bleeding/cleaning pump

[miko]

Hi could anyone tell me if it is possible to clean/bleed the central heating pump. I have a Grundfoss 15-50 pump. It appears to be working (it seems to be making all the right noises) but my downstairs radiators are not heating up. Everywhere else is getting hot, and I was wondering whether there may be sludge in the pump.

 

[bathjobby]

What logic is that ? One radiator is cold so the pump is sludged up ! Where are all the other hot radiators getting their heat from ! (rhetorical).
Fully open the valves on the cold rad see it that heats it up, if not, does the feed pipe to it get hot when you open the air bleed valve ? (assuming water comes out of it and its not full of air). That will prove if you have a flow to the rad, if you do, then the return must be blocked and that can either be in the pipework of the rad itself. Flush the rad and retry.

 

[miko]

The reason I asked about bleeding the pump is that on some forums they say that the cause of the downstairs radiators not getting hot is the pump needs bleeding.

But then again they say the pump may be faulty, and that it may be probable that the pump is jammed. Is it possible to get it going again by loosening the screw in the middle and moving the impeller to get it working?

I do apologise for my ignorance on the subject but it is hard knowing which piece of advice to follow.

I hope someone can help me before my family get hypothermia from the cold spell arrives lol.

 

[Slugbabydotcom]

The reason I asked about bleeding the pump is that on some forums they say that the cause of the downstairs radiators not getting hot is the pump needs bleeding.

But then again they say the pump may be faulty, and that it may be probable that the pump is jammed. Is it possible to get it going again by loosening the screw in the middle and moving the impeller to get it working?

.

Sludge is the most likely culprit. Your pump is having a hard time pumping it round the sytem. Take off downstairs rads and flush them out, while you're at it flush some water out from each rad valve to get the crap out of the pipework as well. Then chemical flush followed by inhibitor. Better still powerflush, but thats more expensive.

 

[miko]

I have tried flushing the radiators, only problem is that all of the radiators downstairs do not turn off from the shutoff valves. They still leak which is causing more problems with the old boiler (My wife not the central heating boiler ) as it is ruining the floors.

I am a complete novice at this sort of thing so is there any way I can completely drain the system or shut it off without causing major problems and how do I flush the system. It seems to me that it would have been easier to take a heating course at college lol.

 

[bathjobby]

We can only help you if you are capable of following the advice given. If your such a novice that you cannot do that, then you need to get a professional in to fix your problem.

 

[miko]

I may have misled you when I said I was a complete novice, I can follow instructions it is just that I havent been given any. I am capable of stripping things down and rebuilding them.

I just havent received information on how to do anything i.e where do drain the system from? and how do I shut the water supply off to the radiators in order to drain the system?. Also when I have shut it off how and where do I flush the system from and what with. I have checked the impeller on the pump and it is turning, but there was a some black sludge in the pump housing when I took the centre screw out.

 

[bathjobby]

Get a professional in to fix your problem. I don't mind advising but can't take it to such a low level that I'm tied up here all day.

 

[miko]

Thank you for your time and trouble bathjobby, but I dont understand what you mean by such a low level. I thought the idea was to advise people who are not fully aware of problems. It must have taken all of 30 seconds to write the reply. sorry to have bothered you..

I must have misunderstood the idea behind the forum I thought it was to help people. Obviously wrong..

If there is anybody on the forum willing to help I would be grateful

 

[bathjobby]

I have tried flushing the radiators, only problem is that all of the radiators downstairs do not turn off from the shutoff valves. They still leak which is causing more problems with the old boiler (My wife not the central heating boiler ) as it is ruining the floors.

I am a complete novice at this sort of thing so is there any way I can completely drain the system or shut it off without causing major problems and how do I flush the system. It seems to me that it would have been easier to take a heating course at college lol.

I can tell you which nut to tighten and by how much (hypothetical situation), but if I have to tell you what a spanner is and how to use it then you are better off getting a professional in and paying for the service.

 

[Gasman1015]

Why not read through previous posts, there is a mine of information here, if you have the inclination. Low level merely means the basics which have been repeated over and over for all types of systems.
If you get stuck on a particular problem then just post regarding that issue.

 

[miko]

Thanks for the comments, I apologise for my sarcastic response its just so frustrating. I am an engineer just not a heating one.

 

[ChrisR]

MIko
Pump would only need bleeding if you'd let air in, but you do it by undoing centre screw.
Pumps can be ineffective due to sludge but cold lower rads are usually caused by sludge in the system not the pump specifically.
If you shut the "good" rads and the "bad" ones all get hot then the problem is just one of balancing.

You can check inside the pump by undoing the four allen screws, and checking the gaps between the vanes are clear. But first you either have to drain the water out or turn off the pump isolating valves. If your PIV's are the type which do not have stems with a nut round(like normal old fashioned tap, without the head) then forget them - they'll leak. If they're DO look like headless taps they can be tried but still may well not work.

To drain system look for a drain cock on a pipe low down, or maybe where poing out through a wall. Stop water going into header tank either with its own tap or by holding ball up.

If rad valves "let by" you can buy caps& washers from a merchant to stop it while you're working with rads off.

If there's nowhere to drain off, takea rad off and connect garden hose to the valve union, (mostly they're the same fitting, 3/4" bsp).

1 min 30. Hope that helps.

 

[Softus]

What logic is that ? One radiator is cold so the pump is sludged up ! Where are all the other hot radiators getting their heat from ! (rhetorical).

The boiler, clearly. You (bathjobby) are one unhelpful MF.

FYI, as you're clearly not a plumber, cold downstairs rads are a classic sign of a jammed, worn, or failed, circulating pump. There are other causes, but there's nothing wrong with miko's tentative diagnosis.

 

[miko]

Thank you to Softus and Chris R for all your help I now have a better idea of how to deal with the problem as I say I am not a complete fool, I just needed to be pointed in the right direction AGAIN THANK YOU