Ignition problem - Ferroli Optima 901

[JimB]

I fitted some new rad's in my house today. Unfortunately I can't heat them up...

I repressurised the boiler, bled the rad's, and started the boiler light up as per Ferroli instructions. No joy. I heard a relay clicking for about 10 seconds before I powered off the boiler.

On my second attempt the relay only clicked once or twice and the boiler appeared to behave normally. After waiting for the three minutes before the fan was supposed to kick in nothing happened. I have removed some covers and done some multimeter testing/visual observation

- the pump is circulating as expected
- the fan does turn - when I first power up the boiler (for a second or two) then if e.g. I turn on the hot tap.
- there's no ignition spark, ever
- one relay seems to click sometimes on boiler powerup. It's the one closest to the mains transformer and appears to be connected to the pump (although I can't be sure)

Until today the boiler has been working trouble free for five years (since we bought the house)

My gut feeling is that the PCB has developed a fault, but how can I be sure, before I shell out 200 quid or so, that something else isn't gubbed? What other testing could I do?

If you have any suggestions, need any further information, or can supply the name of a good reputable repairer in Lanarkshire please post here.

Looking forward to your help and getting some heating on again.

Jim

 

[meldrew's_mate]

It sounds like you've already had the boiler partially in pieces already.

Have you visually inspected the PCB for signs of racked solder joints, especially around the relays?
Otherwise inspect the fan is running properly, not partially seized, then check the air pressure switch is operating properly.

 

[JimB]

Wow!

Thanks for the response! Much appreciated.

The fan turns, albeit slowly, and doesn't appear to be seized in any way.

I haven't removed the PCB but will do when I get my fingers thawed out.

How do I check the air pressure switch as you suggested?

Thanks again!

J

 

[JimB]

Hi Again,

Now have the PCB in front of me. There are a couple of dry joints which I'm off to solder. Look like resistors - 330 ohms according to the rapco resistor identifier.

These look like they've taken a pounding. Either before the dry joints started playing up or afterwards. Lots of heat marks (brown burn marks) on the upper surface of the circuit board.

Is this likely to be the problem?

J

 

[meldrew's_mate]

Heat marks can be considered normal, you're looking for black rings around the component pins on the non-component side of the PCB, these are signs of previous arcing which oxidise the joints and eventually cause them to fail.

Re-solder the joints you found anyway, it can't do any harm so long as you don't use a blowlamp and it MAY solve the problem if these are fan speed limiting resistors.

As for the Air Pressure Switch (APS) blow gently into one of the two tubes and listen for the click, if not suck gently. The APS checks that the fan is running before the ignition is sequenced.

Have fun

 

[JimB]

meldrew's_mate,

Many thanks for your suggestions, encouragement and guidance.

We're up and running again. It turned out to be the relay which when dismantled and cleaned powered up the fan at full speed.

It's -2C tonight and we're delighted to get our heating back.

If there's anything I can do to repay you please let me know. I have a bit of computer and software experience and if I can assist you drop me a PM.

J

 

[meldrew's_mate]

If there's anything I can do to repay you please let me know. I have a bit of computer and software experience and if I can assist you drop me a PM.

....unless you're a girl with big TTs I don't think there's much..... or have you a few days spare to talk about Windows Bloody XP interfering in my life. Bring back DOS.