Stubborn blockage not cleared after two powerflushes, what next?

[mhnp]

Is it a one pipe system? I.e there is one pipe under the floor and both sides of rad are connected to the same tube?

No there are separate supply and return pipes running parallel

 

[mhnp]

Hello mhnp I used to live in Bracknell a while ago so understand what problems you can get , sound's like the people who did the flushing don't understand how to do it the correct way, if you have micro-bore pipe (10mm) its not recommended to power flush, if you have the time and some one to help you , drain system remove the problem radiators take them outside turn upside down and connect a hose pipe to flush through at the same time bang along radiator with rubber mallet, check radiator valves, replace if necessary, refill system and add Fernox F5 heavy duty cleaner try to add this into a radiator or towel rail (direct into system) run system for 1 week drain, Refill using Fernox F1 inhibitor. worst case you may need to replace some pipe. Any problems I am sending you someone's number in Wokingham.

Thanks for the contact. One thing established with some certainty is that there is not a coincidental blockage in each radiator so I am not clear what manually flushing each rad would achieve.

 

[gassafe]

Powerflushing is not designed to clear a blockage! If the pipe is blocked then the powerflush won't get any circulation through it. They don't operate at 2 or 3 bar either!

Disconnect a rad and get a foot pump on the f & r tails. That will show up a blockage!

 

[Ermintrude]

Just read above post again..... Nothing like duplicating !

Ok may or may not help, cut flow and return after last working rad, attach either a test gauge so u can use a compressor or just attach hose (2 jubilee clips) other end secure a full bore ISo valve and then hose to outside. Close ISo and blow system up to 3 Bar or as high as u dare. Once full crack ISo fully open and hopefully obstruction is removed. Doubt it's going to be a 10mm stop end or cement plug probably large bits of rust dislodged by your power rusher!

 

[mhnp]

Powerflushing is not designed to clear a blockage! If the pipe is blocked then the powerflush won't get any circulation through it. They don't operate at 2 or 3 bar either!

Disconnect a rad and get a foot pump on the f & r tails. That will show up a blockage!

Was wondering about pumping with air and how to get an airtight connection. is this the sort of kit I would need?

https://www.NoLinkingToThis/p/monument-dry-pressure-test-kit/72940

 

[heliotrope]

Pumped heating and hot water

Not very likely to have a check valve in the system then.
Can cross that one off as a blockage point.

 

[mhnp]

Just read above post again..... Nothing like duplicating !

Ok may or may not help, cut flow and return after last working rad, attach either a test gauge so u can use a compressor or just attach hose (2 jubilee clips) other end secure a full bore ISo valve and then hose to outside. Close ISo and blow system up to 3 Bar or as high as u dare. Once full crack ISo fully open and hopefully obstruction is removed. Doubt it's going to be a 10mm stop end or cement plug probably large bits of rust dislodged by your power rusher!

Similar idea. Any reason to cut pipes rather than remove a rad valve? Also would it not be better to go from a non working radiator as the blocked section would be much easier to pressurise.

For an air compression approach, should I drain system first?

 

[Ermintrude]

Yes drain down. Close off rads as blockage isn't in rads, leave furthest rad fully open when blasting out system. Close furthest rad when draining down, and then open once pressurising set up is connected so that water from rad will go through pipes hopefully moving debris with the compressed air.

Make sure drain down pipe is secured with jubilee clips on to other side of ISo valve.

To pressurise i use a monument dry pressure test kit.

Cut F&R as that's where blockage is and if you just blast it down rad tee, the poop will go into rest of system.

When u cut pipes put towels and paint roller tray on ceiling between floor joists as there will be water in pipes.