pump capacitor problem

[Gary80gas]

Hi all,
I have a Grundfos pump with 240 volts, not jammed, runs each day for approx. 30mins-2hrs then stops. Capacitor looks ok but wire dropped out I put it back and pump running again 30min -2hrs according to owner.

Could this just be the capacitor needs replacing? I don't have capacitance reading on multi meter.
Where can you buy replacement capacitors? I looked online and hit brick wall. (2uf and 400volts)


Any help- thanks in advance

 

[ShaunCorbs]

normally the cap is only used for start up if if its cutting out and tbh there not worth trying to fix unless its a special on just change the pump

 

[Best]

I am not saying it is, but that can also happen to circulating pumps if they have magnetite in them. They often start when cold, but jam when they get really hot.
Motor windings do fail when hot also.
If it is capacitor, try Grunfoss themselves, or an electrical supplier

 

[rpm]

Suggests wiring breaking down or possibly bearings damaged causing drag / friction doubt it`s worth try to save imho.

 

[jtsplumbing]

Time you waste chasing around quicker to replace pump

 

[thompsonbrown]

Sounds more like cutting out with thermal protection of the pump.

 

[gassafe]

normally the cap is only used for start up if if its cutting out and tbh there not worth trying to fix unless its a special on just change the pump

I thought that but I'm sure when I said it once someone suggested a grundfos type pump used the capacitor as constant running speed or something??!

 

[ShaunCorbs]

I thought that but I'm sure when I said it once someone suggested a grundfos type pump used the capacitor as constant running speed or something??!

im sure these new modulating pumps have a constant cap as they need to keep changing there speed

so you might be half right havent had chance to take one apart/stripdown

 

[thompsonbrown]

I thought that but I'm sure when I said it once someone suggested a grundfos type pump used the capacitor as constant running speed or something??!

Capacitors usually installed for current needed to start up pump, as running current is around 8 times lower. But will check it out to be sure.

 

[rpm]

Sounds more like cutting out with thermal protection of the pump.

From damaged windings and or damaged bearings or pump running against a restriction are the 3 most likely causes.

 

[ShaunCorbs]

 

[oz-plumber]

Motor start capacitors - up to 330 volts. - generally metal cased.

Motor run capacitors - 400 volts and up - generally plastic cased.

I posted a link to this somewhere earlier.

Re: Pumps.
I carry a heap of capacitors when doing service works. A fair percentage of pump problems I find are capacitor problems.
Get a multi meter that can check capacitance.

You will end up making the same labour amount testing and replacing a capacitor as you would a pump changeover.
Plus you will make about 500% mark up on the capacitor.
( Getting into Rays territory there - better watch myself )

 

[Sparkgap]

Single phase induction motors require a capacitor to start or start/run depending on motor type. For most, the capacitor is there to energise a second winding in the motor to produce a rotating magnetic field and hence turn the motor. If the capacitor is breaking down you won't get the rotating field and the motor will stop.