Espar D4 Hydronic; heat/HW/preheat plumbing configuration

[Weaselblade]

I'm installing an Espar D4W to provide heat, hot water, and if required engine preheating, in a '97 E350 shortbus with a 7.3L powerstroke turbodiesel.

The bus already had a couple of rear heat exchangers plumbed to the engine in parallel with the front heater core, with gate-valves to simultaneously cut off flow to both front and rear heaters.

Current plan is to remove one rear heat exchanger as hopefully excess to requirements, given that the remaining heat exchanger is marked as 40K BTU/hr, and install things per this diagram. Suggestions welcome...



A few things to sort out:

1) Expansion tank; I've seen it suggested that this can be skipped by blocking flow on only 1 of the lines from the engine. Anyone see a downside?

2) The shutoff valves are already there, but I've seen conflicting information on the safety of running the engine with the heater core coolant flow shut off or bypassed. Wouldn't be any need to do so normally, but given the amount of plumbing involved I'd like my shutoffs to be in a location that leaves the vehicle drivable, just in case. Should I be replacing the shutoff valves with a bypass?

3) Coolant filter. Yes, no, where?

 

[Abitibi]

Subscribed!

I basically started the same propject on my ambo a while back. My project is on hold until I'm done working on my Patrol (I'm getting it ready to go for sale this spring).

I made some manifolds on mine with shut off valves at each ports to control where the heat goes... for some reason my design seems way more complicated :-S

Cheers
Mr. D

 

[Mwilliamshs]

http://www.expeditionportal.com/forum/threads/138258-Water-System
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^Might be a good read^
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Yes to expansion tank/accumulator in both loops (you likely already have one on the engine coolant side). Yes to coolant filter. Yes to bypass>shutoff. I plan to use the OE heater loop bypass from a late-model ford ranger mounted at the oe heater core and plumbed with the van hvac controls but to default to bypass so in case of a leak anywhere I don't have to do anything to close the loop.

 

[mp_tx]

Interested in how this works out--I too need a system for my ambo.