Yet another combi problem: CH but no hot water?

[Skooter]

Hi,

We've recently moved into a new house last weekend. When i say new, i don't mean brand new.....it's 111 years old *lol*

Right, to the point. It looks to me as if the guy we bought the house from fancied himself as a bit of a DIY'er & has installed the heating system himself.

We've got a Ideal combi boiler, model C80FF & a Drayton Digistat 3 thermostat. The radiators & plumbing all look fairly new.

The first day we moved in, the radiator in the living room fell off of the wall. I put it back up & it fell off again This proceeded to cause a leak on the joint from the exit of the radiator, which resulted with a plumber friend welding in a new joint. Sorted.

It's a few days later, and now the hot water from the taps has stopped. The central heating is fine, but when you run any hot tap, the flame inside goes out straight away& the water is stone cold. You can hear the boiler switch from heating to hot water & you can hear it trying to light, but it just can't. I've bled all the radiators, and as far as i know the pressure on the boiler is fine (1.5 bar when cold, 2 bar when hot)?

I've just spent the last 6 weeks living with my GF's parents & now have to go back there daily to shower.....please help me!

I'm thinking along the lines of the flow switch? When that new joint was welded in, could this cause some dirk etc to dislodge & block this?

While i'm having a winge, that Drayton thermostat is a blooming nightmare to suss out how to work *lol*

Cheers,

Scott.

 

[breezer]

i know i shouldn't laugh (radiator fell off the wall) but that was funny. sorry

 

[oilman]

I'm thinking along the lines of the flow switch? When that new joint was welded in, could this cause some dirk etc to dislodge & block this?

No, the flow switch is in the coldwater feed from the mains, and nothing to do with the radiators.
The problem with the lack of hot water might be the heat exchanger being scaled up. Look up some of the other posts on the forum for further info.

 

[Skooter]

Heat exchanger? I'll do a search for it, cheers matey.

I've read people posting similar problems are being told things like 'themo-coupling', 'valve head motor', 'diverter valve' & 'water flow diaphragm'

Damn, why didn't i become a plumber!

 

[BDL]

I would suspect the dhw flowswitch, the c80 has 2 1 is used as a pump proving/chtg switch and the other for dhw. You need to contact a corgi reg engineer to diagnose the fault. The C80 is a badged biasi boiler and uses some very interesting logic in its 2 pcbs.

www.boiler-diagnostics.co.uk
corgi 201164

 

[Skooter]

I would suspect the dhw flowswitch, the c80 has 2 1 is used as a pump proving/chtg switch and the other for dhw. You need to contact a corgi reg engineer to diagnose the fault. The C80 is a badged biasi boiler and uses some very interesting logic in its 2 pcbs.

www.boiler-diagnostics.co.uk
corgi 201164

Thanks for the info mate.

But what do you mean by 'interesting logic'?

On a plus point, our hot water started working again last night. It seems that once the radiators are up to full temps, the hot water works. If i try running hot water when the rads are cold, the boiler won't ignite. Haven't tried it yet with the central heating off yet though.

We've got a British Gas engineer coming out tomorrow to inspect the system, as we've changed our service contract to our new house. Hopefully get it sorted once & for all.

Still haven't a clue how that Drayton Digistat works though?