Best way to find blockage in heating system

shefmarkh

tim_p said:

shefmarkh said:

There is a magnetic filter on one of the pipes to/from the boiler.

Have you opened this up and checked it’s clear of crud?

Yes that has been done and its been cleared.

shefmarkh

So we did have the boiler manufacturers engineer back who replaced the heat exchanger as a precaution, but he confirmed the symptoms are no better. He kindly ran a magnet on some of the pipes where he guessed the blockage might be and it stuck to them. SO was told that is the remaining problem and he is 99% sure once clear this would get everything working (but he can't work on anything except the boiler, so need a plumber).

 Definitely lost confidence in original plumber who said there was nothing to do but randomly cut pipes...so we have a different plumber coming today who hopefully has a good suggestion how to proceed (boiler engineer said probably simplest is to cut out all the blocked pipes and just replace them with new ones, rather than try to clean).

radox2608

M25 said:

How old are the radiators?

A power flush could be the answer but it needs doing properly so get a couple of quotes and maybe a recommendation from someone.

You could also change the first poorly operating radiator for a brand new radiator. Cheap to do but may not give you the results you want (ie the blockage could be in a pipe away from the first radiator).

Also if the plumber could get access to pipes he could use FLIR thermal imaging and that would clearly show a bad blockage immediately.

Lots of options if you're scared of a mess maybe just go with a power flush but if it's a proper job it could take a full day (plumber will leave after setting it up) and may drop into the following morning so you'd have that to contend with.

Also -maybe a plumber could comment- you could have a faulty return or flow valve on one of the radiators. Do you have thermostatic valves?

If all (or most) of the downstairs radiators are not getting warm, this suggests a problem/restriction in either the pipework supplying the downstairs radiators or a problem common to all the downstairs radiators, i.e. debris in the central heating system which usually accumulates in downstairs, rather than upstairs, radiators.

Randomly cutting open pipes doesn't sound sensible. I would try this: Make sure the boiler or central heating pump is running and then close all the radiator valves except one. This would ensure the pump's full force is being used to push water through only one radiator at a time. When you feel this radiator getting hot, open the valve to another radiator and close the valve to the first and so on. Repeat until you have gone around all radiators like this. If all else fails, hiring a thermal imaging camera from somewhere like https://www.stuartdalby.co.uk/thermalimagingcamerahire might help you identify the location of the blockage.

If you do manage to unblock the system, hopefully this will get you through the winter but I would recommend getting the system flushed sooner rather than later. Debris in a system may well cause another blockage unless it is removed.

shefmarkh

radox2608 said:

M25 said:

How old are the radiators?

A power flush could be the answer but it needs doing properly so get a couple of quotes and maybe a recommendation from someone.

You could also change the first poorly operating radiator for a brand new radiator. Cheap to do but may not give you the results you want (ie the blockage could be in a pipe away from the first radiator).

Also if the plumber could get access to pipes he could use FLIR thermal imaging and that would clearly show a bad blockage immediately.

Lots of options if you're scared of a mess maybe just go with a power flush but if it's a proper job it could take a full day (plumber will leave after setting it up) and may drop into the following morning so you'd have that to contend with.

Also -maybe a plumber could comment- you could have a faulty return or flow valve on one of the radiators. Do you have thermostatic valves?

If all (or most) of the downstairs radiators are not getting warm, this suggests a problem/restriction in either the pipework supplying the downstairs radiators or a problem common to all the downstairs radiators, i.e. debris in the central heating system which usually accumulates in downstairs, rather than upstairs, radiators.

Randomly cutting open pipes doesn't sound sensible. I would try this: Make sure the boiler or central heating pump is running and then close all the radiator valves except one. This would ensure the pump's full force is being used to push water through only one radiator at a time. When you feel this radiator getting hot, open the valve to another radiator and close the valve to the first and so on. Repeat until you have gone around all radiators like this. If all else fails, hiring a thermal imaging camera from somewhere like https://www.stuartdalby.co.uk/thermalimagingcamerahire might help you identify the location of the blockage.

If you do manage to unblock the system, hopefully this will get you through the winter but I would recommend getting the system flushed sooner rather than later. Debris in a system may well cause another blockage unless it is removed.

We know where a blockage is now (of course they might be others I suppose), because the boiler engineer ran a magnet on our pipes and it was clearly sticking to one of them for some length. So he recommended a plumber should cut the pipe and clean it out.

Had a different plumber, than the one who recommended random pipe cuts, who said it would be best to put cleaner in the system and run it through. He could also cut that pipe identified by the engineer and have a look whilst the system is drained.

radox2608

shefmarkh said:

We know where a blockage is now (of course they might be others I suppose), because the boiler engineer ran a magnet on our pipes and it was clearly sticking to one of them for some length. So he recommended a plumber should cut the pipe and clean it out.

Had a different plumber, than the one who recommended random pipe cuts, who said it would be best to put cleaner in the system and run it through. He could also cut that pipe identified by the engineer and have a look whilst the system is drained.

Sounds like a good plan. Hope you get it sorted.

lohr500

How handy are you at DIY?
Can you locate any drain valve on the radiator pipework in your downstairs area? Something like this.
Does your central heating have a header tank in the loft?

I hesitate to suggest this, but you may be able to resolve the blockage yourself if you have some reasonable DIY skills.

Happy to provide some tips if you are comfortable taking a DIY approach as I have been there before!

Reed_Richards

shefmarkh said:

...He kindly ran a magnet on some of the pipes where he guessed the blockage might be and it stuck to them. SO was told that is the remaining problem and he is 99% sure once clear this would get everything working 

That's a clever idea which nobody here managed to suggest (and I'm no better than the rest).  Perhaps you need to be posting your questions to a plumbing forum?  

greyteam1959

Running a magnet along the pipes to find a blockage ??
Why not just fire up the central heating and run your hand along the pipe until you find where it is hot then cold ??

chris_n

greyteam1959 said:

Running a magnet along the pipes to find a blockage ??
Why not just fire up the central heating and run your hand along the pipe until you find where it is hot then cold ??

Because the pipe isn't going to heat up at all if there is no flow!

nadsat

Presuming you've done the simple things of bleeding the rads and checking any thermostatic valves aren't stuck, the next thing to do is try balancing the system as this may not be a block especially if it's a large system. Balancing usually involves reducing the lock shield flow on rads that heat up first. There is plenty of how to guides online. I did this helping a plumber who'd put in a new rad for us and two cool rads came back to life.