Still learning about my new to me '01 Patriot with Hydro Hot system. Records indicate that the entire unit was replaced a year ago.
With diesel and electric on, I am able to shower without mixing any cold water with the hot. The temperature is warm, but not hot. It is tolerable, but I would like hotter water. Is there an adjustment? Or is warm water all I should expect?

Jim, the first thing to check is the outside water faucet if your coach has one. The valves must be off or it will act like a mixing valve and provide only warm water. I presume you have verified the diesel burner is operating so check this out before we go to the temperature adjustment valve. The outside faucet is the most likely culprit.

Jim, my unit has a mixing valve that can be reached from the rear access panel on the AquaHot .  My unit was running too hot and a minor adjustment of the mixing valve did the trick.  If memory serves me correct, clockwise increases temperature and a quarter turn is a significant change.  You may want to check there first.

Only outside faucet is a sprayer hose in the utility bay. It has cold and hot valves which are both off.
Not sure where the rear access panel is located. There is what appears to be a removable panel on the front half of the top of the unit.

Jim-

You can always call AquaHot Systems at (800) 685-4298 and ask for assistance.  If you don't have a manual, while on the phone ask them to send you one.  Loren at Beaver Coach Sales there in Bend may be able to help as well, (800) 843-2967.

-Joel

Jim, The rear panel is removed from underneath the coach. If you have a small mirror and flashlight look on the back side of the h.h. unit and there will be a valve with a plastic knob on it. That is the temperature adjusting valve. Turning clockwise increases temp.

If adjusting the temperature does not change the water temp, you can purchase a Temperature Valve Kit Part # PLX-4A8-18R.    Replace the insides like a water faucet.    If I can do it, you can also.  To help you feel more secure, download the manuals ( Maintenance, Parts, Shop etc.) for your model from:

http://www.hydro-hot.com/eSource/ecom/eSource/default/RV_Home.aspx

We also have a trained expert BAC member who will probably step in here soon to advise you.

Larry

Thanks to all. I gather from the responses that the system should be providing hot rather than warm water. We are camping in Portland this week so I will attack the problem when we get home. Probably best not to fool with it now. I might end up with cold showers!

Coach always equipped with Hydro Hot. I mistated earlier. Records indicate "complete rebuild of Hydro Hot, April 2009", $1835.

We had cold water when we got ours and it was a mixing valve issue. The coolent the heat exchanger goes through is 180 degrees so cold water is mixed to cool it down.

We'll a**-umm you've checked the aqua-hot fluid is topped off.

To answer your question, it should be VERY hot. Mine runs hot enough to be quite painful.

Marc Rodstein
2003 Monterey

The reservoir is filled to about an inch and a half above the "cold" line when the tank is warm to the touch (electric power on all day, diesel off).

Jim, your Hydro Hot should make consistent hot water until you run out of diesel.  You should be able to shower for a couple of weeks straight!

A couple of years ago, mine stopped making "hot" water and started to produce only "warm".  The Beaver Coach Sales Service Center had trouble figuring it out.  They decided to replace the mixing valve on the back of the unit because they thought it was "stuck".  It didn't get any better.  Then they zeroed in on the "stir pump" and replaced that, which fixed it.  

The new mix valve came with a tag on it that said it should be "exercised" by twisting the knob and resetting to the same spot once a year.  That suggestion does not show up in any of my Hydro Hot books.

The stir pump is located at the lower right front corner.  It looks similar to the pair of circulation pumps on the left.  Its purpose is to "stir" the coolant in the tank when there is a demand for hot water.  As I recall, trouble shooting is simple.  With your fingers, test the temperature of the hose attached to it when the system is not making heat or hot water.  Turn on the hot water at the sink.  The stir pump motor should run and the hoses attached to it should get warmer to the touch.   On mine, the motor ran but the hoses didn't heat up.  The old pump was dismantled and the unusual internal magnetic clutch assembly was in bits!  The motor was running but the pump was not pumping.

My opinion of the Hydro Hot varies.  When it is working, it is one of the best systems in the coach.  When it malfunctions, it is by far the worst system in the coach.  It is very hard to find technicians that truly understand the maze of pumps, sensors, switches, hoses, lights, circuit boards, relays, etc.    One exception is Roger Burke who has developed a business and Yahoo group around the Hydro Hot.  

Roger maintains a full inventory of parts that he sells at a small discount and he will coach you on doing repairs.  My electric element failed.  Replacement should have been simple if Beaver had not neglected to install a coolant drain.  With Roger's help we invented a way to drain the coolant without a drain!  Roger also rebuild components and sell them where appropriate.  He writes.pdf files covering routine repairs and service for download.  For example, the frequently failing float switch has an easy temporary fix with a "jumper" wire that will get you by until you can do the full repair.  The fun part of Roger's approach to the Hydro Hot is that he is the administrator for his Hydronic RV Heating Yahoo group.  If you join, you will get frequent emails about real issues being fixed with advice from him and others.  Over time you will begin to understand how the darn thing works!