Hurricane Service

[Dick Simonis]

It's possible that the PT and the Marquis may have a sligtly differant arrangement.  Like Joel, I seem to only have the preheat switch on the console that serves both functions.  Never heard of the coach heat switch.

As I understand, once this function is selected the recirc pump runs in contiuous operation without regard for any thermostat settings.  If so, while handy, will require a pump replacement more often.  I believe the manual calls for a new pump every 1500 hours.

[Jeremy Parrett]

Hi Dick,
The Hurricane water pump runs when the living area thermostat is switched to "Gas heat " and the Hurricane is switched on. When using the electric water heater to heat the coach I have to switch the water pump on using the "coach heat" switch.
 Maybe Gerald can shed some light on this.  Pumps are cheap enough to replace considering.   My Hurricane has only 378 hours on it after 12 years of life . 1500 hours might take some time to reach !!
 If closing your "preheat" switch runs the Hurricane water pump then you can use the Seaward electric water heater to heat the Hurricane water and therefore heat the coach; assuming it has a heat exchanger.
I guess Beaver saved $$$$$ by running both functions off a single switch.
 My question is" what does the "preheat " switch on my coach actually do??  I know there is a heat exchanger beside the C12 .That is how the engine heats the Hurricane water and visa versa. The 2 valves back there to allow this to happen are manually opened. Maybe there is another pump back there to boost circulation?  

[Joel Weiss]

Hi Jeremy--

Thanks for the very clear explanation.  The issue seems to be that the Patriot Thunder has only a "preheat" switch and not the coach heat one.  When I push the preheat button it definitely does turn on the Hurricane's circulating pump.  I had always assumed that the purpose of that was to flow warm liquid through the engine.  But you are definitely correct that doing this will also flow liquid through the Seaward tank.  I had never thought of the reverse effect of the Seaward heating the flowing liquid.  I guess the only downside is that the circulating pump will run continuously regardless of the thermostat settings but, if not done all that often it probably won't add that many hours of pump usage.

Now I'm wondering if the two switches were consolidated into a single one on my MH.  Do you know what actually happens when you push the preheat button?  Is there a solenoid that opens or closes to send liquid through the engine?  I have used the preheat feature to keep the coach warm while traveling, but not often enough to convince myself that it truly is working.

Since we're going to have some cold weather tonight I'm going to push the "preheat" button to see if it works as you describe.  I don't intend to turn off the main Hurricane since I like being able to have unlimited hot water for showers.  However, if things work the way you describe the circulating liquid should stay warm enough to eliminate the need for the burner to be used for heating (or at least not as much).  The operating aquastat in the Hurricane is supposed to trigger the burner at 149F, so the ~120F water from the Seaward won't be sufficient to keep it from running at all, but it shouldn't have to raise the temp of the Hurricane fluid by more than ~60 degrees until it reaches the burner off temp of 185.  

I'll know more by tomorrow morning.
Joel

[Jeremy Parrett]

Hi Joel,
   Last night here it was 47 deg F and using the seaward electric heater to heat the Hurricane water we were able to maintain 64 degF in the coach.  Warm enough to sleep.
  There is a heat exchanger on the passenger side front end of the engine  behind the service bay. There is a pump in the engine coolant system which is activated by the "preheat" switch.
The Hurricane system either with the furnace running or by the Seaward electric water heater and Hurricane water pump(Coach heat) circulates hot coolant through this heat exchanger beside the C12. The engine coolant pump (activated by the "preheat" switch) circulates the engine coolant through the same heat exchanger and warms the engine. The two systems use different coolants and so this has to be the way it is set up.    When you activate your "preheat" you are switching both pumps on ,thus circulating the engine coolant and the Hurricane coolant.
   Now if we could rewrite the manual everyone else could easily see how this versatile system works !!!
   "Final answer".!!!!

[Phil N Barb Rodriguez]

Anxious to see your reply tomorrow Joel. While at the Bend Service a few years ago I was going over the coach dash board with Ken Carpenter. When I got to the "engine preheat" switch he said "that does absoutely nothing". I asked why it was there....he wasn't sure.

When I turn the switch on I don't hear anything happening. However, I've never gone to the back of the coach to see if the switch caused something to turn on because I expected if it did turn anything on it would be in the Hurricane compartment.

Good comments from Jeremy. Hope that there is not a big difference between the Thunder and Marq heating systems (Hurricane).

[Joel Weiss]

So here's what we found last night:

1.  The preheat switch clearly turns the Hurricane pump on; you can hear it running.

2.  After having the switch on for 2 hours we set a thermostat to call for heat without the Hurricane burner being on

3.  No heat was detectable at the registers (even though they should have been at least warm)

The only thing I can think of is that if the "preheat" and "coach heat" functions were combined into a single switch, then fluid circulates through the entire system including the engine heat exchanger and the Seaward tank when the switch is on.  Since the Seaward only has a ~1500 watt heating element, it might be capable of heating the circulating liquid to a decent temp but not if it has to heat the engine coolant as well.   So by combining the functions into a single switch the "coach heat" capability was lost.  

This would agree with my owner's manual which says nothing about heating the coach in this mode.  As poorly written as the manual is, it at least does mention "preheat".  So my assumption is that someone figured out that using the Seaward to heat the coach in this mode would not work.  This may be why the so-called Comfort Heat system was created which added an electric heater to the Hurricane.  I think Gerald knows something about this add-on.

[Jeremy Parrett]

Hi Joel,
   The radiators will feel very cool. This is normal ,as the effect called 'latent heat tranfer' makes your hands feel cold even though a minute amount of heat is coming from the radiator.  I doubt that the engine coolant will effect the system's ability to eventually heat the coach,but it will prolong the warm up period.  If you shut the valves at the rear that allow the hot engine coolant to warm the coach system you can improve things .  Try running the Hurricane to get things hot and then switch it off and let the Seaward electric water heater carry on from there.  last night was again 47 degF here and the electric water heater kept the coach at 64 deg F.    Great for sleeping.
What the "preheat" switch does on my coach must be one of three  things:
) it   opens a solenoid controlled valve set to allow engine coolant to flow through the heat exchanger
2) it starts a pump to circulate the engine coolant through the leat exchanger
3) both of the above.

[Joel Weiss]

Since the use of the Seaward as a coach heater puts additional hours on the pump (and I have ~1,400 hrs already) and I already own two small Vornado heaters, I'm not sure it really matters whether or not this works for me or not.  The Vornados are very quiet (a lot more quiet than the Hurricane fans) and do a better job of circulating the air.  If I set both in low power (750 watt) mode, they keep the coach warm with outside temps >40F.  Since I don't intend to be in places any colder than that, they give me a totally acceptable way to use electricity instead of diesel fuel to keep warm.  The only time this matters anyway is when we are parked for a couple of months during the winter. Normally, the Hurricane's fuel usage is inconsequential.

[Dick Simonis]

I'm betting the "coach heat" switch turns on an additonal AC heating element in the Hurricane box.  I seem to recall this feature was an option and more than likely it was part of the Marquis package.  I'm with Joel on the small electric heaters.  I have a hardwired baseboard heater and a portable that keep things toasty down to about 36 outside.

[Jeremy Parrett]

Hi Dick and Joel,
  I totally agree. We have 3  ceramic space heaters that keep us toasty warm down to 32 degF or below.  It has been a good exercise to finally discover how the Hurricane system can be used in conjunction with the other systems on our coach.  
There is no  coach heating element in the Hurricane box.  The "coach heat" switch turns on the Hurricane pump which then circulates the Hurricane water through the heat exchanger in the Seaward electric water heater tank ,thus heating it and warming our coach.  As this system uses the water pump(hours)  in the Hurricane system we will not use it unless the temps get really cold ,when  we  worry about freezing the basement which space heaters will not warm up.

[Joel Weiss]

Hi Dick and Joel,
  I totally agree. We have 3  ceramic space heaters that keep us toasty warm down to 32 degF or below.  It has been a good exercise to finally discover how the Hurricane system can be used in conjunction with the other systems on our coach.  
There is no  coach heating element in the Hurricane box.  The "coach heat" switch turns on the Hurricane pump which then circulates the Hurricane water through the heat exchanger in the Seaward electric water heater tank ,thus heating it and warming our coach.  As this system uses the water pump(hours)  in the Hurricane system we will not use it unless the temps get really cold ,when  we  worry about freezing the basement which space heaters will not warm up.

I often leave the Hurricane on but set the thermostats so they are below the temp I would like the electric space heaters to keep the coach at.  Since the basement thermostat is preset to something like 38F this ensures that the Hurricane would turn on if it was needed either in the basement or the coach.   We always like to have the Hurricane on since we are addicted to the infinite hot water it is capable of providing.  It doesn't really use all that much fuel; I checked my fuel gauge today and I've used less than ~1/8 of the tank in a month despite having had it on quite a bit during a rather cold snap early in December.  Since we're at a CG that charges for electric usage, it doesn't really matter whether I use diesel or electric for heat, as long as I don't have to pull out to go fill the tank.

[Tom and Pam Brown]

Would love to see a schematic of the heating systemic available to see how it actually is supposed to work.

The manual says to only turn on coach heat imguess the engine pre heat should be on too.

[Gerald Farris]

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.

Under the conditions that Jeremy described, if the "coach heat" switch is on and the water heater is being heated electrically, there will be some heat transfer from the water heater to the Hurricane fluid, so you can receive some heat in the coach with the heat exchanger fans running. As commented above, this is not the most efficient heating method, however it does work, but only on coaches that are set-up like the 2000 Marquis, with a Hurricane heater, electric water heater, and separate pump systems with separate switches.

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 Farris]

There seams to be some confusion here with the different operating systems in the Hurricane and AquaHot units. About the only similarity is that they both burn diesel.

The AquaHot unit operates like a fuel injection system with a high pressure pump spraying diesel through a nozzle to atomize it as air is blown into the combustion chamber and a high voltage spark across a gap between two electrodes ignites the fuel/air mixture.

The Hurricane functions like a carburetor. Compressed air is blown through a nozzle where it draws diesel into the air stream with the drop in pressure as the air goes through the nozzle. The air/fuel mixture is ignited by a 12V hot wire (no transformer needed) as the mixture flows across it. The fuel pump in a Hurricane is a low pressure pump (less than 4 PSI) and is controlled by a pressure regulator that will only allow the fuel to flow through the nozzle if there is negative pressure. In other words fuel can only flow into the combustion chamber if it is sucked into the air stream at the nozzle.

Also the AquaHot unit has a 120V heating element and the Hurricane does not. However some, but not all coaches that are equipped with a Hurricane system also have a separate water heater that is equipped with a 120V element.

Gerald

[Edward Buker]

Gerald,

Thanks for that info. Never worked on a Hurricane system and my assumption is that it had a typical oil burner arrangement with a nozzle and electrodes.....live and learn. BTW happy New year to you and Glenda.

Later Ed