Beautiful Banff in our OEV Summit and a hydronics dilemma

[Alloy]

The OP has already stated the cabin tank is expansion/overflow without recovery.

OK but if it is removed what allows air to excape from the system? The engine recovery tank could but it would need to be the highest point in the system.

......without seeing the system components I'll stop commenting.

 

[AntecTrek]

We took BLITZEN to Banff National Park for the week and enjoyed warmer conditions. The x-country ski trails are melting out fast and what is left is pretty icy. Nevertheless we had a great time skiing an area adjacent the Lake Louise ski hill that just reopened after a two year closure.

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After a couple of nights at Lake Louise we drove to Banff and the superb Tunnel Mountain campgrounds. It was very quiet and we shared hiking trails and viewpoints with only the elk.

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We have a winter ritual of snowshoeing up Sulpher Mountain's backside and down the front but this year, after walking a couple of miles to the trailhead, we found it closed! Turns out they are hauling and burning deadfall. So instead we hiked up and down the front tourist route under the gondola. In previous years one could get a free ride down if you walked up, but under new ownership and after extensive, expensive renovations the one-way ticket down was $25/person!! The cafeteria where you could enjoy your pack lunch while admiring the view is now a chic restaurant with reservations required. Ah, Banff....

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After several trips this winter in the OEV Summit, we've become very comfortable with its features and layout. The combination of our F350 cab/chassis and OEV's integrated cabin remains a pleasure to drive in all road and weather conditions. The extreme cold experienced during the Polar Vortex event in February confirmed that the Summit is completely suitable for such severe weather. We did discover a few locations of thermal bridging which created interior frost build-up and will have to give some thought to a remedy before any extended winter travels.

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The one issue that continues to annoy both OEV and us is the hydronics. OEV has attempted to remedy the issue and incremental improvements have been made. We still have a leak from the coolant overflow tank and, with this trip, one of the 2-way ball valves. OEV discovered early on that the truck engine produces more pressure than the Webasto, which is the apparent cause. At this point, it now leaks only in one scenario: when the truck circuit is used to heat the cabin's interior while driving down the road. If I reverse the situation and use the Webasto to pre-heat the truck engine, no leak. If I close off the truck circuit completely and heat the cabin with the Webasto, no leak. So I'm curious to hear from anyone else with hydronics experience - any leads or suggestions I can pass on at our next service trip?

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A post-trip wash always feels good. The winter studded tires have been exchanged for summer Method 701HD rims and BFG T/A KO2 tires. We also had Bushmaster front OE-style flares installed, along with Ford's plastic inner fender liners and front Gatorback mud flaps. Also considering swapping out the front air dam for a smaller version from the 2WD models but, knowing we will rack up more miles on highways than back roads, hesitate because of the possible effect on fuel economy. If it takes a bashing this summer, we can make the call.

Awesome view!

 

[JRhetts]

I confess I cannot follow all the details you have included. But after 150,000 miles with hydronic systems, I'll nevertheless suggest that you have an airlock [air bubble] in your loop. You migh add [as I did] an aux circulating pump with enough flow/pressure to clear any such. YMMV.

 

[Trail Talk]

suggest that you have an airlock [air bubble] in your loop. You migh add [as I did] an aux circulating pump with enough flow/pressure to clear any such. YMMV.

Thanks for sharing your experience . I will suggest this when it goes back to OEV in two weeks. Meanwhile we are heading to the mountains soon with a good supply of coolant .

 

[westyss]

This system diagram looks Wrong to me, it Does look like the engine coolant will not flow to the hot water tank, and seems like the two systems, webasto and truck coolant system are not working together.
having a split system is not a solution but just another complex way of having more things go wrong.
looking at the diagram I would get the truck and webasto in line, I am pretty sure that these hydronic heaters have flow through ability or at least an Espar has it so the truck coolant pushes through the webasto easily. This makes the system use the engine expansion tank and air locks should flow out unless there is a high point higher than the rad, if so then a small valve at the high point will be needed to drain out the air until coolant flows out, it may need to be bled out often.

Having coolant flow through the cabin hot air blower in the summer should not produce heat if the blower fan is off so no worries there.

A simple solution would be to take the coolant flow from the cabin blower into the truck circuit then to the hot water tank circuit. Eliminate the two circuits and make one. So, on the diagram the blue line leaving the truck goes to the right into the water tank circuit and not down in between the coolant tank and webast, no T off after the hot air blower.

Most likely the coolant tank is there to store more coolant to keep the webasto from cycling on too often or to have it stay on a lower heat mode.

 

[Trail Talk]

Update on our hydronics leaks; with the overnight temps staying above zero during our outing last week to Glacier National Park, we found the system did not leak. Perhaps this indicates that contraction of pipe connections due to cold was the cause?