Need a pointer any Vaillant Engines

[Deleted member 64964]

Hi Guys/Gals

Top was supposed to say Any Vaillant Engineers that could shine a light please.

I have been called to a Vaillant TurboMax Plus 828e

Fault is while running in hot water mode or heating but more so in full rate/DHW, it fires up and runs but the flame drops as if its running out of gas a bit and starts to spark again as it loses proving eventually in secs not mins it shows an F29 and locks out.

In order to stop it doing this I lowered the burner pressure to 6mb ish and it wont do it, if you take it above this to the 10.8mb it should be it faults the higher you try to take it the worse it gets and the less time it will run.

I have changed the PCB as Vaillant Tech said it would be that.
I have put a new Gas Valve on it.
I have had the regulator changed on the meter.
It has had a new electrode on it but not by me, its proving anyways otherwise it would fault all the time surely and not just when BP is low

So please anyone could you advise what the hell is going on with it lol

Thanks in advance.

 

[Rabbitman]

Hi thermo,
in relation to the above post f29 is usually a straight forward fault to fix (ie appliance failing to rectify) although the bit in the middle if ive read correctly about lowering the bp makes it work does confuss me slightly, but i would try this

1 inlet working which seems like im patronising you (sorry)

2 remove the burner and give it a good clean with a small wire brush, at the same time the injectors can be checked ( I find a paper clip is good )

3 if the pcb has been changed then the little jumper plug on the LHS should be set depending on the gas valve fitted ie pins 1&2 for Honeywell and 2&3 for SIT as if incorrectly set will bugger up your ignition settings

4 then check the electrode as ive had it loads of times mainly BG where they fitted the part then removed if the fault still persist ( if it a metal one then replace )

4 then either remove a wire from the or lock into P2 and set the min bp to about 3mb, then do the high normally about 10mb bearing in mind that the two valves adjust differently, and hopefully that's it.......... Although some turbos not all, had a LWPS fitted just above the pump designed to interrupt the gas valve but it's unlikely to be that

 

[Deleted member 64964]

Thanks Rabbitman,

I understand your covering all bases

Working pressure is spot on had a reg change and the meter is behind it on the outside wall with a solid 21mb

I will however pull the burner out and give it a good clean with the injectors. It's apparently been regularly serviced (not by me) and did look clean in there so didn't go any further.

This is what confuses me as I have it running on p2 3mb and p1 6mb but can't get it anywhere near 10mb.

I put the old pcb back on it in the end.

Interesting point about the pins for sit and honeywell I will check that out as it's has new parts before I will check that too.

It's got the plastic electrode on it so should be ok.

LWPS interesting too.

Thanks really helpful post appreciated.

 

[buckley plumb]

I had one with similar problem but that was scale in gas pipe blocking gas valve and burner

 

[Rabbitman]

Hi thermo,
just had a thought in relation to the fault (it never dawned on me last night) have you tried running the boiler at full rate with the combustion cover removed this is a two minute test and if the burner holds then your looking combustion......... I had blocked fins on the main hex/flue issues cause similar problems

 

[AlexGas]

Could be a dodgy earth.

 

[Deleted member 64964]

Hi thermo,
just had a thought in relation to the fault (it never dawned on me last night) have you tried running the boiler at full rate with the combustion cover removed this is a two minute test and if the burner holds then your looking combustion......... I had blocked fins on the main hex/flue issues cause similar problems

That's an interesting point! Thanks

It just work properly with the case off bit I don't think I increased the burner pressure to its correct setting or had it full rate.

when I spoke to tech they said it's getting full combustion when the case is off bla bla bla. It's either a gas valve or a pcb so I didn't go any further with it.

Thanks for that again!

 

[Deleted member 64964]

Could be a dodgy earth.

Checked all that, but thanks for the input.

 

[Leo21]

Have you got flame lift? If it's running ok on low bp it points gases mixing. Corroded flue or rotten internal flue clip.

 

[Rabbitman]

Hi thermo,

just out out of interest did you sort that f29,

 

[Deleted member 64964]

Hi thermo,

just out out of interest did you sort that f29,

Hello Mate,

They are being a bit unavailable at the min. They said it's working brilliantly now I've sorted it. It's only running at 6.5mb

I will get back there at some point. the landlord is a friend so I will have a word with him if they don't sort it out lol