Baxi Bermuda Inset 50/6 - PCB failure

[mitch2000]

A month ago I had the above back boiler installed and since installation it has had four PCB's fail. Engineers on the following visits have:
1 Replaced PCB.
2 Replaced complete Burner Tray Assembly (PCB, Thermistor, Heat Sensor and gas Valve)
3 Replace another PCB
4 Replace another PCB and replace 3-way motorised valve, as thought switch may be faulty.
I'm chasing Baxi for a solution but would welcome any suggestion as to what is causing the PCB to fail. On each occasion the PCB has an orange LED which indicates that it is satisfied and does not need to do anything. Basically the PCB is not resetting and allowing a call form either room stat or cylinder stat to activate.

 

[gazthepottertonengineer]

personally i would say the fault was elsewhere as these pcbs are very reliable

 

[mitch2000]

Well PCB No 5 is now in. A couple of resistors and capacitors are different so may be a different batch.

What else could be causing the fault?

 

[croydoncorgi]

I'd have thought the first thing to look for would be damaged wiring causing a short to earth.

 

[mitch2000]

corgigazza has mentioned something about a mains filter for a Baxi 50 HE model. Is this a standard part than could possibly be fitted to mine?

If it's damaged wiring surely Heateam should be able to do an electrical test.

 

[mitch2000]

PCB No5 has failed today. Got an Orange light but nothing is happening.
PCB No6 now fitted and system running again.

This is now totally unacceptable. In the past month I have had 6 PCB's and heating for only 12 days out of 31.

I'm desperate for a solution and any ideas would be welcome.
Tomorrow I have Baxi's Heateam engineers coming out but I would like any suggestion from you guys to put forward to them tomorrow.

 

[Agile]

I am sure that it would be quite easy for an engineer to find the fault!

Unfortunately many of the staff engineers working for those firms tend to be more "parts changers" rather than true "engineers" with diagnostic skills.

I suggest that you should be relaxed as its their problem and its up to them to send someone competent to fix it.

Perhaps when its on PCB 50 they might send someone who knows what he is doing?

I am sorry that I am too far away to help you as it always interests me when they get it so wrong.

Tony

 

[mitch2000]

Agile, I would welcome any Ideas.

 

[corgiman]

wow tony so you accept the bbu's do have pcb's then??

just pulling your chain mate

 

[mitch2000]

boliers working at the moment and Heateam have been out again. Engineer opened up the PCB case, Tested electrical feed / switched live etc.. which was OK. Talked a lot of common sense but still couldn't diagnose a problem. Engineer took away three faulty boards and said he would get them tested.

I've now been on to Baxi's customer relations, who are hard to get hold of to say the least. They have looked into the details and given me two options:
1. Wait for the test result of the failed PCB's.
or
2. Replace the boiler completely with another new one, but if the PCB fails again then they say it won't be covered on the guarantee as there must be a fault not associated with boiler.

I'm reluctant to accept either offer. I think 1 is the best option and 2 sounds like their trying to pull a fast one!

I feel like I am stuck with this boiler as I don't believe you can get another make of Back Boiler.

 

[Soggy_weetabix]

Baxi potterton deliver poor quality appliances and poor customer service.

Expect continuious calls to fix their badly designed boilers, and muppets who know nothing apart from changing a PCB.

Has earth leakage been elimenated?

David

 

[mitch2000]

It's now had two more PCB between Friday and Today. I think that's 8 in total. I've had a qualified electrician to check the supply circuit and that's fine.
As far as I'm concerned Baxi can have it back!

 

[ChrisR]

Thought I'd look at the Manufacturer's Instructions. Couldn't find it for a while - its a variant of the Bermuda Inset 3

Just a thought - have they changed the pot switch and leads?

That sort of thing could be intermittent and affected by heat

 

[mitch2000]

Yes Chris,
Its had at least three of them I think, along with heat sensors. On the seond breakdown Heateam replaced a complete burner tray assembly and it lasted from Saturday to Friday (nearly 6 days).
The PCB keeps failing with the same fault (Orange LED), which I believe means its calling for heat/ignition and needs to fire up.

 

[ChrisR]

Well good, it should have done by now!
Judging by the cost of the board there can't be much on it; some of use would be probing about to see how far the volts go..

It might - just - be to do with the electrical supply the boiler's getting. If the fused spur (what have you got?) being used is a bit intermittent due to a poor contact or fuse, the power could get interrupted. That would deprive the pcb of its permanent live connection, pump could then send a spike or voltage cos it's still turning back up to the Switched live input, which it isn't designed to handle without mains on the permanent live. I've seen it happen and blow electronics, but not on a boiler yet.

Has anyone suspected the pump? It shouldn't cause problems as far as I can see, as it isn't supplied off the board, but some effect along the lines of the above could be possible. That's clutching at straws, but SOMETHING bonkers, and possibly not withing the boiler, is doing it.

Have they checked the earth continuity back to the consumer unit? Earth loop test from the chassis would be good. You could be getting HT fed back through commoned wires which are supposed to go to earth but don't (very well), to a sensitive bit of electronics.

Nice to have an interesting problem at someone else's expense. It'll be sooo boring when you find it!