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Water heater question

I have a '92 40 ft. U300 and am planning to change the water heater.  It currently has a 6 gal. propane heater.  I have two questions:
1. Will the space accommodate a 10 gal. water heater?
2. Is the water heater storage bay already wired for electricity which would allow me to put a propane and electric water heater in rather than just another propane heater?
Thanks in advance for your help,
Kearn
Kearn
'92 U300 40 ft.  WTBI  6V-92  #4130
GMC Yukon toad
'08 Casita Spirit Deluxe 17ft

Re: Water heater question

Reply #1 –
Just a thought.....consider the tankless system.  We have some friends put one of those in a trailer, it fit better than trying to convert to the 10 gallon tank system.

mike
Mike
2001 U320 4010 Build 5878 (Gus)
Wrangle Unlimited Toad
Nacogdoches

Re: Water heater question

Reply #2 –
We recommend buying the model with electric & propane. You will be surprised how straight forward it is to connect to electric. And the new heater will work on propane just fine until you or someone else completes the 120-volt wiring.

You are probably not pre-wired, but a nearby electric outlet COULD be used, by cutting off the female end of an appropriate extension cord and connecting it to the heater. (That's what we did, as our coach was built with just a propane heater and not pre-wired for electric heater.) Or you could run a new Romex cable to the circuit breaker box.

It will be up to you to check out the limitations of your heater mounting area to see if the dimensions of a 10 gallon could fit, as different coaches have their heaters in different places, mounted in different ways.

The two RV water heater manufacturers (Surburban & Atwood) setup their units differently, so you may want to replace same manufacturer. Or one or the other's 10 gallon may fit your 6-gallon space better.

Re: Water heater question

Reply #3 –
Be sure to check-- you likely need the model that has MOTOR-AID and propane, with electric being a third choice of heat source.  Easy to tell-- if you have heater hoses going to the back of the water heater along with the potable water hoses, it has motor-aid.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Water heater question

Reply #4 –
Welcome Kearn,
I have a '91 U300 which might be different in regards to the water heater (but not likely).
To answer your questions (to the best of my understanding):

1.  Yes there is space there to accommodate a 10 gallon unit but only with some modifications: 
a)  The heaters mount with a flange on all four sides.  Foretravel has 1-1/2" square steel tubing on the perimeter to accommodate the mounting.  Ten gallon units differ only in one dimension: height.  This obviously means the steel frame would need to be extended down.
b) The face of the water heater is actually outside the sealing area of the door which is necessary for the safety temperature-pressure relief valve, the air supply and exhaust.  As such the bulb seal is attached to an aluminum section ("C" shaped with one long leg) that mounts to the left and bottom of the heater.  This aluminum section would need to extended down as well with the steel tubing.  I believe this aluminum section is only available from Foretravel and it used to hold the bulb seal on all of your basement compartments.
c)  The also the water accumulator tank (blue) that's located below the water heater along with the water pump.  Consider moving the tank to another location.  I moved mine to under the kitchen sink for ease of access to the water pump and I still have a 6 gal water heater.
d)  The interior of the compartment door is cut out on the inside to accommodate the heater.  This would need be cut out more the for the larger water heater and you will need to mount the larger face panel to the outside of the door of course.

2.  Yes.  Being a U300 your water heater should be 3-way:  Propane, 120VAC electric and "motor aid" (meaning the heater hose from the engine passes through a tube in the water heater helping it to heat while you are driving).  There should be a blue handled water valve below the heater.  It is there to turn off the motor aid incase you want all available heat to go to the dash.  At the base of the bed there should be an illuminated red switch labeled "water heater" that supply's power to the rear of the heater where the electric element, thermostat and on/off switch are at.  You can reach the back of the heater by reaching up under or there should be an access hole through the storage compartment on the side - neither is very convenient.  Any real work on the 120VAC part of the heater generally requires removal of the heater - which is a quite as task as well; but this made easier if SS braided flex hoses are added so the water connections can be reached with heater pulled out with the face of the unit resting on small table or stool.

I have a 6 gallon unit and probably would have done the mods to convert to 10 gallon but when the old one went out it I was traveling and just didn't have the time or tools to do it.  If you want more hot water capacity and you are usually hooked up to electricity consider adding a small residential (what they call "point of use") heater in the 5-10 gallon range.  I use a 10 gallon unit and it is plumbed "before" the OEM unit.

John Fitzgerald
1991 U300 (SAI) Side Aisle Island Bed 40'
Detroit 6V92 with Allison Retarder
Meridian (Boise), Idaho

Re: Water heater question

Reply #5 –
I had the same experience as JohnFitz and made the same decision. Going to the 10 gal would have required cutting out and rewelding the 1.5" steel tubing and I wasn't sure if the unit would fit into the same cutout in the bay door. Just stayed with the 6 gallon.

Also something to be aware of the new units from Atwood use a solenoid to switch on the 110v so just hooking up the 110v doesn't work. Atwood provides a new panel with a propane and 110v switch but it is white and looks pretty ugly next to the black Foretravel switches. I read where others have just wired the 110v to the propane switch so that 110v is on anytime the propane is on but only when 110v is available. So you would be using propane all the time but with the 110v the propane would be running much less often. Hope that makes sense!

see ya
ken
The selected media item is not currently available.ken & dori hathaway & Big Agnes
🍺1992 U300 GrandVilla WTBI #4150 FOT FBP 2011
✨6V-92TA DDEC Parlor Coach 350HP Series 92
🏁2011 Nissan XTerra Pro-4X

Re: Water heater question

Reply #6 –
To add to what Ken just said.  I too replaced my old Atwood, with a new one that also had the 120 volt element like my OEM unit.  As Ken has said, the wiring is slightly different.  There is now a relay on the back of the water heater controlled by the new white switch.  I did not like the plastic switch.  Don Fara was at the warehouse and showed what he had done installing his new unit.  Per his suggestion I installed a simple toggle switch on the water heater unit outside in the existing wires.  That allows me to control when the propane is used.  The sink cabinet switch is used now to "turn on the water heater control".  The bed platform 120v switch stays on all the time now, and to make the propane option work, I have to open the bay door and switch the toggle on for the gas to work.
Dave Cobb
Buckhorn Lake Resort The Club, #6202, Kerrville TX
check the map.  I do rent it out when I am traveling!
2001, U320, 36' #5887, in Kerrville, FT Club #17006, (7/23 to present)
2024 Jeep Grand Cherokee L, Summit, white
EX: 98 U295, 36' #5219, (mid door), (4/13-10/23)
EX: 93 U225, 36' (4/11 to 4/13)

Re: Water heater question

Reply #7 –
RE temperature-pressure valve to not floor the interior of the compartment

We ran a hose from temp-press relief valve through the bottom of bay, to eliminate water in bay, if & when valve opens.

Re: Water heater question

Reply #8 –
It is easy to wire the new Atwood water heaters to just use the light switch at the base of the bed. You just tie the propane control and the electric element control wires at the water heater together and connect them to the existing switch wire coming from the kitchen. EDIT: The orange wire is for the propane relay and the white wire is for the relay that controls 120VAC heating element. Then the electric element works whenever the bedroom switch is lit, but the propane will always be engaged when you have the kitchen control switch on. If you want them independent, you need to run one wire from the water heater area to the kitchen and add a switch. Edit: If you want the lockout light to function as shown in the manual, you need to run a wire for that too. As Ken said, the Atwood supplied switch is ugly! I repurposed the antenna booster switch and swapped out the red LED for a green one from RS, ran the wire and added the switch next to the existing water pump and water heater switch.

Don
Quote from: kenhat –

...Also something to be aware of the new units from Atwood use a solenoid to switch on the 110v so just hooking up the 110v doesn't work. Atwood provides a new panel with a propane and 110v switch but it is white and looks pretty ugly next to the black Foretravel switches. I read where others have just wired the 110v to the propane switch so that 110v is on anytime the propane is on but only when 110v is available. So you would be using propane all the time but with the 110v the propane would be running much less often. Hope that makes sense!

see ya
ken
The selected media item is not currently available.
Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
Freedom is NOT "just another word for nothing left to lose"... with apologies to Kris Kristofferson

Re: Water heater question

Reply #9 –
We think the Atwood hot water panel is just fine and gives us maximum control over electric & gas heating. Individual switches light up if gas &/or is turned on.

We added small LED lights that turn on when gas or electric is activated by thermostat and elements are heating. When these LEDs are off, hot water is ready for use.

Because the electric relay is behind the hot water heater, which would require a tank removal to service the relay, we moved the relay to an accessible place and ran a power cable from relay to the backside heating element.

We do not have engine cooling system motor-heat feature.

Re: Water heater question

Reply #10 –
I have no doubt that the Atwood panel provides the needed functionality, I just didn't want to modify the cabinet for something that looked aftermarket to me. Also, I just happened to have the antenna booster switch which even had an LED mounted in it. I wired the lockout lamp wire to the red LED on the old switch, which had both green and red LED's. I use the original switch for electric and the repurposed switch for the gas. I ran two 18 gage wires, one for the propane relay and one for the lockout lamp. It was easy for me because while I had the wet bay ripped apart, I ran some conduit and misc wires of different gages and colors from both sides of the wet bay to the front of the storage compartment near the relay panel (also up to the front of the coach, that part was not so easy!. . That conduit is going to come in handy for me to wire in the new shore power reel when it comes tomorrow ;D.

By the way, the lockout lamp wire is blue, and the electric is white and LP gas is an orange wire. I was in error on the wire colors in my previous post and will edit it to correct it.
Don
Quote from: Barry & Cindy –
We think the Atwood hot water panel is just fine and gives us maximum control over electric & gas heating. Individual switches light up if gas &/or is turned on.
The selected media item is not currently available.
Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
Freedom is NOT "just another word for nothing left to lose"... with apologies to Kris Kristofferson

Re: Water heater question

Reply #11 –
Our '93 U300 has only propane as far as I can tell. There is one line in the compartment with an old-fashioned round valve in it that so far I haven't figured out. Might that be the Motor-aide? Definitely no electric, though.

Re: Water heater question

Reply #12 –
Quote from: kb0zke –
Our '93 U300 has only propane as far as I can tell. There is one line in the compartment with an old-fashioned round valve in it that so far I haven't figured out. Might that be the Motor-aide? Definitely no electric, though.

Yes, particularly if it is on black hose it is motor-aid.  The valve is open to warm water, closed to put all the heat to the dash heater.

If you look closely, you will see two SETS of hoses-- those of the potable water AND those of the hoses connected to the engine's cooling system.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Water heater question

Reply #13 –
Correct! That is the valve that controls whether the coolant is all directed to the heater core (closed position) or shared between the heater core and the water heater. This is to improve the cockpit heater in cold conditions. There should be or used to be a label which says "close for max dash heat" or words to that effect near the valve.
Don
Quote from: kb0zke –
Our '93 U300 has only propane as far as I can tell. There is one line in the compartment with an old-fashioned round valve in it that so far I haven't figured out. Might that be the Motor-aide? Definitely no electric, though.
The selected media item is not currently available.
Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
Freedom is NOT "just another word for nothing left to lose"... with apologies to Kris Kristofferson

Re: Water heater question

Reply #14 –
I'm glad you guys taught me where that motor assist valve is. I was looking for that this winter when I was driving in an ice storm and couldn't get enough heat to the defroster even with the aux pump running. Unfortunately I don't see anyplace to plug in an electric heat element in my pump / water heater bay. I looked in back with an inspection mirror. I was considering installing a Hot Rod but it would take the rest of my life to save $100 in propane to offset the cost of the thing. Also I think maybe it's good to run the propane heater once in a while to incinerate any insects that might take up residence in there. :))  I know, I need to get one of those insect screens for my water heater, and it's on my list of stuff to buy and install soon.
Scott Cook
1991 U300 36' 6V92TA
Old Town Penobscot 16
1984 Honda VF1100C (V65 Magna)

Re: Water heater question

Reply #15 –
Scott,

You propane furnace should have a vent into the wet bay.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Water heater question

Reply #16 –
Quote from: RRadio –
I know, I need to get one of those insect screens for my water heater, and it's on my list of stuff to buy and install soon.
I used some aluminum window screen material formed around the stock vent. On a previous coach, I used a screen that I bought in a campground store. Both work to keep the mud daubers out. Based on experience with the previous coach, I can confirm that "daubers" can mess up a water heater. Based on my experience with the current coach, I can can confirm that "daubers" can trash the burner screen on a propane furnace.
J D Stevens
1997 U295 CAI 36' Build #5085
2002 Subaru Outback
Motorcade 16869
Bellville, TX

Re: Water heater question

Reply #17 –
While coach is in storage, I close cheap nylon screening in the access doors for furnace, water heater and refrigerator lower access door.

Yes, remove them before leaving in the coach/turning on appliances.

Really not concerned with insects setting up residence when I am using the appliances-- too hot in there even for them!
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Water heater question

Reply #18 –
In this thread there is a photo of the Motor Aid valve: Camping in Cold Weather-Long but hopefully useful  It's just a standard plumbing valve with two black heater hoses on each end.  I have it labeled "MOTOR ASSIST"
John Fitzgerald
1991 U300 (SAI) Side Aisle Island Bed 40'
Detroit 6V92 with Allison Retarder
Meridian (Boise), Idaho