Toyotomi om 180 random shutdowns

volvoman

My OM 180 sometimes will shut down before the fan reaches full speed. The thermomistors have been changed, air pressure switch changed, burner cleaned, flame sensor cleaned, nozzle changed, fuel delivery checked. The dealer can't isolate the problem and his solution is a new OM 128. It serves as house heat and hot water. The problem started after an air mover replacement(leaky coil) and water heater service. An air eliminator was placed in a tee on the relief valve side. On successful light off, two quick clicks can be heard from the unit, when it fails, one click is heard them a click a few seconds later that coincides with the trouble light coming on. do I need a new heater or is it a problem that can be fixed. Thanks

Fishingfool

Has the lamp circuit board been replaced? There are two types of amber warning light. The 3 second light and a 25 second warning light. The 3 second light is in relationship with the safety control circuit and the 25 in relationship with the photo eye seeing the light when the burner is lit. With the 3 second light I would first pull the burner and make sure the electrodes are properly set. Test it by placing the burner on top of the OM-180 at an angle leaning against the air intake throat. Then plug in the Q clip (white wires), the H clip which is the yellow wires and the G clip which is the gray wires, do not plug in the blue wires to the fuel pump. Next fire the unit and the spark coming off of the electrodes should be a maroon color in a shape of a flickering tongue. If the electrodes are too far apart then the Arc will have a blue color or be jumping off to the burner head. This is the only way to check the electrode’s setting to make sure they are properly set. Next step if the OM-180 still wants to give you a amber light then replace the lamp circuit board. Toyotomi part number 20476467. The fuel pump pressure need to be at 192 PSI. Hope this helps you out.