Bolier doesn't always fire up!

[dan83590]

I have found the microswitches (see pic). It looks like they are operated via a sprung plunger by a diaphram. With heating demand only the plunger moves towards the microswitches and when both are depressed the boiler will fire and heating runs. All fine there.

Now. With the heating on AND a demand for HW the plunger moves away from the microswitches at a good constant smooth speed. Now we turn off the HW and the plunger moves very very slowly back towards the microswitches and comes to a halt just before both switches have been depressed. So no flame, pump is running though. If I depress both switches by hand the boiler ignites.

I have for now made an adjustment to the two arms that depress the two switches and the system seems to work but this obviously will not solve the underlying problem.

What next or have I jumped the gun and done something I shouldn't have?

 

[twgas]

Usually if the diverter isn't making the microswitches it would be the diaphragm OR one or more bundy tubes blocked. seeing the state of your div valve I would be changing the diaphragm, bearing plates and seals, if that doesn't cure it I'd check the tubes for blockages.

 

[dan83590]

So you think the problem may well be in this area.. I'll strip it on the weekend and go from there.

Thanks for now though. If I need any more advice I'll resurrect this thread.

 

[twgas]

I've got one, doing the same as yours, to sort out tomorrow, I'll let you know exactly what the problem is/was when it's done - all the parts have been ordered so I should be okay.

 

[Netdragon]

I would also go with the diverter valve on the appliance as a possible source of the problem them boilers are prone to blocking up on the microbore tubing.

If the valve don't make the micro switches then i would go diverter valve / tubing but also check for other components (I would advise against it if you are not competent in gas).

Another item i keep in mind the black box on the left is your domestic hot water heat exchanger, this is looking a bit rusty and has had leaks in the past.

This item has been modified with a metal replacement kit in recent years due to the old one breaking down and leaking keep an eye on it as the appliance gets older, as the box next to it has all your pcb's

 

[twgas]

Netdragon, are you a RGI, if so the combustion chamber is worth joining, as a whole host of info is available there and gas stuff is discussed without having to worry about the general public doing unsafe things. See the second line on plumbing and heating home page for details.

 

[Netdragon]

Yes i am a "RGI" and deal alot on warmfront and "ideal" stuff ill have a look on that i poped on to see what kind of problems people been having and give some advice

Only problem is the Corg ID no corgi anymore someone needs to update board or will the gas safe stuff work?

to stop this guy getting help send us a msg if it will work ill have a look alter

 

[twgas]

GSR number is fine. Think we need to be friends to message.