HydoHot

[Linda Bodkin]

Any hints out there on starting the HydoHot in really cold weather. -20C. We are planning on heading out shortly and need to get the heat on in the motorhome. Do I need to have the generator running? Any help would be appreciated.

[Marty and Suzie Schenck]

If your batteries are all charged up or you are plugged in, just flip the switch on the diesel burner on and it should fire right up. That is of coarse providing it worked in the first place. At those temps the electric element really would not help at all. Marty

[David T. Richelderfer]

Assuming 1> the hydrohot unit is in operating condition, and 2> you have diesel in the tank above the 1/4 full level, and 3> it's winterized diesel if really cold, and 4> you have sufficient electrical power for diesel ignition, then it should spark and ignite the diesel to flame.   -20 C converts to -4 F, I believe.  So that diesel, if not winterized, is getting close to its gel point, meaning the wax in the diesel is changing to solids.  When diesel gels from excessive cold temperatures, then the wax solids will plug the diesel filter... which in turn stops the flow of diesel to the burner.

http://www.aquahot.com/eSource/ecom/eSource/staticpages/documents/HHE-200-09EandHHE-500-09MHydro-HotOwnersManual08-23-04_001.pdf

[Linda Bodkin]

The batteries are now up, I did have a problem with the Pro-Sine being too cold. I have now corrected that problem. The generator will start so I am assuming there shouldn't be a problem with the diesel fuel. The HydoHot starts but doesn't ignite. It was all serviced in Oregon at the Rally so should be in good condition and was working when we winterized it in October. We were planning on leaving tomorrow but may be delayed. The temperature is supposed to get up to -7C tomorrow so maybe we have to wait it out.

[Linda Bodkin]

Just tried it again, still no luck. It will come on but it won't fire up.

[Harvey Ziegler]

Linda.
It should fire up at those temperatures but 1 thing to check is the low voltage cut-off on the control panel board. If it is indicating a red light then you will need to press the low voltage reset button near the top center of the board. This reset has caught me a couple of times if you have turned the batteries off for storage.

[Edward Buker]

Linda,

I have a AquaHot which is different so I am not sure of all your options. Cold does affect the spray pattern of the nozzle due to fuel viscosity change, the pump pressure may be lower due to lower voltage available and more mechanical drag, and ignition by spark may be affected if the mist of fuel is not quite right along with the air flow being provided.

If there is an option to use an engine coolant loop to heat the HydoHot  or an auxiliary heater with an electric element that can circulate and heat the HydroHot you will have a much better chance at getting ignition. If you do not have that option then I would have the generator running or some source of charging voltage on the batteries for a reasonable period of time before I tried to fire up the HydroHot. Warm batteries will provide more output and charging will raise the temperature some. Also the voltage level will be higher which will provide a better chance of ignition of the HydroHot. If you had a ceramic plug in heater with a fan, like a Polonius Disk furnace, and let it run overnight in the HydroHot compartment it could possibly help. It would take quite some time to bring the temperature up of the furnace given the cold but every bit of advantage might help.

Later Ed

[Bill Sprague]

Linda,

You suggested the batteries had been low.  That means I would second the suggestion that the HydroHot reset button may need a push.  On ours, it is recessed and you need a tooth pick to do it.  It is tiny, so don't push hard.

It may help if you turn the electric side on for an hour or so.  It would not warm the motorhome, but it would warm the HydroHot.  The diesel might light if it was warmer.  

[Orman Claxton]

Hello Linda
Please feel free to contact me, maybe I can get you started
Thanks
Orman

[Linda Bodkin]

Thanks to everyone for their help. I had to get the fuel nozzle replaced. It is now working. Our weather has also warmed up some.