Reporpoising the rear heater system

[Doktari]

On my 1995 Chevy Van G30 shortie microbird I don’t like the heater hose draped across the front of the engine compartment then along the drivers side of the engine then going back to the rear of the bus. It’s in the way but not too bad. I can string up the heater hose when changing the spark plugs.
I don’t think I’d use the rear heater much, if ever, while I’m driving. Or while I’m parked. In fact I removed the rear heater already but the long tubes are still there.
However, I might repurpose that tubing. I like to build heated radiant floor systems and mini boilers in my rigs. This would be my third vehicle with a heated floor. I suppose I could run the heated boiler water in reverse and pre heat the engine rapidly?. By simply opening a valve. As I usually have a 6 gallon radiant heat buffer tank full of hot water all Winter long I could dump the heat into the engine?
That’s the only use I can think of for this tubing except for one other idea. Which is to put in a bypass on the engine heater hose tubing, bypassing the engine. The boiler water would go straight to the stock heater core to heat the bus. And the boiler would heat the infloor tubing.
I usually use propane as I’m lazy but I have designed small boilers that run on wood or pellets.
Ideally I’d rather be able to follow the sun and warmth and not bother with these systems anymore. But realistically I might get stuck in cold weather and need to be ready. A Olympian heater sure sounds nice and simple. Someone talk me out of this overengineered system please. Same with my solar. I tend to build them much to big. But I have learned a few things doing it.
Should building a AC system this time of year lol.

[peteg59]

Sounds like you have lots of disposable income and time to get into such elaborate floor heating system(s)?
The Olympian heater would be so much cheaper and less labor intensive, that it would be a no brainer in my book...
Good luck on your decision.

[Doktari]

Good points especially regarding lots of time doing custom heating and solar. The expense is relatively low in the scheme of things. If it’s mostly DIY. A lot of odds and ends found on eBay or at a few favorite industrial junk yards for pennies on the dollar. But it does start to add up.
I really like hydronic floor heat. It’s hard to go back once one has had it. And I hoped the efficiency would pay for itself over time.
I sort of hoped that I might invent a new system for vehicles and there are a few innovations in the systems I made. I also really like vented heaters and the option to use wood and passive solar thermal if desired or necessary. Boon-docking comes to mind.
There’s a website forum called Permies.com that has huge discussions of innovative stoves and water heaters. At least a few skoolies have rocket stoves on the Permies site. They can take a while to design and build so start now if you need it by Fall.
PEX pipe is so convenient and easy compared to copper. The floor heat part on a bus doesn’t cost much. Just a thin thermal break insulation layer (old carpet works ok), strips of plywood with heat transfer plates sitting in the gaps between the plywood strips, then snap the PEX into the heat transfer plates. I used the thinnest 1/4 cement board over the top. Then floor epoxy the cement board. It warms up in about 10-15 minutes. The plates conduct the heat from the tubes into the cement board quickly.
A pseudo boiler can be fairly simple. A homemade copper coil in a pot of water sitting on the stove is one of the simplest. It thermosyphons up to the hot water tank.
But it does eat up time that’s for sure.
Of course!! Another use for the heater hose running to the rear of buses is a marine hot water heater that has the heat exchanger coil in it to use engine coolant. Maybe some of the RV water heaters have a coil inside? And don't cost as much as marine!
It’s can be nice to do floor heat installation when the bus is empty and do the entire floor but a strip of floor heat down the center of a already converted bus works good too. I thought about inventing a kit that could be easily installed lengthwise down the bus.
Be careful to mark the tubing runs so no fasteners hit the tubing when framing or installing cabinets.
If a bus roof is going to be raised then extra insulation can be installed under the floor heat. This is the ultimate deluxe application. As I’m 6’6” tall I thought about specializing in customizing buses for tall people. I’m in the middle of the roof raise on mine.
One of the challenges is freeze protection. It would be very convenient if the domestic hot water could also be circulated through the floor heat. Freezing could ruin it the first time it’s forgotten. So a separate system with antifreeze or heat exchangers needs to be used. But there’s probably a way to easily drain plain water from a floor. Compressed air? This would great simplify the system.
Another important step is to always pressure test for leaks in the tubing before laying the floor over it. It’s a PITA to test it but well worth the trouble.

[CHEESE_WAGON]

Originally Posted by peteg59

The Olympian heater would be so much cheaper and less labor intensive, that it would be a no brainer in my book...

Pete, PM me, I'd like to know more about this Olympian setup, I've been contemplating a radiant subfloor myself.

[peteg59]

PM sent...
For clarification purposes here's a link to one of the Camco Olympian heaters:
https://www.amazon.com/Camco-57351-O...xpY2s9dHJ1ZQ==

The Olympian heaters are basically marketed as a secondary heating supply, depending on the installation.
They heat a relatively small SF area but are good for maintaining some form of heat in a well insulated bus.

[PNW_Steve]

A word of caution regarding that type of heater....

They put a significant amount of moisture in the air. I tried running one over a Winter in Western Washington. I had to buy a dehumidifier to keep the moisture under control.

I think I may still have it out in the garage..... If I happen across it, you can have it.....

[Doktari]

My experience also with any non vented propane heaters is run away moisture issue. But I keep one non vented Olympian (now Camco Wave) as a backup. I run it for a few minutes to knock the chill off while the vented floor heat, radiant, hydronic, gets warmed up and circulating.
The Olympian catalytic ( now Wave catalytic) is not radiant floor heat. There’s no liquid. Just efficient combustion of propane through a catalyst fiber. They are radiant however. They are nice in that it resembles sitting next to a glowing campfire.
One can put a vented hood over a non vented Wave then a air to air heat exchanger in the stack. I know a guy who has 3 air to air heat exchangers in his stack but then one needs a condensate trap and drain the condensate outside because his exhaust is so cool it condensates in the stack.
. I don’t know any simple way that’s optimal. Wood can make a incredible mess. Keep driving South.
I have too much moisture buildup even without a non vented heater.
PND, I’d take you up on that offer as my old Olympian is broken. I need vice grips on it to stay on.