Ideal mini C24 not firing

[gordon50]

Not sure if this has been covered before but my boiler is struggling to fire up in the mornings.
It's an Ideal c24 mini, recently replaced the exp tank and pressure relief vavle, but noticed that on starting up the plunger comes out of the diverter valve to activate the switch, then backs off a bit about, 1mm, but this de activates the switch and therefore won't fire up. I replaced the diaphragm but still no joy.
So I stuck a 1mm strip of plastic to the switch arm, worked fine for a few weeks, then I had to stick ANOTHER strip of plastic to the switch as the plunger was backing off a bit more.
This did the trick for another few weeks, and now it's playing up again, the plunger is backing off even more and I don't really want to stick yet another piece of plastic on the switch.
I have to keep switching it off and on again at the plug, about 6 or 7 times before it fires, I can tell when it will fire as I can hear the fan cutting in, once fired up it switches off and on again all day with no problem, it's only in the mornings that it plays up. Pressure is always on about 2 bar.
The main question is why does the plunger come out to the switch then back off almost immediately?
Any ideas would be greatly appreciated. Gordon

 

[Agile]

I have to say that I am not impressed by your attempts at bodging a safety device.

My advice would be to get a competent boiler engineer to deal with it.

But I would also admit that many will be somewhat struggling with that fault on that model.

Tony

 

[gordon50]

I don't you fully understand what I've done, I haven't bypassed this switch, all I've done is packed it out by 1mm. The piston is coming out 10mm, then backing off 1mm, so it's still out and pushing against the switch.
What I was asking is, does anybody know why this would happen.

 

[Agile]

On that model normally due to dirt in the system reducing the effect of the pump pressure on the differential flow device.

Most would define what you have done to your switch as bodging a safety device.

But if you don't agree than you can ask Ideal what they think. I suppose they might consider that to be a user adjustment although I doubt it. The usual rule is that manufacturer's safety devices should not be tampered with.

Tony

 

[shambolic]

I actually agree with Tony!!
Well flabber my gast.
That switch is to protect your boiler from overheating and being damage if there is insufficient water flowing through it.

 

[gordon50]

Ok, I got the wrong end of the stick, I thought this forum was about competent DIYers getting and giving advice!

 

[AGAS]

YOU THOUGHT WRONG THEN , you got the advice

 

[shambolic]

DIY ers shouldn't be working on boilers if not qualified. I think that's the advice.

 

[Murray90]

Was it the pump lol

 

[shambolic]

Was it the pump lol

Don’t know as it was over 2 years ago