Testing a gas valve on a Worcester Bosch & setting it up in service mode

DISCLAIMER:
This video is only intended for use by qualified Gas Safe Registered engineers. You must not attempt any work on your boiler if you are not qualified. You must always carry out 26.9 checks upon completion of works on a boiler.
~
I was originally sent here to change the gas valve, but it's always good to test the components before replacing as it can save your customer a costly repair.
With the power OFF and set your multimeter to resistance (Ω) you should be looking for the following readings on the top and bottom solenoids of the gas valve to confirm its good:
Top: 342 - 418Ω
Bottom: 171 - 219Ω
You can also confirm the ignition leads are good by checking the resistance on them which should be 2.1kΩ
Finally the voltage at each of leads to the gas valve from the PCB should be 35V DC.
The final part of the video shows how to get the boiler into service mode and setting up the gas valve for your max and min readings for combustion analysis.

[@MikeSmith-tx2lp]

Excellent diagnostic process, instead of the Christmas tree lights approach favoured by some ‘skilled engineers’. Thank you for publishing the expected ohms readings for good parts. Thank you.

[@cputilitysolutions]

Thanks for the comments mate 👍🏽 glad you found it helpful

[@Carl-re6zb]

Thanks for the solenoid ohms values bro...
One thing I acknowledged from working on Worcester Greestars is, gas valve and pcbs are pretty bulletproof...
Thanks for taking the time to post👍

[@yensabi]

Nice one , sometimes it’s worth checking other things to be sure especially with the high cost of a new valve.....👍

[@jonathanwilliams8309]

Another useful video, thanks.

[@saltnvinni1]

Excellent videos!

[@hamzaparvais3948]

Simple things fantastic bro

[@charlieb8582]

Really good video pal ! Keep the videos coming

[@cputilitysolutions]

Thank you mate!

[@xclusive463]

Got same Allen keys wera love them 🔥

[@stephenbryan8671]

Another informative video, how do you remember all the resistance values?

[@GasmanChris5705]

Top vid mate 👍

[@cputilitysolutions]

Cheers mate

[@stephenbryan8671]

Another informative video, how do you remember all the different resistance values? Not all way referenced in the MI’s

[@cputilitysolutions]

Thanks mate, I tend to remember the most important figures where I deal with them almost daily, however I have a folder with reference material I got from boiler manufacturers courses, etc as well as can't always remember everything off the top of my head

[@GreenNgold7]

Sounds like you work for a housing association too😂 gotta love getting parts that other people have ordered for you

[@cputilitysolutions]

Always mate 🤦🏽‍♂️

[@pspr33]

I've been recently getting locking faults on our Greenstar 4000 (fault 2949) and it's gotten to the point now where the call for hot water won't fire but the CH is working fine. Could this be down to the valve not being set correctly? It's had this locking fault pretty much since we had it but very intermittently. Thanks for any help.

[@krcright9746]

If the gas valve was at fault and closed. not allowing gas through.. am i right in saying the igniter won't even try to start / spark ?

[@deakgolf20]

Hi buddy. Just a question about the test figures. Do you keep notes (mentally or physically) on the ohms readings etc or is there a platform or database that you use? Keen to know as I end up calling manufacturers every time for the data. So if there was say an app or a website with such info then it'd be greatfully appreciated to know about ☺️ good work my man, enjoying your content.

[@cputilitysolutions]

Hello mate, I remember the common figures that I come across, but any others I make a note when I call up manufacturers and save them on my phone

[@deakgolf20]

Yep that's what I do. I'll carry on as I am then 😁

[@dec9044]

Do you know if this Worcester you’re currently working on in this video if you was to replace the gas valve does it come pre set ?

[@cputilitysolutions]

I believe you would have to check the readings and set it up

[@krcright9746]

I'm getting 388 ohm's on Top solenoid And 177 on Bottom solenoid.. is that within tolerance on a 28i greenstar with same gas valve I'm diagnosing ??

[@Carl-re6zb]

Sounds spot on for the sit sigma valve

[@mehmetaliciftci3495]

Hello, I'm following you from Turkey, can you turn on the Turkish subtitle feature?

[@viratpatel375]

Is it the same ohms reads on all worchester gas valves?

[@cputilitysolutions]

No, these readings correspond to this type of gas valve known as a Sit Sigma style with 2 connections. The other style is known as a Prettle valve which only has 1 connection 👍🏽

[@aryansx]

There is humming noise from air intake worcester boiler. Co2 ratio is out. This is the reason its making noise

[@muradkhan6787]

Very bad