Riello G5X "50V" Capacitor.

John.G

Riello G5X burner fitted in 15 year old Firebird Boiler was making buzzing sound which would point to a faulty capacitor, however I found that the fan was binding in its housing. I duly freed up same and burner fired up.
This burner motor is 50V and is started wit a 4UF capacitor, the original capacitor shown has a screw stud on its end which means it can be neatly attached to the fan housing.

My query is would any 4UF capacitor be OK to use if this one failed and a OEM spare wasn't available.

Energy monitor numbers from motor: 235V, 0.645A, 0.70 PF, 105.5W.

Edit: Got a bit mixed up, the motor is actually 230V but sends 50V to the control box so no query really.

whizbang

my experience would say yes, anything similar will work,

Generally I find the bigger the capacitor, the more robust.

I'll just add that the 50v is the max voltage it can take.
You could use a 4uf 100vor 4uf 200v etc if you can't get the 50v

John.G

BrownFinger wrote: »

I'll just add that the 50v is the max voltage it can take.
You could use a 4uf 100vor 4uf 200v etc if you can't get the 50v

As per my edit above, the motor is actually 230V, the 50V is generated in the motor via a transformer and is the supply for the control box, its one of the fault finding items if burner not working......"check for 50V on the white wire, if no voltage then replace the motor" any idea why the 50V is supplied this way and not from a external transformer?, maybe space saving?.

Back to the capacitor, the OEM supplied one seems to give a very very long life, mine is still going strong at 15 years and a relation has one +17 years. I read somewhere that the higher the voltage rating the better. This capacitor has 450V A, 475V B and 500V C with other numbers stamped on it, maybe this is of some significance regarding longevity, presumably there is a hour rating for different quality/grades.

brightspark

In general it is okay to replace a capacitor rated with one rated for a higher voltage. Unless you really know what you are doing you should never use one with a lower voltage rating.

A different value of capacitance (Farad) will affect the starting torque etc.

As regards the ABC values.

https://www.ien.com/product-development/article/20850180/understanding-selecting-capacitors

In this standard, different class ratings specify different field life for capacitors. The different class ratings depend on the amount of test hours that a capacitor goes through.

Class A specifies an applied life of 30,000 hours
Class B specifies an applied life of 10,000 hours
Class C specifies an applied life of 3,000 hours
Class D specifies an applied life of 1,000 hours

John.G

Mine based on its 15 year life and ~ 8100 hour (burner) run time might see my boiler out so.