Combi water pump - will it still work?

[Chudley]

Hi,

Last night the water pressure sensor on my combi boiler (the lamentable Chaffoteaux Britony SE80) fell off. Turns out the screw body that attaches it to the water pipe was made of plastic that had aged quite badly. Unfortunately this is the one thing sited directly above the pump, so the first we knew about it was when the pump shorted out and the mains MCB tripped.

It appears to have dried out now, and the resistance across the motor (from the PCB connector, detached from PCB) is 160ohms exactly? Can anyone tell me if this is normal, or should I purchase a new pump along with the pressure sensor? I'm eager to get hot water and heating back on ASAP so would prefer not to have to wait again if it doesnt work.

Thanks

 

[kevplumb]

you could try connecting the pump to a flying lead 3 amp fuse

that way if it does go bang it wont take the pcb out

if it hasn't already

 

[Chudley]

Thanks for that Kev - will definitely try that. The PCB looks fine & still powers everything else correctly with the motor connected, so fingers crossed it will be fine.

Ben

 

[Chudley]

Well, replacement parts arrived and are now fitted. I've had to take the pump head apart to drain out the water which entered it & have dried it out.

Having refitted the pump head and refilled the system it all worked fine for about 30 minutes then the pump stopped working. Removing the bleed screw it appears that it isn't spinning, although if you push the motor spindle inwards it starts to spin until it settles back forwards and stops at some point shortly afterwards.

At first I thought it was just air needing bleeding but this hasn't helped. Any ideas what's up? Should I just buy another 15/50 pump head (assuming that any generic Grundfos 15/50 pump head could be used here?)?, or is there something I can try to fix it? The spindle rotates without any effort so isn't jammed.

Thanks in advance

 

[Chudley]

Having tried to dry the pump out further just in case it worked fine for about 5 seconds after switching back on, then settled back to a very weak output. I can easily stop the spindle rotating with a screwdriver in the bleed screw. Pretty much sure it's had it now so going to have to replace.

Damn annoying place to put the only sensor on that stretch of pipe. At this rate I'll be a qualified Chaffoteaux engineer soon - the only advantage to owning this P.O.S.

Ah well.

 

[wilder74]

Have you 240v at the pump?

 

[tonybhoy]

You can buy an Myson pump head only kit that comes with a Grunfos kit which enables you to fit the head to a Grundfos 15/50 body and kit to fit it to a CP53 body.

Cost is £30.

MP53E Pump Head Only Kit.

Cheers,

 

[namsag]

Changing one of these pile of sh#te boilers tomorrow for a mate it is about 5 year old and falling to bits.
OH and don`t use a myson pump they are worse than the boiler

 

[kevplumb]

200000 bg customers cant be wrong

 

[Chudley]

Hehe.. This one is about 6 years old and so far I've replaced the PCB due to failure, replaced the water control module, replaced the diaphragm on the 3 way valve, and now all this. Absolute sh1te. But having spent this much it's too late to just pull it out and replace.

Incidentally, there is 240v at the pump, it's just not doing much with it. It worked after refitting again last night for about 5 seconds then that was that, back to the now usual 'to weak to push water round the system', causing the boiler to overheat. Can't say I'm surprised given the amount of water that was covering the windings.