That s*dding boiler again.....

[Moonmaiden]

Having a enjoyed a lovely couple of weeks of fully functional boiler and delicious hot showers, it's up to it's tricks again!

So to recap.....Ravenheat CSI 85T... in the past couple of months has had a new pump, new heat exchanger, new diverter valve and thermistors.......

Woke this morning to freezing cold water!

Came home from work to tepid water!

Went to have a shower this evening... back to freezing water.

The boiler works fine... fires up as normal and works the central heating.

When a tap is run with central heating off.... plunger comes out, microswitch engages and 'clicks' but electronic ignition does not kick in and boiler does not attempt to fire. (also tried by operating the microswitch manually)

Tried the same process with the heating on.... when the tap is turned on, the flame cuts out and then reignites as normal but the water is only tepid. When the tap is turned off the flame remains on.

Any ideas? I'm rapidly running out of hair to pull out...!!!

 

[Agile]

You seem to have had a lot of new parts to cure one fault!

Dont you think someone with good diagnostic skills would be better?

Tony

 

[Moonmaiden]

I think this is a totally new fault Tony...

Previously, I had a cycling on/off problem with the boiler during operation of the hot water but at least the boiler was firing on demand for hot water.

This was diagnosed as a problem with the heat exchanger and certainly replacement of this part appeared to cure this particular problem.

I also had the the diverter valve replaced at the same time as I had noticed that the bathroom radiator was getting hot during operation of the hot water... figured it was probably on it's way out and it would be cheaper to get the engineer to replace it while he was in there doing the HE rather than wait for it to fail completely.

A week or so later the on/off problem reoccured and was fixed by replacing the CH thermistor, which I did myself.

The problem now is that the boiler does not even attempt to fired on demand for HW. The plunger comes fully out and 'clicks' the microswitch (also tested manually using a screwdriver) but the boiler does not appear to get the signal to operate the ignition. Nothing wrong with the ignition however as it works fine for the CH.

I am a single parent and was made redundant a month ago. I don't have the cash to be throwing about calling in the 'experts' every time something goes wrong. If it's a problem that i can fix myself I do that.... and if it's something that requires a little more skill and know-how, I call in the engineer/electrician/mechanic/plumber/...etc

I was under the impression that since this forum had the letters 'DIY' in it, that the objective was to support people attempting to do just that...?

 

[Moonmaiden]

Forgot to add..... on a couple of occasions, the hot water did fire up for a short time but was ony tepid. Currently not firing at all even with the CH on. If the heating is on when a demand for hot water is made, the boiler cuts out (as is normal during switchover) but doesn't reignite.

 

[Boilerman2]

Some of the Giononni Diverter valves have two micro-switches in the microswitch housing one for the pump the other for the burner it is possible that one of the microswitches inside the black housing is faulty??

 

[Moonmaiden]

I did manually test the microswitch.... with the heating off, depressing the HW switch causes the pump to kick in but the boiler does not fire up. With the CH on, depressing just the CH shut off switch the boiler does cut the flame so I assumed the switch was ok... although could there still be a problem with the switch? It is brand new and came with the new diverter valve which was only fitted about 3 weeks ago.

I have ordered a couple of new thermistors since these are only cheap and seem to go very quickly on my boiler.... never harms to keep a couple of spares in anyway! The CH one was replaced 2 weeks ago but I was wondering if maybe it could be the DHW one this time?

 

[Boilerman2]

Check the wiring between the Microswitches and the PCB it may not be wired correctly, when the diverter m/switch is depressed manually the pump should run and the Burner should fire up

 

[Moonmaiden]

Check the wiring between the Microswitches and the PCB it may not be wired correctly, when the diverter m/switch is depressed manually the pump should run and the Burner should fire up

If it was wired incorrectly, would it have been working for the past 3 weeks ok? BTW, it was fitted by a gas registered engineer not me!

 

[transam]

Thermistor problem ? u have a couple on order give that a try ??

 

[Moonmaiden]

Well... woke this morning to find the boiler working perfectly. Grabbed a hot shower while the going was good.... and it still seems to be behaving itself and giving hot water on demand!

Would this suggest a dodgy connection somewhere perhaps? I am reluctant to reassemble and put the front panel back on until I know that the problem is fully resolved.

 

[Moonmaiden]

Went for a shower this evening and it's up to it's old tricks.... dry tested it with the new thermistor which arrived this morning and hey presto... hot water..... put it back on the old one.... wouldn't fire up. I think we've found the culprit!!

Tomorrow morning I shall be throwing caution to the wind and fitting it!

 

[Agile]

All of these guesses could be bypassed by having a cheap multimeter and knowing how to use it to check switches and thermistors.

Tony