Ignition failure at peak times!

[symboliser]

Have a Vaillant Ecotec 831, less than 3 years old, serviced annually, with magnatec filter. In last week boiler fails to ignite (ignition failure) , code 28, but mainly between 6pm and 8am ?? It "explodes" inside and then fails. Behaves normally during the day. Gas work was done on our stree at end of last summer... of course anyone coming out to check gas pressure or boiler in the day will see nothing wrong! What do you suggest for me to investigate? I am just the boiler / home owner, not a plumber or gas man...

Thanks in advance for your opinions and suggestions.

 

[FlyingFish]

It might be worth getting your gas man out to do a working pressure test at the boiler, and the meter. The thing is, that if there is a pressure loss across the pipework, then that's an installer issue, and if the installer is the same chap you use for servicing, he may not be willing to admit to that!

This can be awkward, but it might be worth calling National Grid out during these 'peak' times saying you have low pressure. Once the call is made, they come out straight away normally within 4 hours. If you have a gas cooker or hob, then it's easy to mention that you might have seen the flames looking '
low'.

Mick

 

[symboliser]

Mick, thanks for the quick response. It is a very frustrating situation. We don't use the same person that installed the system to service it so we're ok there. It has been fine the entire 3 years we've had it (service due in a few weeks). We don't have gas hobs, but do have gas grill and oven. It is very difficult to tell if gas is "low" from the oven and grill. Would be a lot easier if we had hobs. Saying that, when the combi boiler was installed the gas pipes used to feed the preexisting boiler (open system) and oven was not used as the Vaillant needed bigger pipes, so they were installed and routed to the boiler from outside the property rather than rip up floors and the kitchen.

I am curious about the work the grid did in August now though... they did the whole street...

Vaillant won't send someone out under warranty until at least Monday and threaten charging a £90 if they find its a supply issue rather than boiler issue.

 

[FlyingFish]

If a service is due, then that's a great opportunity to get your guy to measure and record the gas pressures for you. It could be that things have changed and it's now on the lowest allowed limit or just below, which would be ideal to call national grid out. Your boiler should to a certain extent work adequately with the pressure at the low end, but go too much beyond and you'll get flame detection errors. I wouldn't call vaillant unless your service man recommends it.

Mick

 

[symboliser]

Thanks again, Mick. Good advice. Shame there's no easy way (for me) to measure the pressure. I would love to be able to just take readings and record them over time to use as proof there is a problem at my property (assuming that's the issue, which it may not be).

 

[symboliser]

Had mains tested by National Grid callout. Engineer saw the fault but was happy that gas pressure to property is ok, so must be something else... Waiting to see if the HomeServe chaps come tomorrow to investigate boiler + pipework.

 

[Steelmasons]

, code 28, but mainly between 6pm and 8am ?? It "explodes" inside and then fails. Behaves normally during the day.

It won't have anything to do with working pressure , the fault lies within the boiler.
Eventually the boiler will fail to reset.

 

[symboliser]

Thanks. Sounds like you have experience with the diagnosis. Is there a reasonable explanation as to why the fault has not been occurring during the day but only in the evening & overnight?

 

[AGAS]

symboliser do yourself a favour and get vaillant out , of course vaillant will charge if it has nothing to do with their boiler .

 

[oldbuffer]

Had same problem, same boiler, about 2 years old. Turned out to be the meter regulator. Once changed boiler was fine again. Cost nothing, and saved Vaillant call out fee.

 

[symboliser]

Very useful tip, thanks! Grid engineer tested pressure to property as 20mb, but that's all they'll test when called out by National Grid. My gas box has two feeds from it (an old one that now only feeds the oven and new one that routes around the outside of the house to the combi). We'll see what the chaps sent out by home cover say tonight and if they can't work it out I'll get hold of a local chap to have a look.

 

[Agile]

Did they measure the 20 mbar with the boiler operating?

The traditional teaching is to measure it with three gas hob rings on. But that's a little old fashioned now and if followed can not show up serious loss of pressure when a 30 kW boiler is turned on!

Tony

 

[symboliser]

Valid point. When the chap was round the fault was on. When starting up the boiler the scary internal explosions were heard but after a few attempts got it started up. As it's a combi and I have no gas hobs he just let hot water run and measured pressure going into the box at the front of the property (which I suppose is the Grid's demarcation point) and it still measured 20mb.

 

[Agile]

Odd.

Normally they would measure it at the OUTLET of the meter where there is a test point already fitted.

Questionable where the required pressure of 21 mbar +/- 2 mbar should be measured!

Most RGIs expect it at the outlet of the meter!

 

[Dan Robinson]

Odd.

Normally they would measure it at the OUTLET of the meter where there is a test point already fitted.

Questionable where the required pressure of 21 mbar +/- 2 mbar should be measured!

Most RGIs expect it at the outlet of the meter!

Seriously?