Help needed after a power flush please

thechippy

As stated earlier, the boiler is switching off due to a lack of water flow, so it's reaching it's setpoint temperature prematurely.

Causes;
Faulty pump (but that's been replaced)
Pump installed the wrong way around
Faulty zone valve (doubtful, as they divert the water as required for heating or hot water, but should not stop the flow entirely UNLESS it's clogged)
Full or partial blockage in the flow or return.

I think others may agree, but I'm not convinced of the guys skills. He said the pump was noisy because of air - if so, why didn't he do something about it? The pump should be virtually silent!

Sorry, I know you've been happy with him so far, but I'd get someone else in....;)

albyota

Warning I am not a Gas safe Engineer, but.... my thought are that if the boiler fires up, and then shuts down after a short while, and as above the obvious things have been looked at and dismissed, then it could be that the fan in the boiler is failing. from cold the fan will run, but after a short time the heat from the boiler expands the fan spindle and if after 15 years the bearings are likely to be dry, the fan will slow down and stop. with no airflow from the fan to get rid off the fumes the airflow switch will go open contact and shut off the gas valve....And/or....... the high temperature stat which is fitted between the flow and return pipes should be fitted onto the flow only...this was a fix from baxi.

by the way the pump is designed to over run for about 6 minutes

Actually... i'm not sure if there is a fan fitted in this boiler.....ho..hum..!
someone will soon shout at me,:eek:

needmorefreebies

there is a fan in the boiler and it was rpelaced a couple of years ago. I ddint have any of these problems before the flush. My only problem was that the radiatiors were not getting hot all the way down to the bottom and a couple of radiators were not working.

The plumber said the air was in the radiators and not the pump and it would take a couple of days to settle down???

albyota

Has he or even you gone to every single radiator and bled the air out of each one? and again recently, are all the valves open on both sides of the rads?

needmorefreebies

yes i have bled all the radiators and they were fine. He is coming around tomorrow lunchtime so hopefully it can be sorted then and as far as I know the valves were cheked on both sides of rads before they left after the flush. Will let you know

needmorefreebies

I have bled all the radiators and they are fine, as for the valves Ibeleive they were all checked and open after the power fluxh, i personally havent checked them. Plumber is coming back tomorrow lunchtime so fingers crossed he can work it out, thanks

thechippy

Good luck tomorrow.

No matter how many times I read this, I keep coming back to a blockage or restriction in the system.
Why did he remove the kitchen rad when he flushed?
Did he use a flushing agent that assists in removing the crud?
How long was it flushed for?
I realise it's been flushed, but if not done properly, a restriction / sludge could still remain.

Sorry, but I'm still dubious of his skills. Comments like "pump is noisy due to air", but he does nothing about it?
"air in the system, but it will settle down" - rubbish! Do something about it!

Give him a last chance - fine, and I respect you for that, but if it's not sorted tomorrow, get someone else in........;)

Good luck

albyota

Yep..... I tend to agree with thechippy on this, although a lot of the details are unclear, and it could still be a number of things we have already discussed.

thechippy

Update please.........:p..;)

needmorefreebies

Apologies for delay in getting back to you all, working late last night.

Yes there was a blockage & I will try to explain where is was for you. The pipe that runs up from the boiler is bridged by a pipe that goes into the pump and the blockage was in there. Not sure if a power flush would have ever have reached that point, maybe you would know better?

Anyway the blockage was cleared, the pump is now quiet and I have a lovely warm house.

Many thanks for all your suggestions I am very grateful, especially Alan for your advice on the phone and it seems that the little honeywell box is fine.

Sue