Glow Worm Swiftflow 100 - No Hot Water

[Russ02]

Anybody familiar with this problem, please help.

The hot water side & the green light will fire up sometimes on opening the tap but not always.
When it doesn't fire up I close the tap & flick the elec power switch on & off a couple of times until the green light flicks on as I do it.

Then open hot tap and it will work & may continue to work for a few hours until it fails to fire up again.

It will sometimes knock off while running, eg half way through a shower, not funny when it suddenly goes cold.

The fault chart suggests it's the User control pcb?
I had a CH man take a look & he thought flow switch?

Both items approx £120 each & sods law says do one & it'll be the other.

The boiler is near 20 years old so is it worth spending on or do we need to bite the bullet?

 

[45yearsagasman]

View media item 68293 That would be my suggestion. You may get away with a £120 repair bill, but what's next on a 20 yr old boiler. They were fairly decent though.

 

[Russ02]

You could be right gasman. On the good side this is the only fault we've had with it.


Best guess as to the fault?

 

[bazdaman]

I had an estate of these and no hw was usually a bad connection of flow switch to pcb top left of pcb red wire i think, only replaced one or two flow switches on them they are pretty solid

 

[Russ02]

I had an estate of these and no hw was usually a bad connection of flow switch to pcb top left of pcb red wire i think, only replaced one or two flow switches on them they are pretty solid

Thanks Baz,

I'll check that out. Is that wire from the user control pcb or the main pcb?

 

[bazdaman]

Main pcb

 

[Russ02]

Main pcb

I should have asked, where have you found the bad connection?

At the PCB or the flow switch end?

And the cure?

 

[bazdaman]

Pcb side make sure the plastic connector sits on pcb ok and the wires are pushed in to the connector. They are tight on the wiring harness and seem to work their way off.

 

[bazdaman]

http://www.ultimatehandyman.org/PDF...flow-100-installation-manual-47-313-08-07.pdf

Pg 44 and 45 and 46 shows where it is connected, the pcb housing is screwed to chassis from from only unscrew the screw and it sort of unhooks off

 

[Russ02]

Pcb side make sure the plastic connector sits on pcb ok and the wires are pushed in to the connector. They are tight on the wiring harness and seem to work their way off.

Ok thanks Baz, I'll check it t'morra.

 

[Russ02]

Hi Baz,

Thanks for the instructions, I located the 2 red wires on the PCB connector, like you said very tight from the harness.

The connections appear sound enough in the plug, pulled the plug, give it a squirt of wd40 & re-fitted it. Couldn't see any poor connections.


The bit that puzzles me is; sometimes it works, when it doesn't, a flick of the elec switch gets it to kick in? Then it might be ok for a few hours or just a few minutes.

 

[Agile]

It really does sound like a PCB fault. But these are getting pretty old now and ripe for replacement.

The flow switches can fail but that does not sound like your problem.

How a new flow switch can cost £120 defeats me! I would expect them to be about £30 ! They are a pig to change though.

As the fan runs constantly with the pilot the boiler really does need a proper service at least every year.

Failed fans are the most common fault I see on that model. That needs an RGI to replace.

Tony

 

[bazdaman]

Sometimes taking the plug on and off works wonders it's dark magic at work, if problems persist I would be turning power off and do a continuity test across red wires pcb end run tap and u should have continuity if it drops out intermittently then replace flow sensor, what's the flow rate like?

 

[bazdaman]

As tony said pcbs are flaky and have been redesigned solid boiler and at 120 I would think about changing boiler! Bloody hell didn't know they cost that robbing gits is it Honeywell or sit set up?

 

[Agile]

The price quoted is what the OP has been told by the RGI. He charges what he chooses!

Having said that it sounds about right for the PCB.

But not at all for the flow switch.

I agree that the ( actual ) contact resistance of the flow switch should be measured but few RGIs seem to want to do that.

Tony