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B

broggo

Hi guys
Got a job on one of these.
1st call was no heating or hot water.
Tested fan and it was faulty.
Went to fit new fan and still nothing but this time there was no power to fan.
Luckily I had a spare PCB from a boiler I'd taken out a while back.
Fitted this then had power to fan again but still didn't work.
So I thought suppliers had given me a duff fan.
Went back today fitted the 2nd new fan
and still not working. Again no power to the fan from the board.
All the time the pump is running.

Please help as I'm puzzled.

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Never seen one in my life. Got a link to the mi's broggo? Is it a basic fan flue or condensing boiler?

First thoughts, by-the-way. Is there a pump flow switch present or does the aps have 3 wires to it? Sorry can't be of much more help without mi's 🙂
 
When you say you tested the fan and it was faulty, were you getting 240v there or did you check for correct resistance? Is there a high limit stat that has tripped? only the pump runs on most boilers when this occurs.
 
When you say you tested the fan and it was faulty, were you getting 240v there or did you check for correct resistance? Is there a high limit stat that has tripped? only the pump runs on most boilers when this occurs.

Checked for voltage initially, which was present.
Kicking myself for not testing the resistance.
Then when fitted new fan there wasn't any voltage. That's when I replaced PCB with one which I had in van.


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Never seen one in my life. Got a link to the mi's broggo? Is it a basic fan flue or condensing boiler?

First thoughts, by-the-way. Is there a pump flow switch present or does the aps have 3 wires to it? Sorry can't be of much more help without mi's 🙂



Just looking thru it now thanks pal



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Just looking thru it now thanks pal



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As bronzino mentioned a manual reset o'heat could be the cause too but doesn't sound as likely given the weird goings on with power to fan!
 
As bronzino mentioned a manual reset o'heat could be the cause too but doesn't sound as likely given the weird goings on with power to fan!

Sorry meant to say. I have a thermistor which I plugged in to check it wasn't that.


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Pump runs and nothing else and without any mi's I'd be looking for a pump flow switch or as said how many wires were on the room stat and checking it's operation! You had no joy getting into the gas safe area broggo?
 
Pump runs and nothing else and without any mi's I'd be looking for a pump flow switch or as said how many wires were on the room stat and checking it's operation! You had no joy getting into the gas safe area broggo?

I disconnected room stat matey.
Gas safe area?


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pump flow switch left hand side rear has a small square cover on plastic block that has a push fit copper pipe that goes across to the otherside of the boiler. It's a micro switch with a small thin pin,all very fragile & often faulty[ intermitant]
 
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Think Aggis hit it on head here.
Been a while since I have worked on one, but the flow switch may be faulty as mentioned.
Another thing to check is the very cheap and brittle plastic filter housing on left hand side. If this blocks it can reduce the flow pressure required to activate the flow switch. Flow switch must be proven for fan to kick in.
Be very careful as it is very delicate(crap). Use plenty grease on seal and don't over-tighten. Learned the hard way myself.
 
pump flow switch left hand side rear has a small square cover on plastic block that has a push fit copper pipe that goes across to the otherside of the boiler. It's a micro switch with a small thin pin,all very fragile & often faulty[ intermitant]

Tried that pal. Works fine 🙁
Gonna go back today and talk to Sime whilst I'm there.


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Update :
Rang Sime tech and they didn't know what was wrong.
Engineer came and met me on job and changed wiring loom pcb flow switch and thermistor.
Boilers up and running. We were both stood staring at the boiler asking each why?
Everything was showing signs of it working before parts were changed but it was having none of it.
I checked the wiring loom for continuity whilst he changed other parts and it was fine.
Strange one this!


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