Install the app
How to install the app on iOS

Follow along with the video below to see how to install our site as a web app on your home screen.

Note: This feature may not be available in some browsers.

Welcome to the forum. Although you can post in any forum, the USA forum is here in case of local regs or laws

Jun 13, 2021
7
4
3
Coventry
Member Type
Heating Engineer (Has GSR)
Hi anyone. I have the F28 code on this unit. Gas IN is fine and on start up fires but within a second or two, the gas valve shuts. Taken the valve apart and the diaphram is ok,no splits.
S code runs thru 1, 2 & 3 but will not progress to 4( burner ignited). Checked the low voltage solenoid and getting 35 V1 & 17.8 V2(53 Ohms across 2 outer pins). Vaillant say in their opinion it is the pcb but having changed it, the problem remains. The fan gives 418-420 rpm reducing to 380, again vaillant say this ok for initial start and within 10% range.
I've also changed the sparker & ioniser and had the burner out,inspected & cleaned. The 2 connections to gas valve give me 21.8v reducing to 15 then zero, now. Could this gas valve in fact be faulty, even tho the solenoid readings say otherwise?
continuity runs thru all connections and earth is good!
Anyone know where to look next, other than blind replacement?
I have a noodle, and it's being Baked!

Thanks for any help.

PS.. only just registered so not allowed at this point to access the gsr private advise forum.
 
Last edited:
Sorry Virgo, it appears you’ll need to wait, you’ve just discussed a lot on an open to public forum, of gas components - site rules. How old is the Vaillant? Any other gas appliances? If you’re desperate, try diynot.com, approval is usually pretty quick.
 
Sorry Virgo, it appears you’ll need to wait, you’ve just discussed a lot on an open to public forum, of gas components - site rules. How old is the Vaillant? Any other gas appliances? If you’re desperate, try diynot.com, approval is usually pretty quick.
ok, i see. thanks for replying. Shame i wasn't informed a bit earlier by someone/anyone. I would have removed it, or moderators could have?. I've just read the reason why i must wait, not sure i get why an engineer can't access the engineers part, without posting a 100 or more posts first!
defeats the object of helping each other.

cheers anyway.
 
  • Like
Reactions: Aquarius
ok, i see. thanks for replying. Shame i wasn't informed a bit earlier by someone/anyone. I would have removed it, or moderators could have?. I've just read the reason why i must wait, not sure i get why an engineer can't access the engineers part, without posting a 100 or more posts first!
defeats the object of helping each other.

cheers anyway.
As I said try diynot.com, zero post count for privileges of gas side, plus some vaillant engineers dip in time to time.
 
appreciate that mate.cheers.
I did email a Lou, with my gsr#, few days ago now.
Boiler is owned by my good friends, so they won't pay for my time. But i will try one more thing, before i put a Baxi in!
much less grief.
All the best Aquarius.
cheers.
 
  • Like
Reactions: Aquarius

Official Sponsors of Plumbers Talk

Similar plumbing topics

We recommend City Plumbing Supplies, BES, and Plumbing Superstore for all plumbing supplies.