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bud01234 · 11-23-2015, 09:42 AM

'98 national dolphin 5360 GM gaser just bought fairly recently. Tried out furnace for first time last night but when selecting 'furnace' from thermostat, it starts blowing cold air but never heats up. I tried using generator and shore power but no difference.

The stovetop burners work fine and I'm showing 3/4 tank of LP. I've read here that it may be the sail switch or a circuit board so may have to take it to repair center.... however, there is an info-sheet posted to the inside of a closet door that lists all the equipment on the unit and states very clearly that I have two furnaces. One is the front Hydroflame 85-35-11 and then a rear Hydroflame 85-20-11.

All this leads to my question (finally!) If there are two furnaces, could I switch to another zone to see if the other furnace would work? I think it's on zone 1 now but I can't get it to switch to zone 2 from the thermostat zone button.

Thanks!
Bud

Rook · 11-23-2015, 10:32 AM

Bud, you can easily verify that you have two furnaces by checking on each side of the coach for the presence of a furnace.....on the passenger side about half way back, driver side about the same place (I have two) If you cannot switch zones, that could be a bad thermostat or wiring problems. Pull the cover on the furnace that runs and have someone turn it on while you listen for a "spark snap" from the igniter.....if you don't hear one, it could be a bad ckt. board. They are easy to replace. Here is a video that could help. Rook

https://www.youtube.com/watch?v=d7YTOcSPOyI

JJH3rd · 11-23-2015, 10:36 AM

If (& I think you do have) the basement HVAC, is is a heat pump, BUT, when the inside temp is below a certain point, the LP gas heater comes on first to warm up the space so that the heat pump is effective. You can control this to a degree by selecting "gas" heat - which is only the LP furnace, as opposed to electric (which is the heat pump).

legryz · 11-23-2015, 06:43 PM

Don't think the basement HVAC units came out until 04/05 and went away in the last year of National. bud01234 coach is a "98" so he probably doesn't have basement HVAC.

Richard S. · 11-24-2015, 06:58 AM

If you google Hydroflame there is a lot of troubleshooting information available.

sirpurrcival · 11-27-2015, 02:07 AM

I have a 99 Tropical, you have a 36' Dolphin, I would be pretty sure you have 2 furnaces. I have one on the bathroom side with vents under the bathroom sink. I have a 2nd on the fridge side with vents close to the entry door and so on. You have a 4 button dometic thermostat/controller. To switch from on zone to the other, you hit the top two buttons simultaneously. You should see a zone number at the bottom of the LED readout. No heat pumps. Just Fan, AC (Cool), Heat. You more than likely have a Direct Spark Ignition model of heater so if all is well, you should hear some clicking noises when you try to run it. That is the spark trying to ignite the pilot. You probably have an appliance list somewhere in your coach (check behind cupboard doors). It will list the number and type of appliances including your furnace(s).