I have a hybrid heat pump with a gas furnace built in. Model R4GC-042K072X, made by Nordyne//Frigidaire. It is set up for natural gas, and I need to convert it to propane. It has #72 nozzles now for the natural gas, what size is needed for propane? It has a Honeywell manifold VR8205M2443. How is the manifold re-set for propane? I see the screw cover with a black plastic screw adjuster under it.