[Pat Parsons]

Hi All;
We have a 95 Newell coach 392, we are novices as fair as working on our unit...my poor husband, has a wife who is having a fit due to lack of hot water..if you get wet really fast in the shower and shut off the water, lather and shut it off, then turn it back on to rinse you can barely keep from freezing before you are done, that is without washing your hair!!!

This is on electric, with diesel it is immediately hot but does not last much longer...Washing a sink of dishes is not gonna happen no matter how conservative you are!!

I know this can not be right is it?? What are we doing wrong, is there something we have set wrong, not doing right?? We are camp hosting for 6 months and I know this will make me nuts if I have to take cold showers for 6 months!! Any help appreciated, as I said we are total novices to repairs etc, details please!!
best
Pat in the chilly Midwest!!

[folivier]

Someone recently had a similar problem and I think he found out the coolant level in the Aquahot unit (not the overflow tank) was low.
Try turning off the aquahot, let it cool off, then pull the cap (looks just like a radiator cap) and make sure the coolant level is full inside the aquahot. If not then fill it and you will probably need to change the 13# radiator cap, common part, and also change the hose to the overflow tank making sure you have a hose clamp on both ends.

[Trainer]

Pat,

On edit, I see Forest posted while I was writing my reply so I second checking the coolant level. Here is my reply.

There was a recent thread on hot water cooling off that turned out to be low coolant level in the heater tank.

You can check the tank level by cooling off the heater (run the hot water for a while to get the heat out of the tank) and then gently removing the radiator cap.

If low, refill to the neck with 50% coolant and 50% distilled water.

Then check the tube from the radiator cap neck to the overflow tank. If brittle and split, cut off an inch or so and re-clamp to the barb on the tank. You must use a clamp to insure an air tight seal.

If your tank is full, the next suspect is the mixing valve located just below the black burner case. To test with the heater up to temp (electric and diesel switches ON), turn on the hot water and feel the pipe coming from the tank to the mixing valve and feel the pipe going from the mixing valve to the coach. Pipe from tank should get real hot and stay real hot. Pipe from valve to coach should get real warm (120 degrees F) and stay that way.

With you experiencing hot water cooling off and a full tank of coolant, I would be looking for the pipe from the tank getting real hot and staying that real hot but the pipe from the mixing valve getting real warm and cooling off. This is a symptom of a failed mixing valve.

The fix is to replace the guts of the mixing valve which is not hard to do. Order the parts from Roger Berke at

http://www.parts.rvhydronicheaterrepair....egoryId=-1

The only fly in the ointment here is if you are using water from the water hose in cold conditions, the heater may not be able to raise the water temp enough for you to have hot water. The spec is 55 degree rise in temp at a flow rate of 1.5 gallons per minute. So if your incoming water is 40 degrees, the best output water would be only 95 degrees and would feel cool.

The fix here is to turn the hose off and use water from the coaches fresh water tank.

Hope this helps you.

[encantotom]

great advice.

the mixing valve is a standard watts valve. i bought my last two of them for about 30-35 bucks and then took the guts out to put in. one in my 02 and a complete valve in my 90.

tom

[encantotom]

if it ends up needing to replace the guts on the mixing valve, do a search on ebay for watts tempering valve and the 70 series either 1/2 or 3/4" have the same guts.

there are some there for about 40 bucks shipped.

tom

[rheavn]

Pat,
You have received outstanding advice. Look at all four scenarios carefully: low coolant, bad hose from the AquaHot tank to the surge tank, bad mixing valve and cold water issue coming into coach. Below I posted a picture of the piping that Rudy told you to check with the mixing valve. The mixing valve has the black knob where the hot water goes in and warm water goes out. This piping is located below the black diesel burner.

Also these units need annual service. Has the unit had its annual service and the mixing valve exercised? Exercising the valve is simply moving the valve knob to the left & right and then recentering--usually only can be done with the diesel burner removed. Instructions on servicing your unit are posted in the "Documentation" section of this web site under "heating systems". You can evaluate whether you have the tools & ability to perform the service. If you have any questions, email me & I'll send you my phone number.

[whatsnewell]

This site is almost better than live tech support....I don't have an aquahot, but I know, based on the preceding posts, how to service one now!

[bestgenman]

Another check to see if cap is tight.

Watch the overflow tank level when hot and compare to when cold, there should be a difference in level (fuller when hot). If you are not seeing this level change, you have a leak in the overflow plumbing.

Another thing I have found: Running on the Headhunter pump and filling the tank when needed keeps the pump active and the water in the tank fresh. Caution on letting the tank level get low enough to introduce air into the pump can cause a headache getting the air out!

Steve Bare's drawing is very helpful in locating the correct pipes.

Gordon Jones

[rheavn]

Good point Gordon about the radiator cap.

Pat,
Make that the 5th important thing to check. Check that cap real good & replace if in doubt. 13# cap from Wal*Mart or an auto parts will do.

[Pat Parsons]

Thank you so much, you guys are amazing!!! I am passing this to the husband who will work on this in the day light!! I cannot thank you all enough!! Special thanks to Tom!!

Will let you all know what we find and how we do!!
best
Pat