Central heating nightmare!

[terryplumb]

He can't find FAQs
It at the top of the forum page in this section.

If he cant find the FAQ 's ,he is gonna really struggle with finding dead mouse remnants

 

[FiremanT]

It would appear that your blockage has just happened.


Pete

Almost certainly wrong. The blockage is likely to have developed aver an age. It only comes to light when the system is drained, or water leaks or evaporates until the water drops below a critical level.

It is possible for a competent DIYer to sort out, but the posts to date imply, to me, that this is a little out of the OPs range.

 

[terryplumb]

As FiremanT said ,the blockage has not just occurred ,but is historic and only became apparent after op drained down and fitted a new rad. If the op has ammended pipework to fit a new rad then i see no reason why he cant cut out and replace any blocked pipe / fitting. He may well have difficulty finding the blockage !!

 

[lostinthelight]

It may be possible to cut the 15mm pipe from the tank at or near to where it joins with the larger bore pipe and if the blockage isnt there, back flush the pipe back into the tank?

 

[Jethro Tull]

Dont connect mains water. Pump running is a separate issue and can be looked at later. Firstly Sort out the blockage ,which will be somewhere on the pipework from the bottom of the f&e tank which feeds water into c/ heating system / boiler. If you have a strong magnet ,run it along the copper pipe ,it will be attracted by the blockage in the pipe which is invariably magnetite. Usually found near the first "T" on the pipework ,but not exclusively there. Isolate the electric supply to the boiler to stop pump from running ,if you havent already done so.

You were right. The feed from the tank was totally blocked at the T. I cleared it and bled the system. But the nightmare continues. The mains water pipe to the stopcock is also blocked. It's an old iron pipe and someone has fitted copper sections at both ends. Anyway, now the boiler fires up for a few seconds and stops. The pipes are really hot and so is the pump even though the boiler isn't running for long. There is still no water or air comingh out of the pump screw. There is feed to the rads because they bleed OK and the tank level goes down now. The boiler shows no fault in that the green light is flashing (potteron Suprima 30l - 100l). I think I ma going to have to call a heating engineer and maybe replace the whole sad system. We moved into this place a few weeks back and didn't realise the CH system was so rubbish. Thanks for your help (including everyone who has commented).

 

[terryplumb]

Stopcock blocked ? Please expand on that. You probably have not got all the blockage out from the pipework ,how did you go about it ? All other syptoms ,pump dry ,boiler cuts out etc is all down to no circulation / lack of water.

 

[Jethro Tull]

Stopcock blocked ? Please expand on that. You probably have not got all the blockage out from the pipework ,how did you go about it ? All other syptoms ,pump dry ,boiler cuts out etc is all down to no circulation / lack of water.

I cut the 22mm feed pipe in two places, cleared the hard deposits at the T and connected it all back up. Yes I am sure there are blockages in the system still but it was working OK until I drained it down the first time to fit the new rad. Maybe it released a lot more deposits and has gummed up the heat exchanger. So I cleared the tank feed problem and now I appear to have another blockage. The mains must be a problem on its own so I need to cut out the iron pipe and install a copper feed. I am draining the sytem down and am going to try a cleaner like Sentinel or Fernox and see how that goes first. Thing is, the hose attached to the drain has stopped running but there's still water in some of the rads as when I open the bleed screw water comes out under pressure.

 

[terryplumb]

Chemical cleaner wont do much if you cant get circulation. This stopcock ,can you post a pic of it ? What is it isolating exactly ? What and where is the drain hose connected to ? Can you post pics of the pipework you worked on and the pump position in relation to it ?

 

[Jethro Tull]

Chemical cleaner wont do much if you cant get circulation. This stopcock ,can you post a pic of it ? What is it isolating exactly ? What and where is the drain hose connected to ? Can you post pics of the pipework you worked on and the pump position in relation to it ?

Sorry I should have said ball cock on the feed tank. I disconnected a joint further down the pipe and there's hardly any water comming out and obviously it should be high pressure. The pipe divides into the cold water system as it comes into the house and there's a stop cock in near the junctionjust before the split. The cold water comes through well so it must be the feed pipe to the tank that's blocked. I connected the drain hose to a rad near the door and opened the valve.

Almost certainly wrong. The blockage is likely to have developed aver an age. It only comes to light when the system is drained, or water leaks or evaporates until the water drops below a critical level.

It is possible for a competent DIYer to sort out, but the posts to date imply, to me, that this is a little out of the OPs range.

I am a competent DIYer. I have installed a whole central heating system from scratch and built three extensions. I just don't know much about CH faults.

 

[terryplumb]

It would be very unusual for a mains cold water pipe to be blocked. Is the " stopcock " a wheel head ,gate valve ?They are total krap.
Draining down the system as you describe would empty pipes and rads above ,but not necessarily those on the same floor .

 

[Jethro Tull]

It would be very unusual for a mains cold water pipe to be blocked. Is the " stopcock " a wheel head ,gate valve ?They are total krap.
Draining down the system as you describe would empty pipes and rads above ,but not necessarily those on the same floor .

Yes it did seem rather odd but I managed to sort that part out. The property is a bungalow btw. The roofspace was a real mess of pipes and insulation. As the house was vacant for 2 years it would seem that someone turned off a second gate valve on the mains feed for some reason, which was buried in the insulation, maybe in case it froze up. So that part is now solved.

I am getting a heating engineer round to trace the other blockage or air lock next week. Cheers.

 

[SpecialK]

Pull the pump out and clean the impeller its probably blocked... also get some form of “magnaclean” as your system is probably full of bits!

 

[Jethro Tull]

Pull the pump out and clean the impeller its probably blocked... also get some form of “magnaclean” as your system is probably full of bits!

Yes I did that last night and the impeller is free with no residue. I did consider a flush but it won't fully drain so I think there is an air lock somewhere or the fact that I freed up the system by unblocking it, it could have caused another blockage. So I don't think I will be able to flush it properly anyway.

 

[ianmcd]

As already advised you will need to get everything circulating before you can use chemicals to flush it, the chemicals dont clear blockages

 

[SpecialK]

Did the pump run ok when out? Did you have to drain a lot of water when you removed the pump? Can you open the gate valves a bit too see if water is there?
Did you shove something all the way down the flutes of the impeller to make sure its completely free?
I your 3 way valve in the right position?

Yes I did that last night and the impeller is free with no residue. I did consider a flush but it won't fully drain so I think there is an air lock somewhere or the fact that I freed up the system by unblocking it, it could have caused another blockage. So I don't think I will be able to flush it properly anyway.