Ideal Mini C28 - doing my head in..

[defonarival]

I have an intermitten fault on my mini C28 boiler, it keeps failing to fire sometimes upto 6 times a day or it can run for a few days and decide not to fire. The pump and fan both are both running and the microswitch makes but it won't fire. I turn the boiler off and back on and it fires up! The boiler is not locking out but the green light flashes very fast - Am I looking at a new PCB?
Someone out there can help please?

 

[transam]

there might be a problem with your primary flow switch , a fast flashing light 4 pre sec ?? can indicate a primary flow prob' . the green light is part of a 3 light fault finding system , the other 2 lights are behind the left hand side electrical access panel.

 

[defonarival]

yes there are 2 green lights flashing and the red light is on

 

[transam]

2 x flashing lights & the middle red light on , no ignition signal from the ignition pcb , the ideal mini c is actually a rebadged biasi boiler , there are 2 pcb's in this boiler the ign pcb is the one on the right , the one on the left is the contol pcb , which supplies , or powers the ign' board

 

[defonarival]

Thanks transam - would the PCB act intermittent? Had a local installer take a look a couple of weeks ago and he replaced the fan as he said it was sticking and I don't want to spend again without being sure. All the tests done say the boiler is working fine and someone could be here all day waiting for the fault to occur!

 

[shambolic]

Just be careful as depending on version and serial no some of the later mini se boilers have a single pcb not two.
If you can see all three lights from the front without having to take off pcb covers then you have the single pcb part no 174500. Also the detection and ignition leads can short onto each other if really tight in cable clamp.

 

[Pinkypanthers]

Had similar if not same problem recently on a biasi 28 kw.

Red light on 2 flashing green lights.

Pump ran but no power to fan.

Didnt have continuity on the air pressure switch n/c connections so replaced air pressure switch, boiler fired up ok but had intermittent fault afterwards.

I Found in fault mode, that there was no power from main pcb to ignition pcb, which is basically a connector from one to the other. Easily tested bottom brown wire on the connector link, check for live on the ignition board side.

I change the main board and the boiler is now history.

Hope this helps.

 

[defonarival]

thank you all for the response - there are 2 boards so an earlier model.
I have called Ideal technical team and they pointed to 2 potential causes.
1. Sticking Gas Valve <--would this go to lock out?
2. Bad flue seal
either way it looks like I may have to get the engineer back to check both these!

 

[shambolic]

Not sure of thgose diagnosis mate, I would look at high and low pressures set on gas valve and ignition pressure(set on board).
Flue seal is a mibbee but not convinced on this problem check the wires thing I had previously posted then look at repacing the ignition pcb right hand board.

 

[defonarival]

Thankyou Shambolic, I decided to check the wiring on the board as your detail and as you can see in the image the board is not in the best shape. So much for the help at Ideal!
I'll let you know if a new board solves the issues.
Thanks again

Untitled

• defonarival
• 16 Dec 2009
• 1

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[Agile]

That PCB looks fine to me.

There can be so many causes of intermittent FF lockout that its not worth guessing but I find that 90% are a faulty ign PCB.

But as thats expensive then obvious its sensible for a competent engineer to eliminate the other possibilities first.

The fan was not likely to have been any problem.

Tony

 

[Minxy]

I have got exactly that same fault on my Ideal mini C28 boiler, i have had engineers out to check wiring, corgi engineers to check the flu seals etc all were deemed ok, Now sometimes the boiler is fine for a couple of days and others it cut off from 2 up to 12 times per day and then decides to works ok for a short while.

Can anyone offer any advise on fixing this boiler, it appears to be exactly the same issue for defonarival.

I hope someone can help me.........

 

[matt1e]

that pcb may not be ok (you need to turn it over to inspect) and its too late to reply fully as im off out but go here
same pcb same probs same solution 9 times out of 10

matt

 

[defonarival]

It was the PCB got a replacement and boiler worked fine all over winter - thanks all for your help

 

[sadders]

My C28 is doing exactly the same as mentioned. Is this a common fault with these boilers.