a blockage somewhere in the system and I would probably need a full flushing of the system. He didn't seem at all keen to do the job, almost said he didn't want the job as too much hassle. Said that as my flat isn't on the ground floor, (first floor duplex), it would be a difficult and messy job. I generally didn't really understand much of what he was saying but the bottom line is that my two radiators still don't work and I would love some advice on exactly what you think I should ask of a plumber for this job to be completed successfully and a rough idea of what it might cost. Thanks for any help or advice with this, much appreciated.

 

[milleniumaire]

Hi, I'm not a plumber but I'm in the process of sorting out 3 radiators in my loft that didn't get warm. I tried all the obvious things such as taking the radiators outside and flushing them through and changing the thermostatic valves as the old ones appeared to be stuck, but to my surprise none of this resolved the issue. I assumed there was a blockage, probably sludge as the flow in the loft will have the least pressure and so I tried turning off all radiators to force more pressurised water to a single problem radiator, but again to no avail. In the end I have had to disconnect pipes and force mains water through and this has cleared them. Given the amount of sludge in these pipes I'm considering using Fernox DS40 cleaner, which is a strong acid cleaner and which should reduce limescale and sludge. Based on reviews I have seen I regret not trying this first and suspect this may be something that might help unblock your pipes, if they are indeed blocked with sludge.

 

[G100]

Hi, I'm not a plumber but I'm in the process of sorting out 3 radiators in my loft that didn't get warm. I tried all the obvious things such as taking the radiators outside and flushing them through and changing the thermostatic valves as the old ones appeared to be stuck, but to my surprise none of this resolved the issue. I assumed there was a blockage, probably sludge as the flow in the loft will have the least pressure and so I tried turning off all radiators to force more pressurised water to a single problem radiator, but again to no avail. In the end I have had to disconnect pipes and force mains water through and this has cleared them. Given the amount of sludge in these pipes I'm considering using Fernox DS40 cleaner, which is a strong acid cleaner and which should reduce limescale and sludge. Based on reviews I have seen I regret not trying this first and suspect this may be something that might help unblock your pipes, if they are indeed blocked with sludge.

Hey thanks, really appreciate the response, I'm willing to try anything at this point so will definitely give this a go. thanks again.

 

[Brambles]

Be aware that with any chemical cleaner you need flow, even if it is minimal, for the product to work ( the chemical cleaner has to have repeated contact with the sludge / partial blockage to take it into solution). Once flow is lost, you either need increased pressure, reverse flow or physical removal of the blockage to restore the system.

If a system has only recently blocked, it is probably a small blockage that has built up at a restriction in the pipework - valve / pipe diameter change et al.

Not always too difficult to clean and remove it yourself, but the risk of damaging carpets and decoration et al with filthy water is high.

 

[centralheatking]

If its ferric sludge, go along the radiators and gently knock them with a rubber mallet
and the pipes where you can see them also a really decent strong magnet rolled up and down the rads and along the pipes can certainly break crud up. be carefull not to overload your filter so check it while doing it as you dont want the crud getting into your boiler hex. There is no substitute for preventative maintenance and accurate
inhibitor dosing on a regular basis to avoid massive blocks. centralheatking