Hydronic vs. Non-Hydronic Heating. (Air & Water)

[EMTacoma]

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I'm fairly sure that's a standard option with the likes of Espar so with the built in timer on the control panel you get a warm interior and a pre-heated engine. You could also run a loop around your batteries, or Arctic Cat do an under battery tray to link up to the hydronic circuit.

Good point on the battery warmers. I'll look up the arctic cat also. I don't expect we'll be in situations where the outside temp is <20F, so I would guess I won't need them right now? Also if the block is heated, it will probably warm the engine bay. I know it does when the block heater is plugged in.

 

[EMTacoma]

I have a Espar hydronic only unit in my E350 van. I have the rear HVAC unit running off the "coach" batteries with a separate switch and thermostat. I can also run the front dash vents/controls with the key in acc position in engine preheat scenarios or to move more air/defrost windows without the engine running.
Having the separate airtronic/hydronic units would be nice for the redundancy with young kids around.

We also always have a little buddy heater for backup heat, so we should be able to use that as backup. Back when I had a tacoma, I did have once in labrador at -22F that the little buddy didn't work, but I think we'll be camping in much warmer temps.

 

[RPhil]

I have a Espar hydronic only unit in my E350 van. I have the rear HVAC unit running off the "coach" batteries with a separate switch and thermostat. I can also run the front dash vents/controls with the key in acc position in engine preheat scenarios or to move more air/defrost windows without the engine running.
Having the separate airtronic/hydronic units would be nice for the redundancy with young kids around.

Would you mind sharing how you tapped into your rear HVAC unit? Did you just run an additional 12V feed to the fans from the coach battery? Is there any concerns with tapping like that- I'm curious if you have to wire specifically to avoid backfeeding the circuit (or if that is even a problem).

So the Hydronic heater would just heat the coolant in a loop with its integral pump, including through the heater core, and then the fans can be activated via the coach battery- am I understanding this correctly?

I am planning something very similar. Also considering adding an Isotemp (or similar) coolant-heated hot water heater/calorifier to the same loop. Still in the planning stages, obviously.

Do vehicles with rear HVAC need to have the dial set to "rear" in order for the coolant to flow to the rear heater core, or does that "rear" setting only affect whether or not the fans are turning on.

 

[Korey H]

The way our system runs:
We have a shut off valve between the engine side and the Webasto living space side, the valve is only on one side of the loop.
engine on, Webasto off, valve open: engine heat heats calorifier and cabin(radiators controlled by individual valves(in summer you can heat domestic water only)
engine off, Webasto on,valve open: engine preheat, calirofier heat, cabin heat
engine off, Webasto on, valve closed, engine is out of loop, Webasto heating calorifier and cabin only. Cabin temperature controlled by a thermostat.

In summer the valve is just left open. In winter, closed when parked, open for preheat and driving.

This set up is also used on boats.

Sounds straight forward. It’s a manual valve? Planning for my install now and struggling to understand/ plan controls. With an 07 c5500 certainly appreciate engine pre heat. Then just need hot water. Thank you


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[Joe917]

Yes, manual ball valve.