LP conversion and orifice spud change

What is going on

To run this furnace on propane, the gas valve has to be converted by replacing the regulator springs with the kit springs, and the orifice spuds changed as well. Order the correct LP kit from the manufacturer. Conversion must be done by a qualified installer, service agency or gas supplier, because a wrong conversion is a real fire and carbon monoxide hazard. Take care to shut off the gas first, and leak-check every joint when you are done.

Likely causes

• Furnace installed on a property with propane instead of natural gas
• Elevation changes that need different orifice spuds
• Swapping fuel after a tank install
• Replacement parts that arrive set for the wrong gas

Check in this order

1. Shut off the manual main gas valve and the electrical supply before starting
2. Replace the pressure regulator springs with the LP kit springs
3. Remove the gas manifold
4. Replace the orifice spuds
5. Reassemble in reverse order
6. Turn gas on and check operation and manifold pressure
7. Leak-check all joints with an approved detector
8. Attach the notice label stating the furnace has been converted to LP gas

More furnace guides

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• Blower does not start after burners light
• Burners go out before the heat call ends / short cycling
• Canada only: derate high altitude by lowering manifold pressure
• Cement PVC vent joints