Boiler noise

[mackredie]

Hi can someone help we've got an old Halstead Boiler which fires and runs and hot water gets quickly to the pump which appears to be working (screwdriver test) runs freely. It then slows and stops circulating with lots of banging and bumping and then the thermostat shuts off the boiler. We descaled the system last year inlcluding taking out and descaling the heat exchanger. Everything worked fine.

In September we switched on and it worked fine for two or three days then this problem began. The system has been drained and refilled half a dozen times so there is now no longer any fernox in the system but the water runs clear.

Does anyone have any ideas, has the pump had it?

Thanks in advance Mackredie

 

[Agile]

I once found a pump which went open circuit when it got hot!

Tony

 

[mackredie]

Thanks Tony could well be, how did you establish that and I take it the pump needed replacement.

regards Mackredie

 

[2face]

i would go for the pump .. halsteads were not the best of build boiler. good luck .

 

[fitz1]

impellors may be broke in pump.

 

[mackredie]

2face Thanks for your replies Halstead been very good for thirteen years. Many repairs later there is still nothing wrong with the boiler!

fitz1 impellers may well be 'broken' water pumps have very little to do with gas

Sorted

 

[Prof.plumb]

I would say there is a strong chance the pump is knackered the banging and the stat cutting the boiler off is caused by the latent heat at the boiler end i.e the pump is not circulating the heat away from the boiler quick enough hence it bangs, overheats, cuts off. Change the pump.