HWH 40 amp fused pump not supposed to be powered by coach batteries?...why?

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soyjer

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Jul 12, 2014
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[NOTE: I found my answer here:
http://www.irv2.com/forums/f104/hwh-system-acting-up-234391-3.html

"hwh has used the same procedure since 1967. the batteries used to operate the hwh system is the choice of the manufacturer.
we recommend connecting to the chassis batteries.
almost all mfg's use the chassis batteries. if the batteries are low, the engine alternator can provide the additional amperage need to operate our system.
the pump motor draws about 105 amps to start up. when the motor reaches the needed rpm's, the draw drops back to about 95 amps. this draw depends on which motor is used, but the premise is the same.
if you have a 750 cranking amp battery, why wouldn't it supply the 105 amps needed to start the motor? unless it is depleted to the point. it below the required voltage, , it should be sufficient. there is a low voltage warning light on the touch panel.
if you continue to try to run the leveling system on a low battery, it could possibly burn out either the motor, control box, or even a 12 volt relay. its not a common problem, because most users recognize the problem and stop trying to get the system to do something it wasn't designed to do.
in any case, we do not have a problem with our system running on the chassis battery, without being plugged in.
running the generator, or plugging in to shore power doesn't have much if any effect on the hwh system, because it is normally connected to the chassis battery.
if anyone has questions, please feel free to call me at 602-549-3638
thanks, paul maddox"

Sounds like my best bet, since my pump is connected to the coach batteries, is to push and hold the emergency start switch (connecting coach batteries to chassis batteries) while using the HWH system.

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Original post:

[EDIT: The power cable to the pump from the battery actually has a 200 amp fuse in it, not a 40 amp fuse. The 40 amp fuse goes to the control box to power the solenoids. I don't know how many amps the pump plus two solenoids would draw.]

Several HWH service manuals, including mine for my 310 series (2003), regarding powering of the hydraulic pump, say:
"The engine battery supplies power for the control box and hydraulic pump. DO NOT use the coach batteries to supply power to the pump."
Does anyone out there know why HWH would not want the pump powered by the coach batteries?
Is it because amps drawn by the pump plus two solenoids is too much power draw for the coach's deep-cycle non-cranking type batteries?

My 310 system was installed by the dealer approximately 1 year after purchase of the coach, and the pump is powered by the coach batteries. The pump power cable runs through a 200 amp fuse to the coach power terminal of the nearby generator start solenoid relay.
 
soyjer said:
Does anyone out there know why HWH would not want the pump powered by the coach batteries?
Is it because 40 amps is too much power draw for the coach's deep-cycle non-cranking type batteries?

That very well could be. The chassis batteries tend to produce high amperage for a short period of time, thus being able to start your motor.  Also if the motor is running, then your 100+ amp alternator is supplying high amps right to the starting batteries. 

They could be worried about the house battery bank being pulled down, amperage dropping and the pump motor heating up. 
 
You were correct on both counts...see above.
Thanks
 
As I understand it, RVIA standards now require that levelers and slides be powered from the chassis batteries. Also the entry steps, but that's for safety reasons.
 
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