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Re: [GMCnet] Just another on-demand water heater [message #185917] Sat, 29 September 2012 14:56 Go to next message
KB is currently offline  KB   United States
Messages: 1262
Registered: September 2009
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Senior Member
I've noticed that all the pics of this heater install always show
the heater and ducts, but nobody ever talks about the water line hook-ups.

We ran into an interesting problem on our recent install:
if you just naively tap into the "hot" and "cold" lines under the sink,
you create a parallel hot water circuit. If the route through the regular
water heater has less drag than through the demand heater, you end up
with little to no flow through the new heater. In our case, it was such
low flow the demand heater wouldn't even kick on. Oops. I think even
if you get enough flow to trigger the demand heater, you could maybe
still end up with some strange dynamics.

The choices we've figured are either use the old water heater output
as the "cold" inlet to the demand heater (ie, plumb it in series),
or put a valve on the old heater to shut off flow through it
when you want to use the demand heater.

Just curious if others have run into this issue, or if we were just
particularly dumb or unlucky in our initial install.

thanks
Karen
1973 23'
1975 26'


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Karen 1975 26' San Jose, CA
Re: [GMCnet] Just another on-demand water heater [message #185923 is a reply to message #185917] Sat, 29 September 2012 17:01 Go to previous messageGo to next message
zhagrieb is currently offline  zhagrieb   United States
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Registered: August 2009
Location: Portland Oregon
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Senior Member
I plumbed mine in parallel with shutoff valves on both. That gives me the option to use either. The on demand, however, has shown itself to be one of the best mods I've made. Glenn

Glenn Giere, Portland OR, K7GAG '73 "Moby the Motorhome" 26'
Re: [GMCnet] Just another on-demand water heater [message #185944 is a reply to message #185923] Sat, 29 September 2012 19:50 Go to previous messageGo to next message
WD0AFQ is currently offline  WD0AFQ   United States
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Registered: November 2004
Location: Dexter, Mo.
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Senior Member
I just tapped the cold water line, under the sink. We did not plumb the entire coach, but kept the elec water heater for when we have electricity. We only needed hot showers, when dry camping, so that is what we did. When plugged in we use the electric water heater. I think I am pretty much the only one that went the "short route" on this, but that is all we wanted.
Works like a top. Keep the flow rate set on minimum and the temp will vary depending on how cold the water is in the tank under our bed.
dan


3 In Stainless Exhaust Headers One Ton All Discs/Reaction Arm 355 FD/Quad Bag/Alum Radiator Manny Tran/New eng. Holley EFI/10 Tire Air Monitoring System Solarized Coach/Upgraded Windows Satelite TV/On Demand Hot Water/3Way Refer
Re: [GMCnet] Just another on-demand water heater [message #185970 is a reply to message #185917] Sun, 30 September 2012 08:11 Go to previous message
JShot is currently offline  JShot   United States
Messages: 485
Registered: October 2006
Location: NW Ohio
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Senior Member
KB wrote on Sat, 29 September 2012 15:56

I've noticed that all the pics of this heater install always show
the heater and ducts, but nobody ever talks about the water line hook-ups....

Just curious if others have run into this issue, or if we were just
particularly dumb or unlucky in our initial install.

thanks
Karen



Karen,
No, you were not dumb, just maybe unlucky - your layout is different.

One of the 'good' things about a Royale Center Kitchen is that the old water heater is/was under the bunk bed right next to the reefer dividing wall. It was an easy chore to just push the hot and cold water lines back under the false floor that the reefer sits on, and drill a hole in that floor, and pull the lines up to right under the new propane heater. The lines hooked right up to the new heater without any other adapters. An easy install Very Happy

John


John Shotwell
Ridgeville Corners, OH
78 Royale Center Kitchen
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