Microbore heating problems

[delin]

I have a microbore heating system and the 3 rads to the far end of the house never get hot. I have tried removing all the rads and flushing them clear and checked that they are bled of air but nothing seems to make a difference. Is a power flush now my only option?

Thanks

 

[superdupergasman]

1: Check Trv's are not jammed shut

2: Change pump for nice new shiney Grundfos 15/60

3: Find the manifolds they are supplyed from, drain the system, cut out and clean.

4: Blockage at cold feed/expansion joining point to system?? (Use magnet to check....if it sticks its blocked.)

5: Is the run of microbore too far to supply large rads??

Powerflush will not fix the problem....

 

[delin]

Thanks I will try these with the exception of the pump as it is already a new super powerfull new one! The only problem is finding the manifold for these rads. The 22mm pipe seems to disappear into the wall before it gets to the manifold. I will go on an expedition to find it anyway!

Thanks again

 

[PerryOne]

Under normal conditions on a pressurised system 8mm pipe will deliver 4.5kW and 10mm 7.3kW. Is this enough for your radiator sizes?
The heat loss for these pipes is minimal. But, are they insulated?
I have used them insulated over 53 feet without noticeable heat loss.
First open the air vent, with the pump running, and let the air out, then let the water out until it comes out hot. Close the air vent and see if the radiator heats up.
Question, how long do you run your heating for? Before you decide that the radiators will not heat up.
Was there a time when they did heat up?
What did you or perhaps another member of your family or visitor do to the system?

 

[JohnD]

do they have a valve at each end, or just one valve with two pipes?

do they warm up at all, or is it totally blocked for some of the radiators? It is much easier tyo clean out sludge before it firms a hard blockage.

Do you have a sealed,pressurised system, or is there a feed and expansion tank in the loft?

Is it upstairs rads, or downstairs that are cold?

Can you do basic DIY plumbing?

I see you took the rads off earlier,if you remove them, and open the valves one at a time, does water squirt out? Have you balanced the system, and what happens when you turn off all the hot rads?

 

[delin]

I have been in the house for about 5 years (first 3 years renting it) and 2 of the 3 rads that now don’t work have never worked, the other one used to be warm but not hot. The heating has run permanently for a day with no sign of heat in these rads!
One rad (the one that used to work partially) has a valve with two pipes the others have 2 valves. They are fed from an expansion tank in the loft and the house is a bungalow so are all on one floor.

Yes I have basic plumbing skills.

Thanks

 

[JohnD]

if you can get any flow at all, you can add a chemical sediment remover such as Sentinel X400 which will loosen the black sludge that is likely to be the problem (or one of the problems, if you have several). You can leave it circulating for up to 4 weeks before draining it out with the loosened sludge. If part of the system is totally blocked,and no water circulates through it, then the chemical will not reach the blockage.

You may be able to find a blockage by holding a strong magnet to the copper pipe, it will be attracted to any point where there is a lump of black sludge. If you cannot shift them any other way you may have to cut out the blocked section and graft in a new bit. I am just a householder and do not like microbore.

Black sludge is usually a problem in systems that are old and/or neglected and/or open vented. If you find signs that it is your problem, and can do basic plumbing, a Magnaclean will cost you about £100 and you can fit it on a vertical 22mm return pipe. I promise you will be amazed and delighted to see how much black sludge it traps. You can empty it out and it will continue working indefinitely, and prevent future black accumulations and blockages.

 

[PerryOne]

You need to establish if the pipes are blocked.
Disconnect the hot pipe from each radiator in turn, open the valve and see if water comes out.
If you have 8mm pipes, someone may have kinked one or more, that has enabled a blockage, sometimes emptying the system and letting mains water run through to the dead disconnected radiator will blow the blockage through.