Tearing hair out worc 24i junior lpg help needed :)

[TFGplumbing]

Problem: No CH or HW
Symptoms: boiler will not go through ignition sequence, when the boiler gets a demand from either ch or hw the nothing happens. if you go to reset the boiler the fan starts up on high speed for about 2 seconds and then nothing. The blue light on the front of the boiler is solid and its not locking out or giving any fault codes.


Worcester tech said its the pcb changed that still no joy they also suggested the transformer I'am going to try that today.

Tests worc tech told me to do:
I've tested the voltage to the fan which is ok
I've tested the resistance between the two wires on the flow switch which also ok
I've tested the resistance betweenthe two thermistor wires they were also ok


Any other bright ideas guys? this is really breaking my balls now lol


PS I am tearing my hair out. Also see my earlier post of how this all started




http://www.ukplumbersforums.co.uk/g...worc-24i-junior-lpg-fault-intresting-one.html

 

[SimonJohns]

My bet, its the fan

But haven't come across one like this before

 

[TFGplumbing]

Fan, transformer & pcb now, no changed same problem

 

[P J F PLUMBING]

Have you tested aps or cleaned Venturi

 

[Leo21]

Sounds like aps or duff pcb to me.

 

[P J F PLUMBING]

I think he changed the pcb I'd go for aps

 

[TFGplumbing]

How can i test the air pressure switch & Venturi? on this model

 

[Leo21]

Not sure about that model, but written on them is normally c, n/o, n/c. Which is common, normally open and normally closed. Get your multimeter on the common with the connections off and test continuity between common and normally closed. You should get continuity. Sure you can do it at the pcb connections, but you'll need the wiring diagram for it.

 

[Nostrum]

Have you checked the flue stat? I think a mate at work had a similar problem and worcester tech said it was the transformer, turned out to be the flue stat. From what he was saying, the stats are all wired in series via the orange wires back to the board. Worcester tech recommended buying every stat and trying them until they found the faulty one!

 

[P J F PLUMBING]

The aps is behind the fan I think it may be the flue stat Worcester's are hard work when they have a jiggly fault And who's to blame us the engineer loving worcster boilers !!

 

[Nostrum]

Not me, hate them with a passion with the exception of the Ri

 

[Leo21]

I really miss the days of cleaning pilot assembly's and thermocouples.

 

[P J F PLUMBING]

I hate faulty Worcester's love the challenge of stripping a bbu loads a screws ect then putting back

 

[TFGplumbing]

Well I used to love WB boilers until this one

 

[TFGplumbing]

Does anyone know what the resistance should be over the terminals on the flue stat?

 

[P J F PLUMBING]

I've got the mi in front of me. It doesn't mention the flue stat resistance

 

[TFGplumbing]

Nope i couldn't find it either, according to their fault finding chart its the PCB or fan!

 

[TFGplumbing]

Since the burner was flooded I believe that the flue temp stat would have been submerged in water, would that screw it up?

 

[Nostrum]

Good chance of it!

 

[TFGplumbing]

well why the hell didnt Worcester tell me this?! Iam sure all they have got at tech support it a large top hat full of bits of paper with boiler parts written on them, and they get a monkey to put its paw in this top hat and pick out a bit of paper.... and bam! thats how they decide what part is broken

 

[Nostrum]

Like i said earlier, they recommended buying every stat, 4 in total i think and changing them until you find the knackered one!

 

[TFGplumbing]

We tested the resistance over the two terminals on the flue stat earlier and got a resistance of 0.
I was just wondering is the resistance only 0 when the stat is cold, and once it reachs its ''danger'' temperature it actuates and then you get a resistance...

 

[TFGplumbing]

bump anyone? =]

 

[Millsy 82]

Test continuity on the 2 orange wires (I think) which goes to APS OH stat and flue OH stat if you do not have continuity then you have a fault try linking out flue OH stat and see if it will then light up then OH stat then APS (I always leave this until last as its a pig to get to and if the other 2 work fine you know its that) If it is the flue OH stat make sure you get the right 1 as there are 2 different types a screw in and a push in type as I once got a part number off worcester gave them serial number and everything they needed and they still got the wrong part.

As for their tech line they are worse than useless they just read through the fault finding charts which is like in the book if you ask anything else they dont have a clue.

 

[Millsy 82]

Actually I think it is the green wires