Classic Winnebagos & Vintage RVs

Topic Boards => Chevy - GMC Chassis => Topic started by: TerryH on November 02, 2015, 06:45 PM

Title: Removing rear (engine supplied) heater and hot water pre-heat
Post by: TerryH on November 02, 2015, 06:45 PM
I am changing my hot water to on demand and won't need the engine preheat exchanger in the hot water tank any longer. Also the engine water hoses which come thru the floor to the hot water tank interfere with other plans. As well, I never use the rear heater and don't really like the idea of a rear pressurized leak while driving. How long until you noticed it spewing out water and anti freeze?
Question is (finally) could I expect a problem if I do a simple "loop" at the engine/heater to eliminate all water hoses to the rear? I seem to recall, back in my hippy and school bus days removing approx. six rear under seat heaters from the bus and having water pump problems. As I recall I was told that the water pump was higher pressure than normal - too high for the lowered requirements.
Anyone know if that is correct, or who has done this?
Thanks
Terry
Title: Re: Removing rear (engine supplied) heater and hot water pre-heat
Post by: DaveVA78Chieftain on November 02, 2015, 07:06 PM
Winnebago just added the hoses and water heater.  They did not mod the 454 water pump.  You can loop the system without any issues.
Title: Re: Removing rear (engine supplied) heater and hot water pre-heat
Post by: TerryH on November 02, 2015, 07:19 PM
Thank you, Dave.
Title: Re: Removing rear (engine supplied) heater and hot water pre-heat
Post by: cncsparky on November 02, 2015, 07:37 PM
I did the same.  There were two "Y"s above the front right tire area.  I removed them and installed hose couplings, leaving the two hoses going to the rear unconnected.  You will need both 5/8"and 3/4" hose couplings, available at auto parts stores.
Title: Re: Removing rear (engine supplied) heater and hot water pre-heat
Post by: circleD on November 02, 2015, 08:55 PM
I just cut the hose in the right fender well that went to the rear and back. So now I have a short spliced piece that goes from the water pump to the block. Mine started to seep through the old hose under the living area in the rear. I wasn't about to run new hose all the way back and back to the front in that tight area. So when I had the fuel tank down, I pulled the old heater hose out and took the blower out from under the bed. One less leak to worry about.
Title: Re: Removing rear (engine supplied) heater and hot water pre-heat
Post by: HandyDan on November 02, 2015, 10:43 PM
I had the wonderful experience of the rear heater spewing antifreeze all over the bedroom and carpet while driving down the road with no shoulder to pull over onto.  Not a pretty sight.  I removed it all.  I never used the rear heater, anyway.  It does shampoo out of the carpet pretty easy, though.  I don't think you can even get a replacement for the rear heater.
Title: Re: Removing rear (engine supplied) heater and hot water pre-heat
Post by: Rickf1985 on November 03, 2015, 09:43 AM
Those heaters are easy to come by and if you replace the hoses every ten years you will never have to worry about a leak. Te lines running front to back are metal lines and also can be replaced one time and forgotten. I have found it nce to get to where I am going and have hot water without having to turn on the hot water heater. I realize that once this heater goes bad that it would be very hard to find a replacement for that but the rear heat is also nice for long trips in cool weather. Mine heats the whole place pretty quickly which means I do not have to run the gas heater while driving. For summer use just put two ball valves in there, one in each line up front and valve off the back and then no heat to the back and no water flow either.
Title: Re: Removing rear (engine supplied) heater and hot water pre-heat
Post by: DaveVA78Chieftain on November 03, 2015, 06:34 PM
Rear Heaters (http://www.discountvantruck.com/rvrearaircondoitioners/rvheaters.htm)
Title: Re: Removing rear (engine supplied) heater and hot water pre-heat
Post by: TerryH on November 03, 2015, 08:19 PM
Thanks again Dave and everyone else. Had no idea that the rear units are that costly - I gave away half a dozen or so from a school bus.
As previous I am going to on demand hot water which makes the pre-heat redundant. Also, where the pre-heat lines enter the coach are in a lousy spot for what I am doing. As well, I don't use the rear (engine fed) heater.
When I remove it, should anyone here have use for it you can have it for shipping cost. Be aware I am in Canada.
Again, thanks to all.
Title: Re: Removing rear (engine supplied) heater and hot water pre-heat
Post by: Rickf1985 on November 04, 2015, 07:23 AM
I know I have seen box heaters for step vans cheaper than that, but then again that was a while ago. There are LOTS of school buses in junk yards but I would guess the heaters are history due to the copper for scrap.
Title: Re: Removing rear (engine supplied) heater and hot water pre-heat
Post by: ClydesdaleKevin on November 04, 2015, 09:59 AM
Yep.  I looped mine off at the water heater itself when I installed the Girard on demand heater...in case I didn't like the on demand heater and wanted to go back to the stock configuration.  That said, I DO like the Girard system now that we are used to it and it saves us a fortune on propane (over 60% less propane used per month).  It is stilled looped at the water heater though, since I haven't gotten around to looping it at the engine yet...lol!

Kev
Title: Re: Removing rear (engine supplied) heater and hot water pre-heat
Post by: tmsnyder on May 20, 2016, 09:32 AM

I'm also considering removing the rear heater lines.  I don't like the idea of a potential coolant leak, especially in the back room or underneath the body while on the highway.  I'm not planning any cold weather driving with the family.

Rick you said you valved them off for summer use?  That's also a nice option.  So you just open the doghouse to get access to the valves?

Another question about that rear heater (not covered by the owners manual)  what controls the blower?  I'm assuming there's a blower to circulate cabin air through the heater, what controls it?
Title: Re: Removing rear (engine supplied) heater and hot water pre-heat
Post by: Rickf1985 on May 20, 2016, 11:00 AM
I did not valve mine off but that is an option. I am probably going to valve off just the rear heater since I like having the free hot water.
Title: Re: Removing rear (engine supplied) heater and hot water pre-heat
Post by: hemi354az on May 20, 2016, 02:35 PM
Smaller, larger, cheaper . . . pick one (or more) . . .
https://www.google.com/search?q=hot+rod+heaters&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwiJhZP6pOnMAhVBFh4KHRXBBnMQsAQIXg&biw=1920&bih=955
Heat ON ! Lou FMC#120
Title: Re: Removing rear (engine supplied) heater and hot water pre-heat
Post by: Rickf1985 on May 20, 2016, 03:12 PM
Ours already have the heater in them, the thread was about disconnecting them.
Title: Re: Removing rear (engine supplied) heater and hot water pre-heat
Post by: JerryP on May 20, 2016, 10:37 PM

Just valve it off, incase you want to put it back.
I valved the whole rear end heater box, and water tank preheater, so I could use it as needed. or shut it off in case of a leak.
I am not concerned so much about the water heater, as the ability to have heat in the coach on chilly, or cold days.


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Title: Re: Removing rear (engine supplied) heater and hot water pre-heat
Post by: dickcarl on July 28, 2016, 10:34 PM
First really long drive on a really hot day.  Went in the bedroom to get something, and the little nightstand was hot enough to cook eggs on.  Couldn't get the hoses cut off fast enough.
Title: Re: Removing rear (engine supplied) heater and hot water pre-heat
Post by: Getoutdigin on July 30, 2016, 08:37 PM
I just made this exact plumbing change, exactly. Bypassed the rear system, came out of the intake in thru the heater core, out into radiator. I have already installed valves at the water heater because I have installed an aux. hydronic heater in bedroom. Different story