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[GMCnet] Water heater questions [message #78470] Mon, 29 March 2010 18:48 Go to next message
bhayes is currently offline  bhayes   United States
Messages: 263
Registered: March 2010
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Senior Member
I had a few questions regarding the GMC water heaters that I hope someone
can answer.

* How many gallons does the side bathroom water heater hold?
* When it's running on electric, how many minutes of shower time can you
get?
* How long does it take to recover?
* How does it compare to the 6-gallon LP water heaters found in most RVs?

I've noticed that the rear-bath Coachmen Royales appear to have typical LP
water heaters, while the straight GMCs have the electric/engine coolant
water heaters.

Thanks!

Bryan
No GMC yet
Salt Lake City, UT
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Bryan Hayes
'76 Eleganza II
Salt Lake City, Utah
Re: [GMCnet] Water heater questions [message #78496 is a reply to message #78470] Mon, 29 March 2010 20:34 Go to previous messageGo to next message
David L Greenberg is currently offline  David L Greenberg   United States
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Registered: January 2004
Location: Port St Lucie, FL
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Senior Member

On Mon, 29 Mar 2010 17:48:37 -0600 Bryan Hayes <bhayes@byu.net> writes:
> I had a few questions regarding the GMC water heaters that I hope
> someone
> can answer.
>
> * How many gallons does the side bathroom water heater hold?

Seems to me it is 6 gallons

> * When it's running on electric, how many minutes of shower time can
> you get?
I've never measured it but it always got two showers before it would
cool. We rarely had to turn it on due to the
engine heat exchanger. Of course when dry camping we would take 'camper's
showers...i.e., turn on the water-get wet, turn off the water...soap
up...turn on the water and rinse.

> * How long does it take to recover?

Can't say I know that-I never thought about.

> * How does it compare to the 6-gallon LP water heaters found in most
> RVs?

I have no experience with propane heaters but prefer the electric one as
it is quiet, safer, and no need for another hole and ugly louver in the
side of the coach.
>
>
David Lee Greenberg
Port St Lucie, FL
Dedicated to the Preservation of the Classic GMC Motorhome
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Dave Greenberg
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Re: [GMCnet] Water heater questions [message #78509 is a reply to message #78470] Mon, 29 March 2010 21:01 Go to previous messageGo to next message
Tom Lins is currently offline  Tom Lins   United States
Messages: 372
Registered: February 2004
Location: St Augustine, FL
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Senior Member
Bryan Hayes wrote on Mon, 29 March 2010 19:48

I had a few questions regarding the GMC water heaters that I hope someone
can answer.

* How many gallons does the side bathroom water heater hold?
* When it's running on electric, how many minutes of shower time can you
get?
* How long does it take to recover?
* How does it compare to the 6-gallon LP water heaters found in most RVs?

I've noticed that the rear-bath Coachmen Royales appear to have typical LP
water heaters, while the straight GMCs have the electric/engine coolant
water heaters.

Thanks!

Bryan
No GMC yet
Salt Lake City, UT
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-6 gallons
-Never really timed it
-Specs say 6 gallons per hour so if you use it all 1 hour
-10 gallon in my SOB does better but that is also much bigger so it is not a good comparison

Your observations about the different types are accurate.

Having said that we have never run out of hot water but when we use the GMC we do like Dave does and do campers showers.


Tom Lins
St Augustine, FL
77 GM Rear Twin, Dry Bath, 455, Aluminum Radiator Quad-Bag Suspension Solar Panel
Manuals on DVD
YOUTUBE Channel: GMC Dealer Training Tapes
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Re: [GMCnet] Water heater questions [message #78515 is a reply to message #78470] Mon, 29 March 2010 21:18 Go to previous messageGo to next message
GMCWiperMan is currently offline  GMCWiperMan   United States
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Registered: December 2007
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Senior Member
Bryan,

Re: Coachmen water heaters: Every one I've seen has had the Atwood 6 gallon
propane heater WITH engine heat loop. That's a readily available option,
even today, and is noting more than a simple loop of aluminum tubing welded
on the outside of the aluminum 6 gallon tank. Many of them (including mine)
have an aftermarket electric heating element installed in the drain plug
location. It's only 600 W. or so, but with the engine heat loop, it's
seldom necessary to light the propane for a stop of less than 24 hours.

Ken H.


On Mon, Mar 29, 2010 at 7:48 PM, Bryan Hayes <bhayes@byu.net> wrote:

> I had a few questions regarding the GMC water heaters that I hope someone
> can answer.
> ...
> I've noticed that the rear-bath Coachmen Royales appear to have typical LP
> water heaters, while the straight GMCs have the electric/engine coolant
> water heaters.
>
>
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Re: [GMCnet] Water heater questions [message #78520 is a reply to message #78470] Mon, 29 March 2010 22:06 Go to previous messageGo to next message
idrob is currently offline  idrob   United States
Messages: 645
Registered: January 2005
Location: Central Idaho
Karma: 0
Senior Member
Bryan Hayes wrote on Mon, 29 March 2010 16:48

I had a few questions regarding the GMC water heaters that I hope someone
can answer.

* How many gallons does the side bathroom water heater hold?
* When it's running on electric, how many minutes of shower time can you
get?
* How long does it take to recover?
* How does it compare to the 6-gallon LP water heaters found in most RVs?

Thanks!

Bryan
No GMC yet
Salt Lake City, UT




1. 6 gallons
2. Depends on how hot the water heater is set, and how cold the mix down water is.
3. Recovery with the original 1000 watt heater was in the range of half hour, if the tank was completely drained. This also depends on the incoming water temp. Many have put a 1500 watt element in the heater, which makes it considerably faster. In mine, I had put a 2000 watt element, and the recovery time was in the 15 minute range, but one had to monitor the electric use more carefully. I did it to reduce generator run time.
4. With the 1000 watt original element the heating capacity is 3410 btuh. Most propane water heaters with efficiency losses, are about 5000 to 6000 btuh, so the original heating element is a bit slower. With a larger element it can be as fast or faster.

In general the electric water heater is not a problem vs. a propane one.


Rob Allen
former owner of '76 x-PB
Re: [GMCnet] Water heater questions [message #78542 is a reply to message #78470] Tue, 30 March 2010 02:37 Go to previous messageGo to next message
Mr ERFisher is currently offline  Mr ERFisher   United States
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Registered: August 2005
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Senior Member
and ,

the new way by Ray, that will become standard
http://gmcmotorhome.info/living#DEMAND

gene


I had a few questions regarding the GMC water heaters that I hope someone
> can answer.
>


--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
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Re: [GMCnet] Water heater questions [message #78579 is a reply to message #78470] Tue, 30 March 2010 11:13 Go to previous messageGo to next message
Duce Apocalypse is currently offline  Duce Apocalypse   United States
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Location: Los angeles
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having showered in my GMC extensively, took about an hour to make nice hot water out of 50* water.

this was good for a 7-10 minute shower pausing intermittently to scrub up before the water was luke warm.

recovery was about 30-45 minute. and I still have the stock unit.


was thinking of getting on of those ebay gas tankless units. some of the guys here have installd them behind their fridge and they seem to work great, and will never run out of hot water.

I do likethe idea of using a 2kw element to heat the standing tank tho, that seems like it would have a very fast recovery time...



73 Canyon Lands, (a.k.a. The Yellow Submarine) West Los Angeles CA
Re: [GMCnet] Water heater questions [message #78649 is a reply to message #78579] Tue, 30 March 2010 21:58 Go to previous messageGo to next message
bhayes is currently offline  bhayes   United States
Messages: 263
Registered: March 2010
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Senior Member
Thanks for the responses, everyone. Very helpful information.

I like the idea of the tankless water heater. It certainly would be nice
when parked at a campground when we're not worried about running out of
water or filling up the holding tank.

Where can I find the 2KW heating element?

Bryan Hayes
No GMC yet
Salt Lake City, UT

On Tue, Mar 30, 2010 at 10:13 AM, Shan Rose <defconfx@gmail.com> wrote:

>
>
> having showered in my GMC extensively, took about an hour to make nice hot
> water out of 50* water.
>
> this was good for a 7-10 minute shower pausing intermittently to scrub up
> before the water was luke warm.
>
> recovery was about 30-45 minute. and I still have the stock unit.
>
>
> was thinking of getting on of those ebay gas tankless units. some of the
> guys here have installd them behind their fridge and they seem to work
> great, and will never run out of hot water.
>
> I do likethe idea of using a 2kw element to heat the standing tank tho,
> that seems like it would have a very fast recovery time...
>
>
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Bryan Hayes
'76 Eleganza II
Salt Lake City, Utah
Re: [GMCnet] Water heater questions [message #78661 is a reply to message #78649] Tue, 30 March 2010 23:20 Go to previous message
idrob is currently offline  idrob   United States
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Location: Central Idaho
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Bryan Hayes wrote on Tue, 30 March 2010 19:58

Thanks for the responses, everyone. Very helpful information.

Where can I find the 2KW heating element?

Bryan Hayes
No GMC yet
Salt Lake City, UT




They are not common, but I found mine at a local (not big box) lumberyard/home center. 120 volts, 2000 watts. My 76 had a #12 wire to the water heater, so It would support the 2000 watt heater, with a 20 amp breaker. You may have to be a bit careful of what else you are operating at the same time when plugged into shore power, if it is a 30 amp hookup.


Rob Allen
former owner of '76 x-PB
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