AquaHot Controller Location???

[Rick Vyncke]

Where is the AquaHot controller located on a 2004 Beaver Marquis.  I’m not asking about the switches that are used to turn it on and off.  Rather, there is supposed to be a control panel that has status lights for troubleshooting.   

Trying to diagnose an issue. When I turn diesel burner on the light goes off within about 30 seconds.  Just had it serviced and the tech said everything is working well…..  I’ve been plugged into shore power for 24 hours and so the tank has got water because of the electric heating element but am getting ready to start day and want the diesel burner on so that we don’t run out of hot water…. Is it normal for the diesel burner light to go off when the water is already hot???   Or does this indicate a problem with the system?

Thanks

[David T. Richelderfer]

We have a 2004 Beaver Marquis.  It has the Aquahot model AHE-100-02S.  The 02S model does not have a "control panel," per se, with status lights.  Its controlling hardware is located on the upper inside of the Aquahot facing the square stainless steel box access door.  There are no other buttons for the unit, other than its ON-OFF switch located in the living quarters.  The ON-OFF switch's light should stay on when the Aquahot is alive and well.  If the switch's light goes out, then the controlling hardware has detected a problem and will not allow starting the diesel burner, although the electric element should remain functioning... unless it's bad too.  The electric element in our Aquahot provides enough hot water for two medium length showers.

How long since its last service?  There are several items that can be your problem - in need of an annual service, flame sensor blocked, dirty filter, fouled diesel spray nozzle, bad igniter module, coolant too low, etc.  An annual service will cost $200 to $300, not counting modules, if bad.

[Fred Brooks]

   Rick,
 If your aqua hot is up to temperature, the diesel will not come on because the internal thermostat is satisfied. To check if the diesel part is operational, go to the circuit breaker box and turn off the breaker identified as "water heater". Then turn on the diesel switch and open any hot water faucet and wait about 7 or 8 minutes. Go outside and you should hear the aqua hot diesel burner come on. In the event that does not happen, there is a fault in the system. Fred

[Rick Vyncke]

Thank you Dave and Fred!!!!

I had it serviced 2 months ago and took it to a second facility to check it last week before we left on vacation.   The service include annual replacement of burner’s nozzle and a new sensor eye.  The most recent check-up they said everything was functioning normal.

Now the light illuminates for 30 seconds or so and then goes out.  Ugh

Fred - I understand the burner won’t ignite if not calling for hot water.  However, should the green “diesel burner” light stay illuminated when turned on?   I will go try your suggestions now.   Thank you!!!!!

[David T. Richelderfer]

As I stated earlier, if the Aquahot switch is ON, then the switch light should stay on.  The switch light does not tell you the diesel burner is running; it tells you the switch is ON and the Aquahot is alive and well.  With the switch ON, when the burner thermostat calls for heat, the burner will ignite.  Also, turning the ON-OFF switch OFF and back on performs a reset.

After trying to remember my experiences with our Aquahot, I would 1) check the coolant level.  It's very easy to check and to add coolant.  And 2) if memory serves, we experienced the exact symptoms (switch light goes out after 30 seconds) when low on coolant and when the glass cover protecting the flame sensor became sooted over.  Can you hear the Aqauhot start whining when the switch is turned on?  Then after a few seconds, can you hear the diesel burner light up?  These answers provide clues as to where to look first.

BTW, what model of Aquahot does your Marquis have?  Importantly, my comments are based upon my experience with the model I have - the AHE-100-02S.

[Joel Ashley]

Assuming David’s surmisation is correct and you have the same model as he does, you won’t find the “control panel” found in more recent ones, like our ‘06 Monterey.  It would certainly help if you had it since indicator lights on it’s front indicate where an issue is, like low battery power or fluid issues;  it’s saved me a time or two, quickly zeroing in on some system failure. 

As David reiterated, if your on/off diesel switch is “On”, it’s lamp should stay on unless there’s a problem.  Check the troubleshooting areas of the manual, beginning on pg. 45:

http://www.aquahot.com/files/service_manual/AHE-100-02S%20Service%20Manual%20Rev.%20B%209-27-2011.pdf

Joel

[Rick Vyncke]

Worked through some of the troubleshooting but cannot find the float switch to test it.  Am thinking it is a bad float switch or possible the coil.

The pump starts as soon as switch is turned on but it never fires.  The light goes out after 20-30 seconds but the pump continues to run for 2+ minutes before it turns off.  I was not expecting that. 

Looks like I’m without the AquaHot until I return from vacation and then have it looked at again.

If anybody knows the location of the float switch… let me know. 

Thanks

[David T. Richelderfer]

The Aquahot will run for 2 to 3 minutes to complete its purge cycle.  It performs a purge cycle every time it has been running and turns off.

[Joel Ashley]

Ours may be a different model but yours probably is similarly designed re. the switch.  It is of course a float switch and thus is inserted into the side of the main fluid tank, somewhat below its top.  You should locate its two yellow wires that emanate from an approx. 1” diameter hole through the foil-faced insulation.  In the photo below it’s visible to the right of the orange 120v. “house” cable and above the bundled 12v red connectors.

I had to replace mine last year, and it was an adventure.  The plastic part of the switch had snapped.  A newer version less susceptible to that was designed and was what I ordered, after some price shopping I think from John Corrillo’s site.  https://heatmyrv.com/product/ele-800-002-switch-float-brass-12vdc/

Follow troubleshooting instructions in the manual, but if you find the switch failed, I can resurrect memories and notes to try and help further.  Getting the old one out was no picnic as a special socket is necessary to protect the wires.  And there was confusion over the correct socket size.  You’ll also need to drain some fluid to get the level below the level of the float if you find it necessary to remove the switch.  I managed to attach a hose to the drain valve and route it through a nearby hole in the bay floor and into a plastic pan for a clean job.

Joel

[Steve Huber]

Check the electrical diagrams for your unit as you should be able to jumper the 2 wires from the  float switch if you just have a faulty switch. That should get you heat till you get home.
Steve

[Joel Ashley]

Thanks to Steve for reminding me of that.  It’s very easy to bypass (jumper) the switch on the control board to see if it’s the problem.  But we are reminded that Rick may not have the same control board as such.  The wires, though, still have accessible connectors just outside the tank that can be jumped.

Joel

[Rick Vyncke]

Thank you all for the valuable input....  Problem solved and wanted to share a few thoughts for others who are having AquaHot challenges...

1) Ensure you have the correct service manual.  There are some fairly significant differences even when they look similar.   I was searching for a float switch per the diagnostics and could not find one.  I discovered that I had the incorrect model’s service manual.  After finding the correct manual I realized that’s mine does not have a float switch.

2) After testing as many of the electronic components and verifying that they were working, I took it to the local repair center.  They discovered the fuel pressure was too high.  Ultimately, this caused excessive fuel in the combustion chamber and basically flooded the burner.  They adjusted the pressure down by about 12 lbs and problem solved.

3) The folks at AquaHot provide outstanding customer service. They answered all my questions and sent parts to me overnight while we were camping out of town.

4) The value and knowledge of members on this forum is incredible.  Thank you again!

[Joel Ashley]

No float switch?  That’s a new one.  How does it monitor for a low fluid condition, other than a perhaps less reliable overflow tank?

[Rick Vyncke]

Not sure Joel.... When I could find no reference to it in the service manual I called AquaHot and told them I couldn’t find it.  After asking what model we had.... he said “that does not have a float switch”.