I have been having gobs of problems with southbend equipment. Most of the problems deal with non ignition on GS and GB series convection ovens. We go out and it is working then we get another call next week. We replace ignition board, HSI and flame sensor then down again. I think southbend has wire warness problems, but they will not admit that. It could be ignition module problems.
On the 3 I personally looked at recently, flame sense current was above 1 microamp. I always push all contact plugs togather.
I had a STRG-5G steamer last year, Gas valve voltage dropped out then came back. This steamer had a new gas valve, module, ignitor and flame senser. I also increased gas pressure. We lost this account over this steamer. (Hate not easily being able to see the flame on this steamer.)
I have a BGLM-40 tilt skillet that is running away. We just changed the thermocouple assembly, highlimit and thermostat board.
Anybody have any help they can offer me. Can't keep changing parts on these things. Southbend is pretty proud of their parts
If the superheat ain't right it ain't charged right.
Replace the module with the new style fenwall module has worked well for me.
In my experience, most units with hsi's don't have flame sensors. The safety is accomplished by measuring the amp draw of the hsi. Try checking the voltage of the transformer. If the voltage drops too much you'll get intermittent ignition failure.
Also check for cracked solder on the ignition module
Units built in 2011 did have a rash of cold (cracked) solder joints on the ignition board big plug pins. If you took the board out of the case, you could actually see them.
A frequent problem I see with southbend convections is the inshot burners not lighting across to hit the flame sensor. This was such an issue that they redesigned the burner in 2011. The flame sensor changed from the little thin one with the bend to a straight thick one. They also improved the gas passages between the burners. I've had to pull out a lot of burners and blow them out with co2, especially the passages between the burners. Should all be around an 1/8-1/16" between the burner shots. The symptom will be you'll hear it light and drop out, repeat, repeat, then you in lockout. You can hear the right burner light but you'll also smell gas from the rest not lighting.
And remember, when you take the burner cover off, your DRASTICALLY changing the burner air flow.
Also, the blower wheel can't have any debris in it. Southbend swears that you have to pull it and wash it regularly. That the burner air inducing relies on the blower wheel air flow. I refuse to clean or replace blower wheels because of their crappy burner design.
Ovens and ranges are about the only southbend I have the pain of working on. Sorry I can't help on the rest.