Home » Public Forums » GMCnet » [GMCnet] Checking my understanding of heater hose routing
| [GMCnet] Checking my understanding of heater hose routing [message #317627] |
Tue, 16 May 2017 16:35  |
Richard Denney
Messages: 920
Registered: April 2010
Karma: 9
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Senior Member |
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When installing the new engine, we noticed that the heater hose routing on
my coach was not original, and incorrect. My routing WAS: from rear of
manifold back to the house water heater, then from water heater to
dash-heat heater core (through a vacuum-switched heater control valve),
then from heater core to fitting on top of water pump. With this
arrangement, if the dash heat is turned off and the heater control valve
closed, the house water heater won't heat. That was the symptom: A COLD
shower during the drive down to Georgia. I usually don't depend on the
engine coolant to make hot water, meaning I usually don't take a shower as
soon as I stop driving. I do recall having hot water on one prior
occasion--perhaps I was running the dash heat (that may have been before I
replaced the heater control valve, which has been several years).
I looked at a coach in Bean Station, which was plumbed like this: Back of
manifold to tee, which branched to house water heater and heater core, and
top of water pump to tee, which branched to house water heater and heater
core. That seems correct to me.
I'm doggoned if I can find a heater hose routing diagram in the manual or
parts book.
At what point is the hose supposed to change from 5/8" (which comes from
the back of the manifold) to 3/4"? My guess is at the heater core, but I'm
also assuming that it will be 3/4" on the outflow barb on the house water
heater.
Thus, I'm assuming 5/8" hose from the rear of the manifold to a 5/8" tee,
which splits to feed 5/8" hose to the house water heater, and 5/8" hose to
the heater core, through the heater control valve.
And then 3/4" hose from the water pump to a 3/4" tee, which splits to feed
3/4" hose to the house water heater and 3/4" hose to the heater core.
Do I have that right?
Rick "no more cold showers" Denney
--
'73 X-Glacier 230 "Jaws"
Northern Virginia
Offlist email: rick at rickdenney dot com
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| Re: [GMCnet] Checking my understanding of heater hose routing [message #317631 is a reply to message #317627] |
Tue, 16 May 2017 16:51  |
Kingsley Coach
Messages: 2691
Registered: March 2009
Location: Nova Scotia Canada
Karma: -34
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Senior Member |
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Rick
We don't hear near enough from you !
Plumbing isn't my bag, but greater minds than mine will be here soon...
Mike in NS
On Tue, May 16, 2017 at 6:35 PM, Richard Denney wrote:
> When installing the new engine, we noticed that the heater hose routing on
> my coach was not original, and incorrect. My routing WAS: from rear of
> manifold back to the house water heater, then from water heater to
> dash-heat heater core (through a vacuum-switched heater control valve),
> then from heater core to fitting on top of water pump. With this
> arrangement, if the dash heat is turned off and the heater control valve
> closed, the house water heater won't heat. That was the symptom: A COLD
> shower during the drive down to Georgia. I usually don't depend on the
> engine coolant to make hot water, meaning I usually don't take a shower as
> soon as I stop driving. I do recall having hot water on one prior
> occasion--perhaps I was running the dash heat (that may have been before I
> replaced the heater control valve, which has been several years).
>
> I looked at a coach in Bean Station, which was plumbed like this: Back of
> manifold to tee, which branched to house water heater and heater core, and
> top of water pump to tee, which branched to house water heater and heater
> core. That seems correct to me.
>
> I'm doggoned if I can find a heater hose routing diagram in the manual or
> parts book.
>
> At what point is the hose supposed to change from 5/8" (which comes from
> the back of the manifold) to 3/4"? My guess is at the heater core, but I'm
> also assuming that it will be 3/4" on the outflow barb on the house water
> heater.
>
> Thus, I'm assuming 5/8" hose from the rear of the manifold to a 5/8" tee,
> which splits to feed 5/8" hose to the house water heater, and 5/8" hose to
> the heater core, through the heater control valve.
>
> And then 3/4" hose from the water pump to a 3/4" tee, which splits to feed
> 3/4" hose to the house water heater and 3/4" hose to the heater core.
>
> Do I have that right?
>
> Rick "no more cold showers" Denney
>
> --
> '73 X-Glacier 230 "Jaws"
> Northern Virginia
> Offlist email: rick at rickdenney dot com
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Michael Beaton
1977 Kingsley 26-11
1977 Eleganza II 26-3
Antigonish, NS
Life is too short to hold a grudge; slash some tires and call it even !
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| Re: [GMCnet] Checking my understanding of heater hose routing [message #317634 is a reply to message #317627] |
Tue, 16 May 2017 17:30 |
C Boyd
Messages: 2629
Registered: April 2006
Karma: 18
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Senior Member |
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There is a 5/8 T in the back. The 3/4 T in The front has a 5/8 barb to go to water heater.
Richard Denney wrote on Tue, 16 May 2017 17:35When installing the new engine, we noticed that the heater hose routing on
my coach was not original, and incorrect. My routing WAS: from rear of
manifold back to the house water heater, then from water heater to
dash-heat heater core (through a vacuum-switched heater control valve),
then from heater core to fitting on top of water pump. With this
arrangement, if the dash heat is turned off and the heater control valve
closed, the house water heater won't heat. That was the symptom: A COLD
shower during the drive down to Georgia. I usually don't depend on the
engine coolant to make hot water, meaning I usually don't take a shower as
soon as I stop driving. I do recall having hot water on one prior
occasion--perhaps I was running the dash heat (that may have been before I
replaced the heater control valve, which has been several years).
I looked at a coach in Bean Station, which was plumbed like this: Back of
manifold to tee, which branched to house water heater and heater core, and
top of water pump to tee, which branched to house water heater and heater
core. That seems correct to me.
I'm doggoned if I can find a heater hose routing diagram in the manual or
parts book.
At what point is the hose supposed to change from 5/8" (which comes from
the back of the manifold) to 3/4"? My guess is at the heater core, but I'm
also assuming that it will be 3/4" on the outflow barb on the house water
heater.
Thus, I'm assuming 5/8" hose from the rear of the manifold to a 5/8" tee,
which splits to feed 5/8" hose to the house water heater, and 5/8" hose to
the heater core, through the heater control valve.
And then 3/4" hose from the water pump to a 3/4" tee, which splits to feed
3/4" hose to the house water heater and 3/4" hose to the heater core.
Do I have that right?
Rick "no more cold showers" Denney
--
'73 X-Glacier 230 "Jaws"
Northern Virginia
Offlist email: rick at rickdenney dot com
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C. Boyd
76 Crestmont
East Tennessee
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| Re: [GMCnet] Checking my understanding of heater hose routing [message #317637 is a reply to message #317627] |
Tue, 16 May 2017 17:41 |
Emery Stora
Messages: 959
Registered: January 2011
Karma: 4
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Senior Member |
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I can go out and lift my motor box cover in the morning and check, but I am certain that both hoses going to the house water heater are 5/8” hose.
I’ll check where the 3/4” go and the other connections and let you know.
Emery Stora
> On May 16, 2017, at 3:35 PM, Richard Denney wrote:
>
> When installing the new engine, we noticed that the heater hose routing on
> my coach was not original, and incorrect. My routing WAS: from rear of
> manifold back to the house water heater, then from water heater to
> dash-heat heater core (through a vacuum-switched heater control valve),
> then from heater core to fitting on top of water pump. With this
> arrangement, if the dash heat is turned off and the heater control valve
> closed, the house water heater won't heat. That was the symptom: A COLD
> shower during the drive down to Georgia. I usually don't depend on the
> engine coolant to make hot water, meaning I usually don't take a shower as
> soon as I stop driving. I do recall having hot water on one prior
> occasion--perhaps I was running the dash heat (that may have been before I
> replaced the heater control valve, which has been several years).
>
> I looked at a coach in Bean Station, which was plumbed like this: Back of
> manifold to tee, which branched to house water heater and heater core, and
> top of water pump to tee, which branched to house water heater and heater
> core. That seems correct to me.
>
> I'm doggoned if I can find a heater hose routing diagram in the manual or
> parts book.
>
> At what point is the hose supposed to change from 5/8" (which comes from
> the back of the manifold) to 3/4"? My guess is at the heater core, but I'm
> also assuming that it will be 3/4" on the outflow barb on the house water
> heater.
>
> Thus, I'm assuming 5/8" hose from the rear of the manifold to a 5/8" tee,
> which splits to feed 5/8" hose to the house water heater, and 5/8" hose to
> the heater core, through the heater control valve.
>
> And then 3/4" hose from the water pump to a 3/4" tee, which splits to feed
> 3/4" hose to the house water heater and 3/4" hose to the heater core.
>
> Do I have that right?
>
> Rick "no more cold showers" Denney
>
> --
> '73 X-Glacier 230 "Jaws"
> Northern Virginia
> Offlist email: rick at rickdenney dot com
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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| Re: [GMCnet] Checking my understanding of heater hose routing [message #317814 is a reply to message #317673] |
Sat, 20 May 2017 20:50 |
Richard Denney
Messages: 920
Registered: April 2010
Karma: 9
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Senior Member |
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So, as it turns out, I put in the tees but didn't run the house water
heater loop back to the water heater. I made the tees from Dorman heater
hose fittings (steel, with smooth nipples instead of sharp barbs and 1/2"
pipe threads) into anodized forged aluminum pipe-thread tees intended for
use with automotive heater hoses. I found a deal on those at the local
Carquest, and they looked a bit better than house-plumbing alternatives.
But the real story is the ridiculous water heater installed two or three
PO's ago. It's a round, six-gallon heater, like a home unit, but since it
had heat exchanger fittings, I assumed it was for RV use. Not so. When I
tried to remove the engine coolant hoses, I discovered that the exchanger
was in fact just a homemade loop of 1/2" copper tubing that enters and
exits from a jagged hole cut in the sheet metal shell at the bottom, under
the actual tank. It appeared that the tubing just made a circuit through
the insulation, or something like that. I decided I didn't need engine heat
badly enough to tolerate that foolishness, so I will just leave it as is
for now, remove all the old heater hose running to it, cover the hole in
the floor, and run it as the electric-only water heater it was designed to
be.
I have a long-term plan to redo the cabinet in the galley, which was
cheaply done with too many drawers that are each too small. When I do that,
I'll do it in a way the makes the furnace more serviceable, and that gives
me a chance to consider where I can put an Atwood water heater, maybe with
a propane alternative.
I tried to start the engine to circulate and top off the coolant, and to
check for leaks, and the battery, new last year, was at 10 volts and
wouldn't even click the solenoid. I'm not buying that the battery died that
suddenly, and I don't think any residual drain wouldn't have been overcome
by the PD9240 that is always plugged in. I hooked up jumper cables from my
little Toyota truck, and nothing. Then, suddenly, a good connection and the
455 cranked right up. Alternator is at 14 volts. Gotta go back and check
cables--I think something may have gotten loose. I'll do that tomorrow.
Rick "noticed that the oil pressure fitting is seeping, too--gotta redo
that" Denney
On Wed, May 17, 2017 at 7:43 AM Richard Denney wrote:
> Thanks, guys, for the explanations of your heater hose plumbing. I have a
> couple of new tees that I bought, with 1/2" NPT heater-hose barbs to screw
> into them. (These barbs don't have the sharp barbs of brass fittings, but
> are steel with rounded barbs made by Dorman). Looks like I need to change
> one of my 3/4" fittings with a 5/8" fitting for the return run from the
> house water heater, though now I recall seeing a coupler that might well be
> a reducer--I can deal with that at the time. But at least I know how I'm
> going to plumb it to be correct.
>
> As for that sharp bend going up through the floor to the house water
> heater, I need to look at see what was done before, but a couple of elbows
> or preformed sweeps seem like it would replace the bends that might tend to
> kink.
>
> Rick "as usual, trying to collect all the parts necessary before starting
> the project" Denney
>
>
> --
> '73 X-Glacier 230 "Jaws"
> Northern Virginia
> Offlist email: rick at rickdenney dot com
>
--
Rick Denney
73 x-Glacier 230 "Jaws"
Off-list email to rick at rickdenney dot com
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