Worcester Danesmoor 12/19 fuse

[Shieldaig55]

Hi , I have a Worcester danesmoor 12/19 oil boiler which ran faultlessly for about 8 years then started to "lock out" intermittently. This was eventually traced to a faulty ht lead but only after most of the boiler innards were replaced. I has run now for a further 18 months but has started blowing fuses, I replace the fuse and away it goes again . Perhaps for a day or 2 days or even a week - then blows the fuse again. When it is running the lockout light is usually on (but not a lockout) but the boiler continues to run ?? My heating engineer is puzzled and because most of the guts were replaced 18 months ago cannot seem to find a cause.

 

[Burnerman]

Its very important to use the correct fuse on these (3.15A fast blow if I recall).
Strange the lockout lamp is on but the burner is still performing....this would suggest a stuck relay in the control box to me, but hopefully Boilerman2 will see this one and advise you further!
John

 

[Shieldaig55]

Thanks for that ..... control box was replaced last time (18 months ago) and my engineer has again replaced it last week ... problem continues. Its blowing a 5 amp fuse ? should it be a 3 amp?

 

[Shieldaig55]

I meant to mention that the lockout lamp can fade/flicker and brighten from time to time but never really goes out.

 

[Boilerman2]

The orange light on the Satronic box can glow slightly, however if it is flickering & dimming/brightening I would be looking for a looose Nuetral connection somewhere?? the 3.15 TimeLag fuse is on the PCB, where is the 5a fues you are replacing is it in the Fused switch/spur connection??

 

[Burnerman]

I automatically thought it would be the PCB fuse
Thanks for the tip about the glowing lock out lamp - never seen that before.
John

 

[outinthestix]

Could also be the circ. pump blowing the fuse.
STIX

 

[Shieldaig55]

Thanks a lot guys .... very helpful, the pump does nt seem to be the culprit as the heating engineer had it stopping/starting with no probs. Loose neutral ? could be ? More investigation required, I'll have to get the circuit diag. out again. (I hope it's not the pump, it's under the floor !!) I'll post a note of what I find if anything. Thanks for all your help. Oh ... by the way the 5 amp fuse is on the spur from the mains.

 

[Shieldaig55]

Thanks for all your help guys - I'm afraid I'm no further ahead. There seems to be a pattern though, it pops the fuse usually about 2 to 3 mins after a cold startup. When the fuse is replaced the lockout light is "full" bright then gradually fades to a faint glimmer. If I'm lucky the boiler then runs OK stopping / starting on "hot" cycles. But then the same problem returns when it has to fire up in the early morning from cold. Could this be a thermostat switch? It's costing me as much in fuses as oil !!

 

[Boilerman2]

I'm very sorry to hear that your problems are continuing
it is VERY hard to make a diagnosis without being in front of your boiler!

However as this seems to happen after a "cold" start, it would be worth having a good look to see if there are any small water leaks that are dripping on to any electrical components, this would cause the problem you have, but once warm, some leaks stop or the water leaking evaporates and so the problem does not occur when hot

you really need an engineer that SPECIALISES in BOILER Repairs

 

[Shieldaig55]

Hi guys,
At last some developments - on Friday it blew the fuse again and did'nt come back to life when it was replaced(just at the start of the week end !!!) My heating engineer has just pulled it apart and found the capacitor on the motor with a sticky orange liquid leaking. Could this be the culprit ?? Here's hoping for a result this time.

I'll keep you posted.

 

[Burnerman]

Must be the start cap internally short circuiting.......who could have dreamt up that one?
John

 

[matt1e]

My heating engineer has just pulled it apart and found the capacitor on the motor with a sticky orange liquid leaking. Could this be the culprit ?? Here's hoping for a result this time.

I'll keep you posted.

yes.

Must be the start cap internally short circuiting.......who could have dreamt up that one?
John

the cap is probably not short circuiting John the cap is leaking electrolyte and as a result will lose capacidance which will result in the motor sometimes failing to start (depending on its rotor position)
a stalled motor will quickly overload and rupture the fuse (be aware this can also result in damaged motor windings due to overheating)

Matt

 

[Shieldaig55]

Hi Guys,

Right...... the boiler is now going, and without the 'lock out light' but for some reason will only run when the 'service switch' is set to 'service'. A lot of head scratching here so the engineer suspects a faulty wire in the loom between the control panel and the service switch. He was thinking the leaky cap was also leaking volts and causing the variation in the lock out light glow. Good news - no blown fuse so far ..

I'll keep you posted.l

 

[oilman]

"Engineer" seems to be a bit of a euphemism, otherwise it would be fixed by now. Also prone to pulling wool over peoples eyes when he doesn't know about leaking caps. I can understand thoughts like this from someone who doesn't know, but from someone who's getting paid it's not good.

For reference, there is no 3.15A fuse in the Danesmoor, it was used in the Heatslave. A standard mains fuse is designed to withstand twice it's rated current for 30mins, so don't use them for appliance protection. They are for cable protection.

The failure to run except in service mode indicates a missing output from the timer. Either the timer is faulty, or the connection is broken, A simple fault to diagnose.

As you have had so many parts replaced to solve this fault, maybe it would be worth paying Worcester to service it in future.