Aico 3000 Range
This official sponsor may provide discounts for members

Discuss Wilo Pump Capacitor Replacement in the Central Heating Systems area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:  American Electrical Advice Forum

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.
 
uHeat Banner - Forum Discount Available
This official sponsor may provide discounts for members
  • Thread Starter Thread Starter
  • #3
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.

IMG_2621.JPG

IMG_2629.JPG
 

Charlie_

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

TJ Anderson

-
Mentor
Arms
Esteemed
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.
 
  • Thread Starter Thread Starter
  • #9
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

-
Mentor
Arms
Esteemed
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.
 
Last edited:

PEG

-
Mentor
Arms
Esteemed
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_

-
Arms
Capacitance setting on multimeter will give you its rating but you need to check its charge/discharge..
Do you have an anologue multimeter?
 
  • Thread Starter Thread Starter
  • #13
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.
 
  • Thread Starter Thread Starter
  • #14
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

-
Mentor
Arms
Esteemed
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.
 

PEG

-
Mentor
Arms
Esteemed
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.
Hi,i would hope the system is not pressurised,beyond the pumps specification,and there are gate valves each side of the pump...

What temperature does the glycol get to?
 
  • Thread Starter Thread Starter
  • #17
Hi,i would hope the system is not pressurised,beyond the pumps specification,and there are gate valves each side of the pump...

What temperature does the glycol get to?
No, the system runs at about 1.5 to 2 bar. There are gate valves on the pump. Problem is if I remove it, it is likely to lose pressure and I have no way to re-pressurise it. As for temperature - that can vary enormously (depending on the sun!). These systems can reach very high temps, though the controller shuts down if necessary to protect the pump. There is an expansion tank to cater for such situations.
 

PEG

-
Mentor
Arms
Esteemed
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.
Hi,i would hope the system is not pressurised,beyond the pumps specification,and there are gate valves each side of the pump...

What temperature does the glycol get to?
No, the system runs at about 1.5 to 2 bar. There are gate valves on the pump. Problem is if I remove it, it is likely to lose pressure and I have no way to re-pressurise it. As for temperature - that can vary enormously (depending on the sun!). These systems can reach very high temps, though the controller shuts down if necessary to protect the pump. There is an expansion tank to cater for such situations.
Hi,your picture showed signs of leakage,so i guess it has lost some already. There will be a means of filling the system....never seen one yet,that has not:)

What type of system is it,and what does it heat? I take it when you say "expansion tank" you mean chamber?
 
  • Thread Starter Thread Starter
  • #19
Hi,your picture showed signs of leakage,so i guess it has lost some already. There will be a means of filling the system....never seen one yet,that has not:)

What type of system is it,and what does it heat? I take it when you say "expansion tank" you mean chamber?[/QUOTE]

Hi PEG, yes there is sign of historical leakage but the area is dry and the system has held constant pressure for the five years I've been here.

There is a fill point but I don't have the kit to fill/pressurise it.

It heats the DHW, and yes I meant an expansion vessel.
 
Scolmore Electrical Products
This official sponsor may provide discounts for members

Reply to Wilo Pump Capacitor Replacement in the Central Heating Systems area at ElectriciansForums.net

SuperlecDirect - ElectriciansForums.net Electrical Suppliers
This official sponsor may provide discounts for members
Top Bottom