REST/Booster Engine Pre-heat with DPDT Switch Modification

norths03

New member
I'm finally getting around to doing this mod. If I don't use the REST/BOOSTER functions normally could I just hide the DPDT switch and leave it activated and just push the REST button when preheating or would leaving just the DPDT switch on cause a battery drain or other issues?
 

Aqua Puttana

Poly - Thread Finder
I'm finally getting around to doing this mod. If I don't use the REST/BOOSTER functions normally could I just hide the DPDT switch and leave it activated and just push the REST button when preheating or would leaving just the DPDT switch on cause a battery drain or other issues?
It probably won't work that way. The electric coolant pump power and REST timeout is what I leveraged for the Espar to run for engine preheat.

The problem with your idea is that the Aux Electric Coolant Pump is energized/powered anytime that the engine is running. Leaving the DPDT switch in the full time Espar enable (preheat) position would have the Espar firing up whenever the engine was running.

The Espar would supplement the engine heat until the Espar combustion module coolant temperature monitor was satisfied.

vic
 

norths03

New member
It probably won't work that way. The electric coolant pump power and REST timeout is what I leveraged for the Espar to run for engine preheat.

The problem with your idea is that the Aux Electric Coolant Pump is energized/powered anytime that the engine is running. Leaving the DPDT switch in the full time Espar enable (preheat) position would have the Espar firing up whenever the engine was running.

The Espar would supplement the engine heat until the Espar combustion module coolant temperature monitor was satisfied.

vic
Thanks, that makes sense. I'll just plan to flip the switch when it's needed. So if I let the lady friend use the van and she forgets to turn the switch off after preheat (she forgets to turn off the interior lights and kills the battery more often than I'd like so this is a real possibility), would she be at risk of draining the battery when the van isn't running or just at risk of running the Espar whenever the vehicle is running? Is there a failsafe that could be added to help the forgetful types with this?
 

Aqua Puttana

Poly - Thread Finder
Thanks, that makes sense. I'll just plan to flip the switch when it's needed. So if I let the lady friend use the van and she forgets to turn the switch off after preheat (she forgets to turn off the interior lights and kills the battery more often than I'd like so this is a real possibility), would she be at risk of draining the battery when the van isn't running or just at risk of running the Espar whenever the vehicle is running? Is there a failsafe that could be added to help the forgetful types with this?
I can't help with interior lights and memory.

If the DPDT switch is forgotten it will just run the Espar heater while the engine is running. That will add service hours to the heater, but won't hurt anything. The Espar combustion control module will shutdown heat when the engine is at operating temperature (above 167F coolant temperature). (I'm quite certain that 167F is the official Espar setting, but may be a bit higher or lower in practice.)

If the switch is left in Pre-heat position it will not drain the battery.

vic
 

norths03

New member
I can't help with interior lights and memory.

If the DPDT switch is forgotten it will just run the Espar heater while the engine is running. That will add service hours to the heater, but won't hurt anything. The Espar combustion control module will shutdown heat when the engine is at operating temperature (above 167F coolant temperature). (I'm quite certain that 167F is the official Espar setting, but may be a bit higher or lower in practice.)

If the switch is left in Pre-heat position it will not drain the battery.

vic
Thanks again for the quick reply. That's great news about it not draining the battery. I don't mind putting additional hours on the OEM Espar so that shouldn't be an issue. In fact there may be a real benefit to leaving the switch on since the Espar is supposed to be run monthly anyway for maintenance. We typically only use the van a couple of weekends a month so we're at risk of not running the OEM Espar enough as is. I'll consider it my winter/Espar service switch and leave it on at least through the winter and possibly the summer for maintenance purposes.
 

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