Blocked Microbore to Loft Conversion Radiator

[gasbusters]

Hi,

Another case of I didn't install it but 8mm microbore pipe being blocked.

Combi boiler setup - little or zero maintenance in the last 8 years+ I suspect not even a inhibitor in the system. 9 Rads including a towel radiator - Converted bungalow - Boiler in garage and house on top of garage - So boiler is lowest point.

The highest radiator in the system doesn't get warm hardly. I've had the TRV off (it is checked and working) - at the feed pipe, there is barely a trickle when pump on so assuming that pipe is blocked somewhere - Probably best side of 20mtrs back to the manifold under the main floor in the house and certainly not accessible for the main - Buried in eves, under floors, behind plasterboards etc.

With the TRV off - I've tried draining the system a little then reapplying the pressure a couple of times, also tried a bike pump on the 8mm pipe (again with some pressure removed from the feed side) and still I get a trickle when the system is on. So I know not completely blocked.

I really don't want to have to replace the microbore as much as I'd like too as this would be a huge task given the building works, pipes and location of radiator to the boiler etc.

So looking for recommendations from this forum of excellent members
I am not a plumber by any means ... Give me a Computer Network and I am your man!

My initial thoughts are:
1) Close of the other 8 radiator valves (both sides) leaving the "problematic rad" (PR) open
2) Drain the system fully - assume I need to open the bleed value on PR to allow air in?
3) Install some Sentinel X800 from Screwfix via the PR (see point 1)
4) Repressure the system via the filler loop to 1.5bar
5) Run the heating for 1 hour or so
6) Pray that this works!!!!
7) Let the system cool then drain
8) Install some Sentinel X100 from Screwfix via the PR (see point 1)
9) Repressure system
10) Open the other rads

In other words HELP!!! - The Mrs is complaining that the bedroom is cold

Shut off ALL rad valves around house. Then drain only THAT radiator.

Then slowly....veeeery slowly refil only that rad.

Then only open the valve fully to that radiator, fire up heating, what happens?

 

[uktricky]

Shut off ALL rad valves around house. Then drain only THAT radiator.

Then slowly....veeeery slowly refil only that rad.

Then only open the valve fully to that radiator, fire up heating, what happens?

OK I’ve :
Isolated all the rads
Drained the system
The opened the inlet to the problem rad and then the bleed - little if any air sucking noise!
Then opened the outlet and you guessed it air suck as water drained.
Then closed the outlet and brought pressure back to 2 bar - very little air noise at the radiator but some
Drained again and repeated
Still same
Then opened outlet and filled rad lots of air noise as bleed vented
Closed outlet side and drained - probably a bit more air noise but not lots
Repressured system bleed the rad assume with outlet and fired up boiler
Quickly hit 80deg on heat bulbs and flame cuts I assume as no water to warm will then drop temp a little and flame kicks in - it’s been on whilst I’ve typed this and the feed pipe is hot but return is still cold

 

[uktricky]

So left everything as per above 17 mins later I have a little heat (not hot) in the problematic rad - assume because on the trickle of water getting through rather than residual heat warming the pipe work and the rad - it is minimal and the outlet pipe still cold

 

[gasbusters]

So left everything as per above 17 mins later I have a little heat (not hot) in the problematic rad - assume because on the trickle of water getting through rather than residual heat warming the pipe work and the rad - it is minimal and the outlet pipe still cold

Has it got a thermostatic valve on one end? Is that letting hot water through into rad? If not that valve may be the probpem and need changing

 

[uktricky]

Has it got a thermostatic valve on one end? Is that letting hot water through into rad? If not that valve may be the probpem and need changing

it has (TRV) and yes the rad is warming up a little - Top of rad is now 46deg using a temp gun and outlet area nearer 31deg given the flow rate but this is warmer than it started at

going to leave it whilst I go shopping (and before the Mrs kills me for leaving toolboxes all over the house!) so will see what it’s at when I get home!!

thanks for suggestions to date

 

[gasbusters]

it has (TRV) and yes the rad is warming up a little - Top of rad is now 46deg using a temp gun and outlet area nearer 31deg given the flow rate but this is warmer than it started at

going to leave it whilst I go shopping (and before the Mrs kills me for leaving toolboxes all over the house!) so will see what it’s at when I get home!!

thanks for suggestions to date

If it full heats up, only open the other rads a bit at a time, maybr to turns, see until they heat up, this way you wil force more water to the faulty rad

 

[uktricky]

If it full heats up, only open the other rads a bit at a time, maybr to turns, see until they heat up, this way you wil force more water to the faulty rad

All other rads are fully isolated at present - There is as much as there can be I believe going to the faulty one which is still lukewarm or 46deg on the top!

So million $ question now ... assuming I've not got a crushed pipe somewhere (cannot think I would have given no other works in the house) is it worth trying some x800 cleaner? Any special tricks when using this? given my flow is so weak to that rad? I've read about leaving it in for about an hour somewhere - at an hour I doubt mine will have cycled the once!!!

Which also opens the question of how do I get it into my system - I'd assume through the towel rail as that has an opening on top but obviously that is also isolated at present!

 

[jackthom]

If you have at least some flow through the problem radiator it would be worth trying to run some cleaner through the system with only that radiators valves open IMO.

If you can easily get the cleaner into the towel rail it's OK to leave both of it's valves open long enough to get the stuff evenly distributed around the system (maybe 10 minutes to be absolutely sure) then close off the towel rail valve again.

Keep all other radiators closed until there is a real improvement in the flow through the blocked pipework.

 

[gasbusters]

X800 is a very aggressive cleaner, your more likely to cause further blockages. I would advise to take that one radiator off, then when its off, open the valves one at a time on either side to see the flow/pressure. This way you can be sure if its the rad, or valves.

Also you can flush out the radiator in the garden by using either a pressure washer, or a hose pipe. If you font gave neither, pop down to your local romanuan car wash and ask them to blast tjrough the radiator with their pressure washers (ive had yo do this in past when working far from home)

But based on what your saying, in my exoerience, 90% of the time its the thermostatic valve thats needed changing

 

[uktricky]

X800 is a very aggressive cleaner, your more likely to cause further blockages. I would advise to take that one radiator off, then when its off, open the valves one at a time on either side to see the flow/pressure. This way you can be sure if its the rad, or valves.

Also you can flush out the radiator in the garden by using either a pressure washer, or a hose pipe. If you font gave neither, pop down to your local romanuan car wash and ask them to blast tjrough the radiator with their pressure washers (ive had yo do this in past when working far from home)

But based on what your saying, in my exoerience, 90% of the time its the thermostatic valve thats needed changing

With the TRV the flow isn't great so we've ruled that out I think

Well I've ordered some X800, filling kit (To limit the spread of the stuff!), and a Magnetic thingy for the return path
Collection on Tuesday
Will install the Magnetic thing first then try 50% of the X800 with a single rad for a bit
Wish me luck!

 

[terryplumb]

Change the TRV. Before anything else.

 

[ianmcd]

be very carefull using X800, if you dont get it all out you will damage your pump and possibly pin hole some other rads it is very very aggresive

 

[uktricky]

Right ... an update !!

installed a magnetic thingy on the return
The pipe (22mm) when I had it open was filthy inside black soot like substance on my finger after inserting
Filled and drained whole system twice
Had TRV off again - definitely works and is definitely open
Attached bike pump to inlet side again and it almost holds 1.5-2 bar of pressure - daren’t go any higher!!
Did this a few times and still same
Tried to push something down the pipe - got passed first 90 deg bend and probably about 8” behind partition wall but assuming blockage is there or another 90 deg bend and I cannot get past there with the wire I’ve used - tried using a net curtain wire but that doesn’t get passed the first 90 deg
So using the bathroom towel radiator I’ve put 50% of my x800 in and filled the towel rad and problem rad
All others are isolated and the heating has been on 25mins!
I hope this stuff works otherwise I’m going to be repiping this - least I can install another rad if I do at the same time!

how flexible is this 15mm barrier pipe (assuming that is what I need between the 22mm and the rad)

will advise what happens in about an hour when I drain the system again!! Hoping for miracles but not expecting a result

 

[John D v2.0]

Can you tap into the offending pipe at the boiler end too and connect a long hose pipe to the radiator end to force whatever it is back into the other end? If you can blast it backwards into a bucket you'd be in a better place.
Also don't go pumping up the pipe with air as that stores a huge amount of energy, always use water pressure instead.

 

[uktricky]

So after 1:15 of x800 pumping around - I drained the black stuff quite literally- this system has never been cleaned I am guessing or had inhibitor installed.

flushed it a few times and gave up - I’ve opened all the rads bled them and stuck some x100 in for good measure.

Re-pope looks to be the solution but I know I need to run some cleaner through the other rads having seen the colour of the water that came out!!!

Thanks for everyone’s suggestions on this thread but fair to say this blockage is going nowhere! The only other thing is possibly a crushed pipe??? There is probably one area that might happen so will check as this area needs to come up for new pipes anyway!!

total respect for you plumbers - it’s a cruel job when you cannot see the problem! Give me a data network any day!!!