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Topic: Aquahot Mixing Valve (Read 1053 times) previous topic - next topic

Aquahot Mixing Valve

 After taking many lukewarm showers, I decide or my wife decided that I need to look into the problem. My findings are 155 t'stat instead of factory 190 for diesel side so cut in will be around 115.
Electric side was 169 instead of 198 so cut in will be around 130 or so. Mixing valve was screwed all the way to mix max cold. Makes a menu of cold shower.
  I replace both t'stats with generic limit switches from local HVAC parts house for a mild 6 bucks each verses 36 & 31. I then remove
the burner to find my diesel smell in the basement, a small drip. It would evaporate the fuel before it would go anywhere. But lots of good smell because the aguahot is always hot.
  I then exercise the stuck mixing valve. If you move the valve a little at a time each way with water running it broke loose. Yea!
I then set it to max hot. I now have very hot shower. And the diesel smell is disapating. I might end up having to adjust mixing valve again in the summer with warm cold water. We'll see. Thanks for all of the help on here.
99 U320 40
97 Jeep wrangler toad
Now full time 8 months
Starting a new brick and wood home
Chattanooga, Tn

Re: Aquahot Mixing Valve

Reply #1 –
Where is that mixing valve located?
John & Genni Kerbs
ex 1993 U280 40'
1997 U320 40"
Build #5171
Engine: M11 450
Floor plan: walk thru bath

Re: Aquahot Mixing Valve

Reply #2 –
Alan,

A properly operating Webasto burner does not drip fuel, period.  Check fuel line and connections at fuel banjos, fuel line connections at fuel pump and fuel pump shaft seal.  A fuel leak can be a fire hazard.

John,

The mixing valve is located, on your heater, in the center of the pan under the Webasto burner.  It has three pipes coming into the mixing or tempering valve -- cold water in, hot water in and tempered water out to the faucets.
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: Aquahot Mixing Valve

Reply #3 –
Quote from: Rudy –
The mixing valve is located, on your heater, in the center of the pan under the Webasto burner.  It has three pipes coming into the mixing or tempering valve -- cold water in, hot water in and tempered water out to the faucets.

I have heard that aqua hot restricts the hot water flow to get the continuous flow rating.

Can I add more hot water output by adjusting the valve if I do not care about the constant flow?

My shower valve is fairly sensitive and way to the hot side so get a normal temp mix.

Thanks bob
"Riding and rejoicing"
Bob
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: Aquahot Mixing Valve

Reply #4 –
Alan

The thermostats that control the Aqua-Hot are made just for Aqua-Hot.  The thermostat that you purchased locally, may or may not meet proper specifications.

The mixing valve has internal parts that control the water temperature by mixing very hot water heated by the Aqua-Hot with incoming cold water to send constant warm water to the coach.  If you get inconsistent water temperatures, you may have to replace the internal parts.  I always set mixing valve to send 120 degree water to the coach.  Any hotter and you run the risk of someone getting scalded. 

If the knob is stuck, it is common for the knob on the mixing valve to spin on the shaft.  Verify that the shaft on the mixing valve is turning.  Not a very robust knob.

- Roger Berke -
http://www.Forum.RVHYD.com

Re: Aquahot Mixing Valve

Reply #5 –
Bob

No restriction but the 115 to 120 degree tempered water would need little extra cold water so knob way over to hot side.
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: Aquahot Mixing Valve

Reply #6 –
Quote from: Rudy –
Bob

No restriction but the 115 to 120 degree tempered water would need little extra cold water so knob way over to hot side.

The old propane Atwoods had two different sets of thermostats.  If no children were to use the coach I used to put the higher limit set in coaches.  You had hotter water to dilute with more cold for a little extra capacity.

Does the valve and the system in my 97 itself have enough adjustment in it to put out unlimited hot water at 125-130?

What exact unit is in my 1997?

Thanks. Your valve works great.  Buddy cursed Foretravel for having the control knob face away from the service opening
"Riding and rejoicing"
Bob
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: Aquahot Mixing Valve

Reply #7 –
Bob,

The Aqua Hot heater is rated to provide a 55 degree temperature rise at a gallon and half per minute flow rate.  So where ever you set the tempering valve, you can only expect an output temp 55 degrees above the incoming temp.

If you want 130 degree water coming out of the Aqua Hot, you need 75 degree incoming water or really slow down the flow to allow the water in the fresh water coil much more time to pick up heat.

You get the max temp from the tempering/mixing valve by turning the knob all the way out admitting the minimum amount of cold water for tempering purposes.

Hope this helps you.
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: Aquahot Mixing Valve

Reply #8 –
Ok I'm getting slammed for using after market protects. I worked in the a/c world for a decade plus. It really is not rocket science
With this issue. I chose after market with a little larger cut in, cut out tollarance, for a lot of savings. My heater now works great. As for the mixing valve, I have not changed anything other than the temp flow difference. Yes if you can not adjust the temp the mix valve would be bad. Mine is not. I love this forum. I have learned extensive knowledge from it. I just want to extend the knowledge.
Thanks. Alan
99 U320 40
97 Jeep wrangler toad
Now full time 8 months
Starting a new brick and wood home
Chattanooga, Tn

Re: Aquahot Mixing Valve

Reply #9 –
Alan,

Have you checked on the fuel leak?

What model Aqua Hot do you have and what year and model Foretravel do you have?

Over time, the newer models of heaters use different thermostats with different mounting methods.  What mounts on a 1997 Foretravel Aqua Hot heater will not mount on a 2010 Foretravel Aqua Hot heater as a plug and play.  But if the mounting method did not match the old thermostat, an inventive person could certainly come up with a mounting method for the thermostat of his choice that would work just fine.

Your heater model and year would be interesting to know.  You might consider a note in the signature line that is used by many members to share their coaches info.

I forgot to say welcome to the forum as I see you are currently a newbie.  Hope to see you here more as extensive A/C knowledge is a benefit to all of us.

Good for you on the success of your thermostat and freeing up the mixing valve project.  I love to conserve funds when working on my coach too.
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: Aquahot Mixing Valve

Reply #10 –
Alan

My intent here is not to offend but to share my knowledge of Aqua-Hot systems.

- Roger -
Forum.RVHYD.com

Re: Aquahot Mixing Valve

Reply #11 –
I had a very bad day at work yesterday and I got a little  protective of myself. My apologies to all. This forum is full of so much knowledge both staying factory and slight changes to dramatic changes.
  I did fix the leak. It was the supply line to the burner. The end was dry rotted and had a crack allowing a small drip. The rest of the line was very good so I cut it and put a hose clamp on it.
  While I had the burner out I cleaned it. It was very clean. Signs of a clean burning unit.
  Oh yea I have a 431/12 unit. I have down loaded the service manual of the aguahot web site. A lot of very good info. The difference between factory t'stat (limit switch) and generic is the differential between cut in and cut out, or on off. Aguahot is 25 and generic is 35. Both are a bimetal disc that is mass produced so they neither are very accurate. Only a 10 to 15% tollerence.
  Thanks again to all.
99 U320 40
97 Jeep wrangler toad
Now full time 8 months
Starting a new brick and wood home
Chattanooga, Tn

Re: Aquahot Mixing Valve

Reply #12 –
Roger,

Will you be in Q in Jan?

best, paul
1999 U320 40' 1200 watts on roof. 12cf AC/DC Cold plate fridge/freezer. VMS 240 CL Honda Element
 

Re: Aquahot Mixing Valve

Reply #13 –
Quote
Roger,

Will you be in Q in Jan?

Paul

I am not going to Quartzsite this year.  I plan to spend the winter in a different location.  Watch for announcement soon on my Forum.

If you are looking for Aqua-Hot service, there will be a couple other guys there. 

- Roger -
Forum.RVHYD.com