Quoted from Gerald Farris

If the "preheat" and "coach heat" switches are both turned on at the same time, most of the heat that is transferred from the water heater to the Hurricane fluid will be transferred to the engine coolant, so you will receive little to no heat in the coach.

Gerald    

Gerald--
As you have read in this thread, my Patriot Thunder model in 2000 had only a single switch marked preheat so it probably incorporated both functions.  So when I tried to use the Seaward electric heater to heat the coach, I assumed that whatever heat was being transferred to the Hurricane fluid was most likely ending up in the engine coolant.  You have now confirmed my assumption.  thanks,
Joel

Gerald,
  many thanks for a very concise summary of all my diatribes.   One question I havent been able to answer is where does the heat for the basement heating duct come from?  Is it from the radiator fan mounted in the coach furniture behind the co pilot seat?  If so we can keep the basement warm when operating the Hurricane 's water pump (Coach heat) and heating the water with the Seaward electric water heater.
You have answered my  question re "Preheat" on my Marquis switching on a circulating pump in the engine space.   Thanks again,   Happy New Year ,  jeremy

Jeremy,
The heat for the basement on your coach (2000 Marquis) comes from a heat exchanger and fan assembly that is located in the area between the top of your holding tanks and the floor of the coach. It is controlled by a small non-adjustable thermostat that is usually clipped to on of the fresh water lines that run above the holding tanks.

Gerald

There are two pumps in the hurricane bay on my coach what is the second for?

Hi Tom,
   I have two pumps in my Hurricane Bay as well.   Could it be that the other pump( much bigger)  is the one that is activated when the Hurricane Furnace is switched on??
This would mean the "coach heat" pump only works when you activate the "coach heat " switch.  A supplementary pump for those cooler evenings when you dont need the furnace, thus saving the furnace pump hours!!!!!  
  Gerald please help !!!

[quote=235]With the system that Jeremy has on a 2000 Marquis, there are two circulation pumps. The switch that is marked "coach heat", only turns on the Hurricane circulation pump to pump fluid through the water heater, the engine coolant to Hurricane heat exchanger, and the heat exchangers inside the coach. The switch marked "preheat" turns on the pump that circulates the engine coolant through the engine coolant to Hurricane fluid heat exchanger. The "preheat" pump is not needed if the engine is running since the engine water pump will serve this purpose.

This should answer your question. If not let me know.

Gerald

Hi Gerald,
  I am to assume the larger  pump in the Hurricane bay is the one that is activated by the "preheat" switch ?

Ok, my pump does not come on when I engage the coach heat switch now what?  The hurricane works great when engaged for heat is there.a fuse or relay on this switch?

Tom,
Check the wiring to see if you have 12 volts at the pump ;if yes, then the pump is bad. Apparently  these pumps have a 1500 hour life.

The waternpump works when the heater is on just fine just not on coach heat.  I have replaced the circuit board last year so there should be no issues there.

Tom,
  the switch could be faulty.......check to see if this is as simple a problem as the spade connectors either falling off or not being crimped tight enough. I have had a few connectors that were loose.  
My switch panel has an access board beside the pilot seat;a bit awkward to get off but doable.
I am looking for fuses for the Hurricane system pumps....no luck yet except for the ones on the circuit board inside the box.