Boiler Mate 111 Pump Problem

Hi

I have a boiler Mate 111 that is 12 years old and is great when it works.

In recent days the pump that serves the boiler stopped working. It was seized and would not spin at all and was getting very hot.

So I bought a new Gundfoss pump and had a plumber friend fit it for me. The isolator valves above and below the pump were rotten and needed replacing.

( The plumber friend does not hold this system in high regard ).

So with the new pump fitted the system worked for half an hour and then stopped ( i got one tank of hot water ). The new pump would not pump!

The new pump is free to spin ( checked ) . When switched on it sounds like some pressure is being exerted but no flow and the pump is not spinning. The boiler fires up correctly but quickly shuts down as it overheats. The pump is not getting hot. The plumber freind suggested their may be an air lock so I drained the system again and refilled again. This had no effect at all.

So today I have cleaned the old Grundfoss pump and refitted it ( it spins freely now) Once fitted it behaves exactly the same as the new pump ( I read somewhere someone saying about various voltages, so I thought maybe the old one has some special voltage or something).

I am now thinking that maybe I need my 4th circuit board ! Or could there be a blockage somewhere ! Would a blockage of the Y filter thingy cause the pump not to spin? If so to clean the Y filter do I have to drain the system again ?Is there a pressure sensor which cuts out the pump if there is a blockage?

Gledhill quote a no fix no fee service , does anyone know how much this is ? Will they replace the curcuit board ( which costs lots , you can get a good pc for the same money as a curcuit board ).

The curcuit board says -on and the bottom two led's are green

Any ideas or suggestions (before I take a hammer to this system)?

Get the big hammer out.
Or study the the book a bit more.
The Y type strainer valve has no bearing at all.
I suppose a call to Gledhill would answer those questions.
When the draining was carried out, where from?
The unit
The boiler
The system?
Are the pipes from the boiler to the unit clear? As in not sludged up?
The biggest reason why these units fail are;
The guy who fit them when all shiny and brand new and the later ones too.
Never put any or enough inhibitor in them!
If a plumber don't like them it is because he can not mend it!
And would much rather fit what he likes. Not always what's good for you the customer.
Have you the book / manual.
If not down load one for free from GLEDHILL.
Other places on the net will do their best to charge you.
Have you read the section with ref to your unit and the posts.
Mike
MGCH2O
Norfolk

Just to add.
Why not try running it with the pump head off?
If there is a supply to the pump which will be when the boiler is firing?
Is there a pump over run on your boiler?
If so trouble could be elsewhere!
Nothing is easy, but with some thought etc.
Mike

Hi Mike

The first draining was from a drain just above the boiler ( done by plumber freind)

The second draining was carried out by me today , upstairs was drained from above the boiler and downstairs has a mix of microbore and regular pipework rads , the micro bore rads were drained individually and the regulars all drained from one rad.

I had every rad off in the summer and flushed each one with a hose pipe , they were filthy but all went back on clean , I added lots of inhibitor , its not been power flushed.

I dont know if the pipes from the unit to the boiler are sludged up , I would expect they are. How can I clean them?

I have read the posts on this site but didnt find anything similar ( apart from replacing pumps)

I will have a look at the Gledhill book ( thanks).

By running with pump head off , do you mean run with the silver centre removed ?I have done this and it drips but makes no difference.

There is water in the pipe above the pump when the boiler fires but the pump simply does not come in.

The boiler is 12 years old aswell its a Glowworm Ultimate and I dont know if it has a pump over run or not ( and I dont know what a pump over run is ).

So its a puzzle , I am a bit dissapointed that replacing the pump only worked for half an hour.

Thanks

No pump over run.
When the system was drained via the boiler, what was it like?
Brown?
Any lumps?
Did it drain quick?
Are you sure you have no air trapped. As that will stop a pump.
Is the BM III asking the boiler to fire? Is the boiler on max?
If the boiler is firing then the pump should run.
Is there a supply at the pump then?
When it all stops is the supply still there?
Is the vent on the BM III blocked?
Pump heads can be removed by 4 bolt with an allen key.
Have you vented the unit at the side?
Sometimes you have to loosen the top PHE pipe ( gently)
If the supply to the pump is not there then you may have to look at the ACB.
I assume you have checked the fault codes?
As the store sensor could be faulty.
You could try Google and look for some one in your area like myself.
If you and others put your areas then more offers of help may be forth coming.
Mike

Thanks for the ideas Mike.

I had an engineer out today from a London Company Heat Light and Power ( Keith) and he quickly found the fault on the PCB.

The PCB was not sending the signal to the pump to start when the boiler fired up , he has overiden this and the pump is on now 24/7 as a temporary fix.

New PCB orderered from Gledhill ( my 5th ) and when this is fitted all should be fine.

I think I will put cleaning agent in for a couple of weeks and then the inhibitor to try and prevent the sludge problem which is the bigest enemy of these systems.

Keith thinks the PCB may well have failed because the original pump seized.

Anyway thanks for your help.