Water heater in 173t

Hi Dan

You must have water in the H/W tank, I assume you do. If you turn on the water pump, and go outside to the W/H and just barely open the emergency pressure release valve (just like your home W/H) water should come out. You would now be positive there is water in it.  As far as making H/W on propane, I recommend this. You go out back and open the cover. Have someone turn on the H/W switch inside (do not use the outside switch, make sure its off) Do not get your face to close, and listen. You should hear a series of clicks. The system tries to lite the fire 3 times before shutting it down and showing DSI fault inside. You should hear those three sets of clicks if it doesn't light. You should smell propane at this point (if it doesn't light).  If it does light, you will hear the "Whoosh" of the ignition (Why you should keep face away). If you make several attempts and it only does the clicks, and doesn't light, I would suspect the igniter board. Your local dealer should be able to check it, mine has a tester, I assume they all do. It's a cheap part, 85.00 on amazon, maybe 120.00 at the dealer. It is probably located right on the hot water tank. It should be rather cheaply attached with a wire tie. Mine is in a small white box about 3 inch long, 1 1/2 inch wide. Good luck and let us know what happens