Heatslave tf832.3 control box burnout

[BillyRay]

Hello all,

Summary

Burnt out TF832.3 control unit - what could cause it?

Now Solved

Had the boys in to do a full shake-down and service. Sadly there were multiple issues including iffy solenoid, knackered diverter valve and actuator, slightly gummed jet and a possibly senile timer. Gutted it was so systemically unhappy but all is good now. When it reaches a certain point there's really no substitute for on-site experienced dudes.


The full story

Recently moved into a house with a Heatslave 26/32 oil burner.

Fired it up properly and tried to get some heating and water out of it (unclear if this was the first time it had been fully fired in a little while). couldn't get steady hot water out of it and heating was poor. Faffed about with temp controls and programmer, mostly it just kept stopping (no lockout light). Gave up and left the heating on the "on" setting and went away for the night.

Came back next day to find that it had tripped the fusebox and burnt out its 3.15a fuse.

Multimeter out, some further fuses later discovered that the tf832.3 has burned out. Ick, stinky.

So, replacement will be fairly simple, no worries there.

What's concerning me is root cause. Why has the control unit burned out and if I pop another one in, is the same going to happen again.

Thinking of things further down the chain - fan motor, capacitor etc.

Thoughts from boiler ninjas?

Thanks,
Will

 

[Terrywookfit]

Check the ign txfr.

 

[BillyRay]

Thx. Visual inspection enough for ign txfr? Do they just fail with time?

 

[Terrywookfit]

Check for an obvious blister. And primary winding short.
They usually overheat and go short for various reasons.
Poor combustion, Dirty MZ cell. faulty control box.

 

[BillyRay]

Thanks.

Looks ok - no obvious blisters, damage or stink.

Resistances:

Across input pins - 8.4M
Across outputs - 2.65K
Open circuit across any input and output pins​

Seems fine if those readings are where they should be.

Didn't want to cast aspersions, but the boiler was serviced last November (I only have a scan of the certificate to show that), so I would hope the combustion etc would be fine.

Will have a look at the motor capacitor at lunchtime.

 

[oilhead]

Isolate mains, remove control box, link mains input on base to live on transformer. Switch on power and see if it works. A similar method will also test the other components; don't forget the solenoid coil. If they all test out, then change the box.

 

[BillyRay]

Hi oilhead - by "control box" do you mean the 832.3 box? That nuked itself (or something nuked it - which is what I'm worried about), so I'm getting a new one of those anyway.

 

[oilboffin]

It might just be old age IMHO if the transformer goes then you look at the control box but if control box goes then really just replace.Bob

 

[oilhead]

Hi oilhead - by "control box" do you mean the 832.3 box? That nuked itself (or something nuked it - which is what I'm worried about), so I'm getting a new one of those anyway.

Exactly that. You use a live terminal into the base to link to the other components once you have made the connection and switched back on.
If you have a faulty component, you don't want to burn it out again.

 

[BillyRay]

Did some further tests - fan motor cap, flame sensor, spark leads. Everything seems ok.

Replaced the control box, been running like a champ for a few hours. Keeping an eye on proceedings. Will have a pro visiting tomorrow so can dig a bit further.

Thanks all for the help and advice!

Will.

 

[oilboffin]

A tap on the thanks button doesn't hurt.Bob

 

[BillyRay]

Donethanked.

Sadly spoke too soon. Everything was starting to get cosy indoors (ignoring hw issue, hex looks likely culprit there) but then cooled off. Went out and checked, boiler fan running, no flame, no lockout. Took front off, touched ebi, searing hot... now I suspect this piece. Wonder if ebi is ok when cool or summat... previously it was continually trying to spark while hot, failing until something reached a critical point and fried the controller.

Tetchy. Def. starting to think service in Nov was a nonsense.

Hopefully pro eyes/tools will solve (not the nov service guy for sure).

W.

 

[Terrywookfit]

Control boxes rarely fail for no reason.
If blown I normally fit a new EBI..Both can destroy each other..
As regards servicing .......We are not psychic in predicting component failure !!

 

[BillyRay]

Right enough Terry! Just when at least two discrete things (pretty sure the hex is blocked/knacked) go tits within a couple of months of an all-clear it makes me tetch. But then I suppose it's not been used much over those couple of months and maybe it's just bad luck.

Regarding the EBI, it's labelled 052F0037. According to heating parts, this is the same thing, would you concur?

https://www.heating-parts.co.uk/product.asp?prd=242499

ta,
W.

 

[Terrywookfit]

Yes but pricey.