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Topic: Aqua Hot hot water (Read 2287 times) previous topic - next topic

Aqua Hot hot water

We have a 2001 U320 and the hot water from shower, Kitchen and bath various from 79 to 81 degrees. It seems a little on the cool side to me as I need to run the shower using hot only and never have to mix in from cold to cool it down. I had it serviced 2 years ago, exercise it monthly and it runs smooth and clear at the exhaust.
Is there a "normal" temperature of hot it should be putting out?
Jon Ohman
2001 U320 36'
Build #5809

Re: Aqua Hot hot water

Reply #1
There is a mixer valve with a thermal device that regulates the domestic hot water.  Seems to me like ours is right under the pump and has a red handle.  We had no hot water and had to replace it.  Rudy will probably chime in on this one.  He helped me with ours. 
Rick & Rhonda
2003 U320 4220  Build #6199
Was
91 36' GV 300 Caterpillar, 92 40' U280 300 Cummins, 97 36' U295 300 Cummins, 2002
U320 450 Cummins
(Guess we're hooked)

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Re: Aqua Hot hot water

Reply #2
We had the same problem and replaced the mixing (tempering) valve and that fixed it. The valve is located under the fuel pump/blower assembly. Buy a new valve assembly and just transfer the guts to the old valve body. Pretty easy DIY project.

Steve
Steve & Sandy
2003 U320 4220 WCDS, build#6160
Motorcade #17794
USMC '67-'71


Re: Aqua Hot hot water

Reply #4
Could it be the shower valve itself?
Forest & Cindy Olivier
1987 log cabin
2011 Roadtrek C210P
no longer 1999 36' U320 build #5522
2013 Rzr 570 & 2018 Ranger XP1000
2006 Lexus GX470
2011 Tahoe LT 4x4
Previous 1998 45' 2 slide Newell, 1993 39' Newell

Re: Aqua Hot hot water

Reply #5
Hot water temp at all hot water facuets, not just shower, should be 115 to 120 degrees and steady at that temp.  SteveB is right that the most likely solution is new guts for the tempering valve.

To check this out, heat the heater up to temperture.  When the diesel burner cycles off, heater is up to temp.  Turn on a sink, not shower, hot water facuet and check the temp of the copper pipe coming from the Aqua Hot tank to the tempering valve.  This can easily be to hot to hold onto.  Then check the temp of the hot water leaving the heater going up into the coach.  If first line stays real hot and water to coach cools off, replace the tempering valve guts.

If sink stays properly hot, then shower faucet is suspect.

To replace the guts, order a new vavle.  Remove the burner from the heater revealing the tempering vavle.  Loosen the knurel nut holding the old guts in the tempering vavle.  Remove new guts from new valve and insert into tempering valve.  Tighten knurel nut, replace burner and you are done.

Easier said than done but not to hard a task.
Rudy Legett
2003 U320 4010 ISM 450 hp
2001 U320 4220 ISM 450 hp
1995 U320 M11 400 hp
1990 Granvilla 300 hp 3208T
Aqua Hot Service Houston and Southeast Texas

Re: Aqua Hot hot water

Reply #6
A tip I learned some time ago was to always use the water in your fresh water tank when you need hot water and the ambient temperature is cold. The water coming out of the ground can be close to freezing and I believe the max temp rise for the Aqua Hot is something like 50 degrees F. So, if the incoming water is 35 degrees you will probably only see 85 degree water at the faucet at full flow. If the water in your fresh water tank is 50 degrees then you will have 100+ degree water at the faucet because you are heating warmer water and mixing it with warmer water as well.
My numbers are probably not exact but I think you get my point.

Steve
Steve & Sandy
2003 U320 4220 WCDS, build#6160
Motorcade #17794
USMC '67-'71

Re: Aqua Hot hot water

Reply #7
Thanks all for your replys/information.. Now the problem has been identified.
FYI, I was on tank water and Aqua Hot had run a full cycle and at max.
I'll get it fixed and look forward to a "hot" shower.
Great information when you need it, great forum of Foretravelers.
Jon Ohman
2001 U320 36'
Build #5809

Re: Aqua Hot hot water

Reply #8
One tip, make a mark on the tempering valve knob before you adjust or replace the guts.  That way you know where to set it when you're done.
Forest & Cindy Olivier
1987 log cabin
2011 Roadtrek C210P
no longer 1999 36' U320 build #5522
2013 Rzr 570 & 2018 Ranger XP1000
2006 Lexus GX470
2011 Tahoe LT 4x4
Previous 1998 45' 2 slide Newell, 1993 39' Newell

Re: Aqua Hot hot water

Reply #9
Some brands like Beaver and Country Coach built their own recirculating hot water plants using Webasto burners.

Why?  Because of the 1.5 gallon per minute continuous hot water output.  Not enough for some customers.

Beaver Marquis had four zone heating and needed to have the ability to fill a jacuzzi bath tub in their Orlov floor plan.

No way an aqua hot had the output.  Plus more money to buy a aquahot versus make you own
"Riding and rejoicing"
Bob & Susan
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Aqua Hot hot water

Reply #10
Our older FTs are not limited to 1.5 gal per minute output.
From the user manual for the AHE-100-02S installed in my coach (or a later version) and most U320s.  Unlimited hot water.

Hot Water
2.3 Using the Domestic Hot Water System
Aqua-Hot Motor Coach Heating System Owner's Manual 05/02
Page 2-3

SECTION 2: OPERATING INSTRUCTIONS
When the Aqua-Hot is at operating temperature, the domestic water is automatically heated as it is being used. Because the Aqua-Hot does not store any hot water simply open any hot water faucet and a continuous supply of domestic hot water will be present within a few seconds. This hot water feature is continuous and is accomplished by the Aqua-Hot's Mixer Valve and Intergal Domestic Hot Water Heating System. Please note that the Diesel-Burner Control Switch must be ON to get an unlimited supply of hot water (i.e. during showers).


We have no trouble doing 5 minute or more showers on 120v alone.

Anyone can misread and distort facts into anything they want. 

Re: Aqua Hot hot water

Reply #11
The aqua hots temperature rise of 55 degrees over the units water inlet  temp maxes out at 1.5 gallons per minute flow rate. 

Past the 1.5 gpm rate the 55 degree temp rise decreases.

Only so many BTU's input in a aqua hot system.  Not unlimited heat.

Webasto burner was separately purchased by the other mentioned brands to give more gpm flow or a hydro hot system.

Turn on all your faucets on hot and the shower and after the coils run out of hot water the temp will start to fall.

Beavers used a Parr water pump capable of much higher water flow than a normal rv water pump. 

And used a residential high flow shower head in most models
"Riding and rejoicing"
Bob & Susan
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Aqua Hot hot water

Reply #12
Here you go.
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Aqua Hot hot water

Reply #13
Here's what the 'guts' of the tempering valve look like.
Dick, '03 U320 40' Tag, 2 slides, Coach #6075
Full Timers
2009 Honda CR-V

Re: Aqua Hot hot water

Reply #14
Someone posted the Aqua hot bearing numbers and I can't seem to find them--Could I get a re-posting
Thanks
Chris
1999 U 320 DGFE
Build Number 5523
Chris & Elka Lang
In the field, Lonoke AR

Re: Aqua Hot hot water

Reply #15
Chris,

608RS
I buy SKF rather than the cheaper skate board bearings that you will find.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Aqua Hot hot water

Reply #16
Before replacing the tempering valve, try exercising it.  Make sure you mark the current position of the valve knob.  Rotate the knob its full range back and forth a couple times, then try Rudy's temperature test again.
Regards,
Brett

'99 42' Foretravel Xtreme
'14 Brown Motorsports Stacker
'05 Chevy SSR
'02 BMW R1150R

Re: Aqua Hot hot water

Reply #17
Our older FTs are not limited to 1.5 gal per minute.

From the user manual for the AHE-100-02S installed in my coach (or a later version) and most U320s.  Unlimited hot water.

We have no trouble doing 5 minute or more showers on 120v alone.

Anyone can misread and distort facts into anything they want. 

Bob is not the one distorting the facts here.

Roger Berke & Rudy have both stated that the Aqua-Hot units in our older coaches are rated for a 55 degree temperature rise at 1.5 GPM. Running the numbers confirms that the diesel burner doesn't suppy enough energy to heat incoming very cold water (such as coming from a city water tap) to 120 degrees at flow rates significantly above 1.5 GPM. Incoming water at moderate temperature and with one shower flowing is no problem, but the Aqua-Hot simply cannot continuously suppy hot water at higher flow rates under all circumstances.
David and Carolyn Osborn
1995 U320C SE 40' Build 4726 Feb 1995
FMCA 147762
Motorcade 17186

Re: Aqua Hot hot water

Reply #18
Bob is not the one distorting the facts here.

Roger Berke & Rudy have both stated that the Aqua-Hot units in our older coaches are rated for a 55 degree temperature rise at 1.5 GPM. Running the numbers confirms that the diesel burner doesn't suppy enough energy to heat incoming very cold water (such as coming from a city water tap) to 120 degrees at flow rates significantly above 1.5 GPM. Incoming water at moderate temperature and with one shower flowing is no problem, but the Aqua-Hot simply cannot continuously suppy hot water at higher flow rates under all circumstances.

Half the facts don't make a complete conclusion.

Yes you can pick and choose your facts any way you want to make whatever case you want.  So if you are connecting to very cold city water or well water you may not get a continuous supply of 120 degree water.  If you are using water out of your tank that has been sitting there for a while you probably will.  If you are parked somewhere in sub freezing weather maybe not.  Maybe you have un-wisely selected a 3 gal per minute shower head, probably not.

Deep well water might be 40-45°.  Our well water in MN is 45° +/- 1 or 2 degrees all year round.  They are commonly used in geothermal heating and cooling systems. Most city water is amost always warmer than that.  So 55° increase is going to be at least 95° at 1.5 gal per minute.  You are probably not going to be showering with all hot water so some mixing is going on which means you are not using 1.5 gal per min or hot water but maybe 1 gal per min or maybe less in which case the temp rise will be greater. Which means you will use less hot water giving you even more temp increase.

You can use your AquaHot anyway you want and perhaps find a situation where you can reach its limit.  CaFlashBob was implying that the AquaHot in our Foretravels is inadequate.  Out of context this is misleading to someone looking at a Foretravel with an AquaHot when for almost everyone with an AquaHot in almost every circumstance it provides continuous hot water for the way we use it. 


Re: Aqua Hot hot water

Reply #19

Half the facts don't make a complete conclusion.

Yes you can pick and choose your facts any way you want to make whatever case you want.


This is exactly what you did when you gave the impression that our Aqua-Hot units will continuously supply well over 1.5 GPM of hot water under all circumstances. Bob was correct in stating that their specifications do not state that.
David and Carolyn Osborn
1995 U320C SE 40' Build 4726 Feb 1995
FMCA 147762
Motorcade 17186

Re: Aqua Hot hot water

Reply #20
I spent a conserable portion of my Foretravel manager years long ago discussing the various defrugalities of the systems installed in the owners  coaches.  We all learned  together.  No harm.  No foul. 

The details is where the rubber meets to road as it is.

Having lived with the way back when early rv systems like three way Dometic's and six gallon water heaters and being a winter dry camper if required the finite details on exactly how the systems work on our coach is important.

The idea that it is optimized as equipped for four season dry camping with backups for almost every system in it is important to us in shaky town.

Not so important to most.  They are used to power poles or run the gen and nice weather.


"Riding and rejoicing"
Bob & Susan
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Aqua Hot hot water

Reply #21
Quote from Rudy about 10 months ago.
The water heating spec for the Aqua Hot heater is 55 degree temp rise at 1.5 gal per minute flow.  In cold climes, you may be ingesting really cold ground water such as perhaps 40 degrees.  Add 55 to that and you are not happy but the heater is working correctly.

So one can fill the onboard fresh water tank, turn the basement thermostat up to full hot and leave overnight.  Next morning you have warm enough water via the fresh water pump to have a nice shower.  You can possibly slow the water flow down giving it more time to pick up heat as long as you enjoy the show flow.

Keep the fresh water tank topped off as adding 20 gallons of cold to 80 that is warm works better than the other way around.  Electric is not rated to provide hot water for showers.  You always need the diesel burner and electric element if plugged in.  Diesel burner is needed in temps below 45 degrees for interior heating as well as hot water.

There could be a mixing valve issue as mentioned also.  To test, turn hot water on till it is just warm or cool.  Place your hand on the pipe from the tank to the mixing valve.  If real hot, mixing valve.  If not real hot, incoming water temp and/or to fast water flow.  You must be at the heater reaching under or around the burner to do this test.

Hope this helps.
More...Like Quote
Rudy Legett
1995 U320 M11 400 hp
Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.

Re: Aqua Hot hot water

Reply #22

Quote from Rudy about 10 months ago.
The water heating spec for the Aqua Hot heater is 55 degree temp rise at 1.5 gal per minute flow.  In cold climes, you may be ingesting really cold ground water such as perhaps 40 degrees.  Add 55 to that and you are not happy but the heater is working correctly.


Exactly! The Aqua-Hot models in our older coaches are great units but there are real-world conditions where they cannot continuously supply the hot water needed for a comfortable shower.

Unfortunately for those who prefer insults over facts and physics even great systems such as our Aqua-Hots do have their limitations!
David and Carolyn Osborn
1995 U320C SE 40' Build 4726 Feb 1995
FMCA 147762
Motorcade 17186

Re: Aqua Hot hot water

Reply #23
The Aqua Hots in the newer coaches are smaller and only have 2 zones. Our older coaches have more hot water than they do.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Aqua Hot hot water

Reply #24
I'd like to bump this as cold weather is upon some of us.

It's a good idea to use water from the fresh water tank rather than much colder water from the campground if you like hot showers.

I find this works with my 10 gallon propane water as well.
Tom Lang K6PG (originally  KC6UEC)
and Diane Lang
2003 38 U295 build 6209
2016 Jeep Grand Cherokee Summit Ecodiesel
still have tow-ready 2006 Acura MDX 
Temple City, California
Motorcade 16681 California Chapter President
SKP 16663 member of SKP Park of the Sierra, Coarsegold California
FMCA F071251
Retired electrical and electronic engineer