Vaillant 838 operations

[5544]

Fitted a Vaillant 838 Eco Tech plus combination boiler to a property 6 weeks ago. all fine.
Customer called in to say that the boiler had locked out on F54 and F28. Reset did it again a few hours later, then been fine since.
I attended today to check a few thing:-
1. Gas pressure at the meter on Max was 20.5mbars
2. Gas pressure at meter on min was 22.5mbars
3. gas rate calculated at meter was bang on 38.5kw
4. pressure on max at the boiler was 13mbar. Working at the test point at the side/top of the gas valve. the book states that the operating band is 13 to 22mbars.

The pipe run is in 22mm to the boiler is minimal, no more than 6mtrs

I was a little surprised that the pressure at the valve was 13mbars since the gas rate was a little over allowing for errors.

if this becomes an issue ( this is the only time it has done it) I can imagine Vaillant are going to say to increase the pipe size?

Apart from a drop in supply pressure from the supplier has anyone else experienced this?

Since it is a Sunday morning please be nice.

 

[Scott_D]

Cut in a test point under the boiler for an accurate reading

Shake stuck in the gas valve maybe

 

[king of pipes]

I think Scott means shale often there can be some debris in the gas supply worth checking , always cut a a test point in before the gas valve and 38 kw always a 28mm supply . Kop

 

[5544]

THANKS FOR THE ADVICE. i did it at 22mm since it was such a small run, but if it plays up again ill run it in 28mm.

in all honesty i forgot to do the external test point. I normally now fit the Vogue boilers which have them in the valve itself which is much better.
thanks for the reply