How to service mixing valve on G16EXT - RTO Atwood Water Heater - 6 Gal LP

Check two things, 1- check that the hot water heater bypass valve is completely closed so that it is not bypassing at all and mixing cold water . 2- check your outside shower valves, make sure both of those are turned off...if they are turned on but the valve on the head is turned off...this will also allow cold water to mix in the hot water line. If those check out ok...then the mixing valve is likely clogged, you could take it off and try soaking it in boiling white vinegar, or try to adjust it, there is an adjustment screw under the black cap, I think its an allen screw...but they fill the center with glue so you can't adjust it...you have to dig that glue out so you can get the allen wrench in...may even be a torx screw...either way it can be adjusted, you just have to dig the glue out first.

Bad single-handle faucet cartridge.
Bad check valve.
Bad mixing valve.
Test for crossover.
http://waterheatertimer.org/Crossover.html

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

ssounds more like mineral deposits or blockage of some kind is keeping it from running effiacntly by telling the sensor its hotter than it is. Good luck!

Valve is not identified.
Cold water shut-off valve, TP valve, check valve, mixing valve, drain valve are the usual suspects associated with electric water heater.
Gas water heater has additional valves: gas shut off valve and gas control valve thermostat.
Check valve, TP valve and mixing valve probably need replacement.
If drain valve is leaking, put garden hose cap over end.
Shut off valve probably has a bit of blockage, or is not completely open. Try closing and then opening shut-off valve all the way, and if problem persists, replace or clean out valve.

What kind of noise? Are you sure the noise is from a valve or is it inside the tank caused by sediment build-up inside of tank?

http://waterheatertimer.org/Clean-sediment-out-of-water-heater.html
http://waterheatertimer.org/Low-hot-water-pressure.html
http://waterheatertimer.org/How-to-replace-TP-valve.html
http://waterheatertimer.org/images/Water-heater-with-mixing-valve-300.jpg

If some taps have really hot and others luke warm, then you might have defective mixing valve, check valve, or crossover on single handled faucet.
http://waterheatertimer.org/Crossover.html

Crossover can also cause stacking event. Stacking could be part of puzzle.
http://waterheatertimer.org/Stacking.html

Once crossover or check valve or mixing valve problem is solved, if you have really hot water to some taps, then turn down thermostat to avoid scalding.
http://waterheatertimer.org/How-to-adjust-temperature-on-water-heater.html

Add a comment for more help.

Amdrol makes indirect-fired water heater that gets heat from a boiler
http://www.amtrol.com/boilermate.htm

1) Pdf manual on amdrol website show a mixing valve that mixes cold water with the hot water so water temperature going to faucet stays the same:
http://www.amtrol.com/pdf/MC10169%20BMconstantempflyer.pdf
You set the temperature of the mixing valve.
You can also set up 2 sets of pipes ... one is connected to mixing valve that goes to sinks and tubs. The other pipe bypasses mixing valve sends hotter water to washing machine.



2) The manual for Amdrol:
http://www.amtrol.com/pdf/9040-586%2001_09%20BoilerMate%20Indirect%20IO.pdf
The new models has a temperature sensor that plugs into digital readout.
This is a thermistor sensor wire that can be ordered as repair part

3) Amdrol has e-mail address:
[email protected]

4) You can post your question on a water heater forum
http://www.thetankatwaterheaterrescue.com/forums/forum3/

If you aren't getting any error codes, then the heater is probably doing its job. Your problem is probably somewhere in your plumbing system. The most common reason you get this sort of problem is due to cold water mixing in the hot water system. There are a number of causes for a "cross connection" :

-Faulty check valve
-Missing check valve on reciculation return line
-Faulty shower cartridge
-Thermostatic mixing valve set too low
-Faulty thermostatic mixing valve
-Faulty anti-scald valve

The easiest way to confirm a cross connection is to: 1) shutoff the cold water entering the tankless heater 2) open hot water valves around the house. If you still have water flowing at your hot water fixtures, then you have a cross connection.

Something is blocked. Turn off water to heater disconnect outlet and attach a waterheater flex connector to tank outlet bend other end into bucket. turn on water briefly - water should blast into bucket.
If not:>>>>>>>>>> disconnect water heater inlet -you may find part of the flex washer stuck into the inlet nipple. Or dip tube may have disintegrated and be plugging outlet nipple, if you have the energy saving nipples the ball can jam debris in the nipple.
If water does blast into bucket >>>>>>>>>>>> Then the problem is farther down the line, maybe bad mixing valve. disconnect mixing valve outlet and use a garden hose to backflush through mixing valve with bucket under hot pipe disconnected from water heater. If flow through valve is restricted, replace valve.

if you are using a mixing valve it is pre set so as to not burn your self but if you wish to set it on the dial depending on which one you have, some are flat tip screw driver some have plastic cap on it turn on the water and set to your desired temp by turning clock wise or counter clock wise

there should be a flat head screw on the mixing valve turn the water on and turn it to the desired temp,, it is letting to much cold water in , if this does not work replace the mising valve