38cxi pre-heat problem

[LenB]

Good evening all,
I am a new member, a retired engineer, but not a heating engineer.
I have a problem with my 38cxi with after burn at the end of the pre-heat cycle, that my Service Engineer has not experienced, and which Gow-Worm support do not appear to be able to advise on. I can tell when it happens because the boiler makes a significant rumble, like a lorry entering the kitchen! It appears to be more prevalent in the evening, and I think during the night, but I'm asleep then.
Has anyone experience of this problem, I can stop it happening by turning down the water temp, which naturally cancels pre-heat, but I like my water hot.
I do not intend to attempt anything personally, but assist my Service Engineer, if possible.

 

[Dogby]

I would get Glow-worm on the phone with engineer present and get mi spec for voltage and pressures seems like the mix may be wrong

 

[LenB]

I would get Glow-worm on the phone with engineer present and get mi spec for voltage and pressures seems like the mix may be wrong

We have already been down that route, Glowworm could not help

 

[LenB]

Thanks,
But we have already been down that route, Glowworm could not help.

 

[Chalked]

They probably couldn't help over the phone. They will be able to fix it, if you get them to call out.

 

[Dogby]

When you call d them did they give the specific pressures for the gas when on preheat and fan pressures etc or just talk through options? If just a talk through you can ask for more specifics as they have a much more detailed spec of settings on their database but only share when specifically asked