Wilo Pump Capacitor Replacement

[Marko!]

Hi All, new member here.
I have a Wilo Gold RS50 pump fitted to a solar thermal system. I suspect the capacitor is faulty and wish to replace it. However, I cannot see the method to disconnect one of the capacitor leads (sited between the L & N connections). It is very tight and I don't want to damage the connection such that I cannot install the new one.
The other capacitor lead is held in with a clip and is easy to remove.
Any advice appreciated.

 

[telectrix]

a picture would help.

 

[Marko!]

a picture would help.

Indeed. I have one of the pump itself and one of the connectors. The 3 core flex and one of the leads are push fit, it's just the one between the L & N that I'm having difficulty with.

 

[telectrix]

maybe cut the lead/s and joint to new cap?

 

[Marko!]

maybe cut the lead/s and joint to new cap?

I did wonder about that. I reckon there is just about enough room.

 

[Charlie_]

Do you know how to test the capacitor once you have snipped the wires?

 

[TJ Anderson]

Unlikely OP will have meter which measures capacitance. OP, Remove the screw at front of pump with large flat screwdriver. Some water will run out so have a towel. With pump powered turn the shaft clockwise with screwdriver. If it spins up, replace capacitor.

 

[Marko!]

Do you know how to test the capacitor once you have snipped the wires?

I have an auto-ranging multimeter that can measure capacitance.

 

[Marko!]

Unlikely OP will have meter which measures capacitance. OP, Remove the screw at front of pump with large flat screwdriver. Some water will run out so have a towel. With pump powered turn the shaft clockwise with screwdriver. If it spins up, replace capacitor.

Thanks. I have done that already. It spins very freely. The pump will run but is reluctant to start as soon as it is powered. It will eventually start and run. I believe the capacitor is a run capacitor. It is 2 microfarad, 400V.

 

[ruston]

It's not just gunged up with slime is it . Has the system had inhibitor in it and flushed regularly?
I had one once that had a film of slime on the faces, it was on an old indirect system though with no inhibitor.

Sorry I've just re read the OP and seen it is on a solar system.

 

[PEG]

Depending how important the job is,it's doing,i would be tempted to fit a new pump.

You can experiment with the old unit,once everybody is warm

 

[Charlie_]

Capacitance setting on multimeter will give you its rating but you need to check its charge/discharge..
Do you have an anologue multimeter?

 

[Marko!]

Capacitance setting on multimeter will give you its rating but you need to check its charge/discharge..
Do you have an anologue multimeter?

Thanks Charlie. I have a Kewtech 116. I have seen advice on charging capacitors and how they should react but don’t have a flashy device to test for that.

 

[Marko!]

Depending how important the job is,it's doing,i would be tempted to fit a new pump.

You can experiment with the old unit,once everybody is warm

PEG - this is on a solar thermal system so swapping the pump out is a bit more complex due to it being pressurised with glycol.

 

[Richard Burns]

Based on the other connections I would expect the capacitor connection to be a push in connector, it is possible (if it is not just part of the moulding) that the tag just beside the cable entry may, if pushed either in or sideways, release the cable. Alternatively there may be a small hole on the other side of the block where a wire or terminal screwdriver may be inserted to release the cable, failing that a small screwdriver might release the cable if inserted beside the wire, but may wreck the terminal. Also possibly pulling and twisting may release it but this has the potential for causing problems if it is fine stranded wire and this is not a release method.