Help please, again... Central Heating pump!

[blackjoe]

I thought I'd start a new topic as I've made a some developments...

My issue is my Radiators are not heating up and boiler switches off (too hot) prematurely. I worked out it must be a circulation fault.

After removing the motor head from my pump, I found a thick solid residue motor side, restricting the impeller. Cleaned it off and refitted and got the motor to turn by giving it a tap.

Bleed all radiators and managed to individual get to work (had to turn each off in turn).

Just turned the heating on and can hear pump run, but boiler switching of due to over heating.




Could the pump be turning but still knacked?

Been at it all day, yours very pi$$ed off...

Mark

 

[Gasguru]

Take the pump head off an run it...hold the impeller..probably has low torque or seizes up.

 

[spraggo]

Have you turned the pump isolating valves back on and bled the pump?.
If you say you have to tap the pump to get it to start I would suggest you replace it.

 

[blackjoe]

Take the pump head off an run it...hold the impeller..probably has low torque or seizes up.

Thanks Gasguru.

The pump isn't a direct drive, it's an induction type. Myson (circulator SE 125).

Any other thoughts on how I can check the pump?

 

[45yearsagasman]

All of the above may cause your problems.Have you considered that as your pump was blocked then more than likely other parts of your system may well be blocked.Further checking of pipework should be done and it may involve a bit of cutting out.Use a magnet on copper pipe and if it sticks to the pipe then in that spot you have a problem.

 

[blackjoe]

Have you turned the pump isolating valves back on and bled the pump?.
If you say you have to tap the pump to get it to start I would suggest you replace it.

Cheers Spraggo.

isolating valves back on and bleed the pump. I only had to tap the pump once when a put it back together. It now runs but not sure how affective it is

The system doesn't need pressurizing or anything (sorry from car mechanic background) does it?

What is the black solid substance, could that be causing a problem with the outlet of the pump

 

[blackjoe]

All of the above may cause your problems.Have you considered that as your pump was blocked then more than likely other parts of your system may well be blocked.Further checking of pipework should be done and it may involve a bit of cutting out.Use a magnet on copper pipe and if it sticks to the pipe then in that spot you have a problem.

Good point I'll check - also maybe other elements of the pump restricted???

One thing though. All the radiators do work, but only individually I need to switch off all the others to raise the pressure to the single one, or two...

Does the boiler switching off make sense?

 

[blackjoe]

All of the above may cause your problems.Have you considered that as your pump was blocked then more than likely other parts of your system may well be blocked.Further checking of pipework should be done and it may involve a bit of cutting out.Use a magnet on copper pipe and if it sticks to the pipe then in that spot you have a problem.

Okay, I've just removed the motor head again, and used a magnet. Gutted, you're right - above and below pump the magnet stuck and can feel through the outlet this black metallic crud.

The system is obviously flowing but is restricted. What are my options please?

 

[45yearsagasman]

I've found the best way is to cut out pipework that has solid blockages and either clean or replace pipe as required.Chemicals will do the trick on sludge but will take eons to remove solid blockages.Theres not another method other than to get out the pipe cutters and junior hacksaw.

 

[kevplumb]

if its 22 mm pipe try a sparks 20mm spring

 

[blackjoe]

I've found the best way is to cut out pipework that has solid blockages and either clean or replace pipe as required.Chemicals will do the trick on sludge but will take eons to remove solid blockages.Theres not another method other than to get out the pipe cutters and junior hacksaw.

Thanks guys.

Just finished and heating working as should...

I removed the pump fully (instead of just the motor head) and found the inlet 90% block and the outlet 70% block

The pump is cast iron, so I'm not that surprised.

It took 2.5 hours to clean of fully - anyway sorted now and all Fernox'd up...

Thanks again for everyone's help...

Mark