worcester bosh 28i no ignition

[Deleted member 32524]

Hi there,

looking for some help. working on a bosh 28i junior greenstar. not igniting. got a spark but no ignition. gas valve, maybe? got current going to it but does not open on p1 when trying to ignite. maybe air pressure switch?

Fan, pump running.

Thanks,

Duncan

 

[AlexGas]

Check the gas valve solenoid.

 

[dancinplumba]

wrong forum, try the private ga safe forum

 

[Deleted member 32524]

thanks alex did not think of that.

cheers dancin. will try there.

 

[AlexGas]

My bad! It needs to be moved, please.

 

[PlumbBobBob]

will do

 

[AlexGas]

Thanks, Steve.

 

[vern]

Hi there,

looking for some help. working on a bosh 28i junior greenstar. not igniting. got a spark but no ignition. gas valve, maybe? got current going to it but does not open on p1 when trying to ignite. maybe air pressure switch?

Fan, pump running.

Thanks,

Duncan

Greenstar don't use APS for fan, it's done by the fan PCB tachometer, condensing or SE.?

 

[Deleted member 32524]

condencing. no aps?! ok thanks. i have only had a quick look thought i saw it up the back. I take it that must monitor the flue then.

 

[vern]

condencing. no aps?! ok thanks. i have only had a quick look thought i saw it up the back. I take it that must monitor the flue then.

Top left back there is an APS yes, monitors for flue blockage, wired in series with overheat and flue stat.

what gas valve is on it sit or prettle? Either way put manometer on inlet see if it drops on ignition, if it drops and probes are ok zero governor is crackered, if no drop one of solenoids faulty..... To test spark turn off gas remove probes sit them on heat ex and create demand, you should see a good strong spark!

 

[Deleted member 32524]

there is no drop on gas valve during the sequence. locked gas off and tried it with u gauge on inlet. I took the leads off and sparked them on my scredriver, would i need to take the assembly out? the spark might have looked a little weak.

no idea what gas valve it is. I think it is original.

 

[arran197]

They have an aps. Not known one play up though tbh. One of the only boiler I know of that still uses an APS. They call it a flue pressure switch though and it's located at the top left of the boiler. But if it's sparking, then chances are it's the gas valve. Check the resistance of the 2 wires that come off each of the 2 solenoids at the multi pin block connecting to the pcb, you should get ~ 180ohms on one and 360ohms on the other. If you have OL or strange figures it'll be that.

 

[Deleted member 32524]

Thanks Arran. Can i change the solenoid/s or is a new valve?

 

[arran197]

No, new valve. They're common for going and is now a different valve. You have to change a few other bits with it too, but it's all included in the kit. It's not too difficult to do, but the screws holding the valve in are a little awkward. I've changed about 10 now. And about the same with fans. Seem to last about 5 years and expire!!!!!

 

[vern]

Thanks Arran. Can i change the solenoid/s or is a new valve?

If solenoids on the front it's a sit, straight swap....if solonoids on rear prettle valve, all bits in kit to swap over then set up Co2

 

[Deleted member 32524]

god advice. Thank you all for your help. it is the one with the purple wires coming off the back. i really appreciate the help. thanks guys.

 

[vern]

god advice. Thank you all for your help. it is the one with the purple wires coming off the back. i really appreciate the help. thanks guys.

Prettle then junk valve and outlet hose, fit sit valve just swap outlet pipe to new valve with hose with o ring, comes in kit! Set up high and low co2 9.8% & 9.2%

 

[herp_lee]

Top left back there is an APS yes, monitors for flue blockage, wired in series with overheat and flue stat.

what gas valve is on it sit or prettle? Either way put manometer on inlet see if it drops on ignition, if it drops and probes are ok zero governor is crackered, if no drop one of solenoids faulty..... To test spark turn off gas remove probes sit them on heat ex and create demand, you should see a good strong spark!

Hi Vern i had this couple of weeks ago on a worcester. I put my manometer on he working pressure nipple and it dropped to zero when it tried to ignite. Is that what you are refering to? Nice info if it is.