strange fault on glowworm

[southcoastboile]

Mainly posting this to help someone out incase they come across this fault.
Anyone want to take a guess on this one:
f22 coming up would not go through ignition sequence just constant f22. (Overheat). Checked resistance on thermistors, o/h stat for continuity, cleaned condense trap. All okay.
replaced pressure sensor. Boiler fired, all okay.

called back the next day for f73. Never had this fault on this boiler and not in book. Phoned glowworm. Could be a few things but likely to be pressure related. Plugged in another pressure switch and manually pushed in diaphragm, not reading pressure. Checked continuity through all 3 wires on pressure switch from switch back to pcb. Found continuity on all 3.

This is were I started to get really annoyed. Any guesses to what the fault could be?

 

[Atouchofgas]

The impossible breakdown

What's the make and model? Should be in closed section?

 

[southcoastboile]

Re: The impossible breakdown

Thought this was closed section can someone move please? . Sorry yeah that would help. Glowworm flexicom (one with rectangular heat exchanger, probes on top and Fga test point inside and out).

 

[Billy Bob Bob]

now moved to gsr forum

 

[Riley]

F73 - unable to see pump activate. So could be more pump relevant?

 

[southcoastboile]

It was a stitch up in terms of fault finding. It was pressure related in a way.
i then changed the main pcb thinking it wasn't recognising the signal from the pressure switch. Still didn't work so replaced the display pcb thinking it was that. Still didn't.
turned out it was the wiring harness from the pressure switch to the pcb even though I had continuity through all 3 cables.
Retested old loom and still had continuity so would recommend bringing a harness just incase on an f73 fault. Makes no sense.

 

[Riley]

Good tip

 

[Atouchofgas]

Bizarre and random faults are the best. Not

 

[Riley]

I'd say 2 or 3 out of twenty are a sod

 

[southcoastboile]

I know. And how do You charge for
130 plus vat pcb
£17 plus vat pressure swich
£18 plus vat wiring harness
£86 plus vat display pcb
about 5 hours labour
hate faults like that

 

[Riley]

With a smile on your face !!! :cheesy:

 

[galaxy_plumbing]

i got this 2 weeks ago, stupid glow worm harness, kept giving me random faults, wanted to get hammer and smash it. :banghead:

 

[dave1]

I've had a few of these harnesses go. Funny enough got one to change tomo. A bugger to diagnose but a two minute job.

 

[galaxy_plumbing]

i was looped in f5, then f10

 

[dave1]

i was looped in f5, then f10

And it was the pressure sensor harness?

 

[southcoastboile]

All I seem do be doing breakdowns on is mainly glowworm a just out of warranty. Been doing around 5 a week if say for the last month. Mainly flat vessels, water pressure switch faults and no display because of the pcbs

 

[Riley]

All I get with em is clogged phexs. Considering all else in glow worms nice easy job

 

[galaxy_plumbing]

And it was the pressure sensor harness?

pcb was gone, that's what i was there initially but after boiler started went to f5 immediately so checked thermistors ans cables, all fine. mainly was getting thermistor fault, but havent change any cables as didnt have any with me anyway. boiler is fine so far, but i uncliped cables where they are fixed on control box so they were loose. i havent checked all of the for continuity just some.