Worcester heatslave 20/25 noisy and over pressurising

bigstuff · 7 Apr 2014

Hi All,

Am new to this site so apologies if my answer is staring me in the face but I can't find it n I need help!
I have bled the system of air,from the rads and the top of the boiler,but when I turn it back on and reset the thermostat reset button again the boiler fires up then the pump starts making an awful noise and gets very hot very quickly but I have no heating or hot water.

It might be significant to say that when I tested the pressure on top of the expansion vessel it expelled black water instead of the expected air. Is this normal or am I looking at the root cause?

Any assistance is greatly appreciated, Richard.

hanns21 · 7 Apr 2014

The fault is staring at you! You have two problems by the sounds of it. Get a gas safe engineer in to have a look at it. Not allow to give advice on boilers. Parts you need are pretty expensive and not a diy job

bigstuff · 7 Apr 2014

hanns21 said:
The fault is staring at you! You have two problems by the sounds of it. Get a gas safe engineer in to have a look at it. Not allow to give advice on boilers. Parts you need are pretty expensive and not a diy job

It's oil not gas!

jeff the gasman · 7 Apr 2014

Your pump is cnaccered try to free it with a screwdriver. Remove the large screw at the front and insert a small screwdriver try to turn the rotor anticlockwise. If it doesn't sort it you need a new pump. That's all.
Good luck.

Armo74 · 7 Apr 2014

Sounds like the system could do with draining down and cleaning as well.

bigstuff · 7 Apr 2014

jeff the gasman said:
Your pump is cnaccered try to free it with a screwdriver. Remove the large screw at the front and insert a small screwdriver try to turn the rotor anticlockwise. If it doesn't sort it you need a new pump. That's all.
Good luck.

Thanks I'll try that first

hanns21 · 7 Apr 2014

Ooo sorry lol your pumps ****ed and new expansion vessel needed,take the cap if front of pump and if its not spinning when turned on its gone. Pretty easy to change tho still expensive as they are a rated pumps these days

Burnerman · 7 Apr 2014

You can renew the pump internals by removing the 4 allen screws......saves faffing with the large couplings. Just replace like for like.
You would have found the 3 bleed points on the top of the boiler, together with the automatic brass one?
John

bigstuff · 7 Apr 2014

Burnerman said:
You can renew the pump internals by removing the 4 allen screws......saves faffing with the large couplings. Just replace like for like.
You would have found the 3 bleed points on the top of the boiler, together with the automatic brass one?
John

Took cap from front and was able to spin pump anti clockwise quite freely.
After turning boiler back on the noise and lack of hot water is still present. Now what do I do?

1983 · 7 Apr 2014

What's the system pressure sitting at on the gauge?

bigstuff · 7 Apr 2014

0.8 bar

oilhead · 7 Apr 2014

If the boiler linit is operating, you could have a diverter valve problem. With all power off, if you try to move the manual lever on the valve, is there resistance? If it is floppy, the valve is stuck in the heating mode, usual cause is the synchron motor jammed. The expansion vessel needs to be replaced.
If the pump is still noisy, it may not be moving any water. If you replace it, do so with a 3 speed grundfos, ( available from most spares stockists as opposed to merchants) if you have a 15-60 model, this can take a 25-60 head. Just change the head, DON'T touch the pump valves or they will p##s out. Replacing with a A rated pump may cause problems with hot water as the pump may decide that it needs to go slower than the heat exchanger needs.

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Worcester heatslave 20/25 noisy and over pressurising

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