I believe I have a Start/Run capacitor failure on my central heating system.

Can anyone help me identify what I should be looking at on the circuit boards please?

 

Any help appreciated as it's bl==dy freezing. :helpsmilie:

Run me through the symptoms.

Household/domestic gas boiler?

I have a Johnson and Starley hot water only condenser boiler. (HE25 H)

Initial I would get an error code on the control panel relating to... ( no tacho from fan. )

 

From there I was able to clear the code and the boiler would fire up, but after a couple of times it would not clear.

I did manage to start the fan by hand a couple of times also, but again can not any more.

The last time the fan did run it ran very slowly before dying completely but would not fire the boiler.

I am no longer able to clear the error at all.

Hope you can help.

Ah bugger nuts! That one's beyond me unfortunately. Sounds like a technical helpline or boiler specialist job. Have you tried hitting the fan motor with a hammer?

Sounds like the start of your problems is a faulty fan, until it reaches the required RPM it won't go to ignition or open the gas valve. Have you looked for the manual either at home or on the net at the fault finding pages?

 

Edit: just read your post properly lol maybe the technical helpline for the manufacturer might be able to point out which component of the PCB you may need but I'd be very surprised if they sell it separately as it's usually just a complete board so would have to be from RS or someone similar.

Edited October 15, 201411 yr by Baz

Thanks guy's.

 

As I understand it, because domestic voltage is balanced (single phase) the fan can not determine a rotation.

It takes a fluctuation of voltage caused by the capacitor responsible.

The start up capacitor takes part of the winding and uses it to start rotation, once up to speed the run capacitor takes over.

It maybe that both the start capacitor and run capacitor have both failed.

My problem is identifying them.

Once I have done this I will be able to replace the individual items.

The difficulty I have is determining the correct capacitors.

So far I have identified the circuit board symbols for them, -//- but the variety of capacitor is very varied.

If you're sure it's a capacitor and there are no obvious leaking ones; replace them all lol! It'll probably still only cost a few quid compared to a new board which is likely to be a few hundred!

If you're sure it's a capacitor and there are no obvious leaking ones; replace them all lol! It'll probably still only cost a few quid compared to a new board which is likely to be a few hundred!

 

So if I was to look at each one, I should be able to see signs of leaking/damage which in turn would help me to identify the faulty ones?

So if I was to look at each one, I should be able to see signs of leaking/damage which in turn would help me to identify the faulty ones?

 

You can generally tell a dodgy capacitor as they tend to "fizz". A quick google showed a few images but here's a random one:

 

I'm no expert though, someone more experienced with electronic components like this could probably give some more detailed advice.

There is a fix on Hotpoint washer pcb and that is to replace a certain capacitor with a larger one, sounds a very similar thing.

 

Washers and boilers will only get so far in their cycle/program before indicating a failure to the user but you know that.

 

It also sounds to me that it was intermittant to start with, have you checked every spade connection, often with great heat things begin to crumble/corrode.

There is a fix on Hotpoint washer pcb and that is to replace a certain capacitor with a larger one, sounds a very similar thing.

 

Washers and boilers will only get so far in their cycle/program before indicating a failure to the user but you know that.

 

It also sounds to me that it was intermittant to start with, have you checked every spade connection, often with great heat things begin to crumble/corrode.

 

Yes mate, have checked every connection. I will double check tonight as well just to be sure.

Thanks for the input. :thumbup1: