Hydro-Hot Emergency Cutoff Issue

[Bill Dean]

Specs - 2001 Beaver Patriot Tic 37 w Hydro-Hot model HHE500_03M.
We bought our RV in January from Beaver Coach Sales. In the inspection, the HH tested fine, had been serviced & the stir pumps had been replaced.
Our first "shake down" trip up to the foothills, found the HH wouldn't function. Upon inspection, found that the plastic  reserve tank had no antifreeze but the main tank was full (fluid spilling out when I opened the top cap).  Went & bought some antifreeze but the red cutoff light would not turn off. On the return trip, the vibration from the road kicked the light off. Found that the leak was the hose connection at the bottom of the tank - fixed it & no more leaking.
Now, we just went up to Henderson Lineup for new Koni shocks & then to Newport (high one day of 88 degrees) & the HH performed great until this morning. Again the red cutoff light was on but the reserve tank was exactly where I had previously filled it to - midway between the "cold" & the "hot" marks.
I just pulled into 7 Feathers RV Resort & the light is off & the HH is working again (from the road vibration?).
I just don't understand what's going on or what to do to fix this issue. The manual states that it is an automatic "reset" & I can attest to the fact that the recessed reset (via toothpick) doesn't affect this issue.

[Joel Ashley]

From time to time I've run into times the unit stops working too, Bill.  No clue exactly why.  But as long as I can reset it at the monitor panel in the HH bay or just shut the unit off and on again at the switch inside, it has always come back to life for us.

Some units use other fluids, but standard practice dictates Boiler Fluid in them, so I hope that's what you bought and added to top off the tank.

If it keeps it up though, perhaps it should be checked by a tech, or head over the hill to BCS one more time.  Our own in-house AquaHot specialist, Orman Claxton, may have some ideas for you.  

Joel

[Bill Dean]

Thanks Joel,  I tried everything - both the switch in the coach as well as the HH bay reset to no avail. And, no amount of waiting does anything but frustrate me. The last thing I want to do is have to unhook everything and drive down rough roads until it decides to come back on.
BCS or Orman may be my only solutions as there's no certified techs in my part of the wood north of Napa County.

[Orman Claxton]

Hello Bill
 Maybe I Can help.  #1 your manufacture year tells me you will use the standard antifreeze.
The manual reset the book speaks of is coolant float switch, located at the top left (after cover is removed) Two wires coming out, plugging into two other wires.
First Step, Manually check coolant level, clamp off the small hose from the tank, DO NOT depend on the coolant tank level, verify coolant level.
Second, IF the RED light is on, unplug the two wires from the switch, plug an automotive fuse into the other 2 wires, Did the Red light go out? If so, then you have a faulty float switch.
This can be operated temporarily, as long as you are positive the coolant level is full,  

DO NOT LEAVE THE FLOAT SWITCH BY-PASSED, this is a safety for both Electric and Diesel

[Bill Dean]

Thanks Orman!  When I get home I'll follow through with your instructions. I did buy and top up with standard antifreeze as that is what was referred to in the manual that I have.
As to checking the actual coolant level, I will do what you have instructed. When the first incident happened, as previously mentioned, I did open up the coolant tank and it was at the top and dripping out of the opening.
I am suspicious of the float switch and will certainly follow through.
Again, thank you!!!

[Joel Ashley]

Orman-

What year did Vehicle Systems go to Boiler Fluid, and how much does it really matter?

-Joel

[Orman Claxton]

Joel
Aqua-Hot switched to Propylene Glycol in 2004/2005
The system design led to using Propylene Glycol  because of a possibility of Ethylene Glycol leaking into the domestic water system.
They Cannot be mixed, However Propylene Glycol can be  used  in earlier systems as long as the system is thoroughly flushed before changing.
There has been instances of owners mixing the Camco antifreeze with the Camco Coolant, (Very confusing as they are the same color) However, these cannot be mixed. If mixed there will be serious problems of contamination,  along with Heat exchange properties seriously changed.

[Joel Ashley]

Thanks for the info Orman.

Fortunately we only need to carry onboard extra boiler fluid coolant, because as you point out the winterizing antifreeze looks just like it.  Both in the same plastic gallon jugs, I can see where lost labels could prove disastrous to a careless or inexperienced owner.

Joel

[Orman Claxton]

Yeah Joel
Yours would be a lot easier to take care of, (as mine)
But, It is a problem, sadly too many people aren't aware of the problem

[Bill Dean]

Well, the fun & education continues. So, I ordered the float switch from H-H & it arrived promptly. Yesterday, I went over to the covered storage (over an hour away) & drain out the antifreeze from the expansion tank & then the main tank - all goes very well with hardly a drop spilled (I used a manual suction pump portable tank with a three foot 3/8" tube).
Looking at the side of the tank, I see two sensors screwed into the tank - one top right & one 1/3rd down somewhat centered. Well, that certainly had to be the culprit - NOT!  I don't know what I pulled out (photo attached) but I had to splice it back together & get it seated again - yikes!
Then I frantically search & found it hiding behind an electrical junction box firmly attached to the top of a second electrical junction box!  I have absolutely no idea how to get to the float switch other than taking all of this mess apart.
AND, I do mean mess because the lower junction box also has a potted "whatever" going into the tank with two badly corroded wires detached (perhaps the Electrical Heating element?). BTW, I never was able to get the electrical heating to work - so, another problem reveled but certainly not solved.
So, I filled both tanks, put together a jumper (two male connectors with a two inch wire), disconnected the float switch (connectors were about six inched from the switch) and then turned on the diesel heat & it immediately fired up. I let it run for a while, checked for leaks & then buttoned it back up.
Now, how on earth did Beaver decide to permanently attach two junction boxes right in front of the float switch and how on earth am I to fix this?  
Any suggestions or do I have to drive up to Bend?

[Bill Dean]

Here's the detached & badly corroded wires in the lower junction box.

[Orman Claxton]

Hi Bill
The part you removed is the thermostat,
The float sw. is behind the Junction box
The badly corroded wire looks like the Heating element, there is a VDC switch that controls the relay which seems to be in the lower attachment.
if you wish to do your own repair, go on the A/H website, down load your manual, it will be much easier to understand the locations of the different parts.
All you need is your Model #

[Orman Claxton]

So, I filled both tanks, put together a jumper (two male connectors with a two inch wire), disconnected the float switch (connectors were about six inched from the switch) and then turned on the diesel heat & it immediately fired up. I let it run for a while, checked for leaks & then buttoned it back up.
Looks like I Missed that part of the post

If it fired up, sounds like the float SW. is working unless you have it bypassed
I seem a bit confused Maybe
 

[Bill Dean]

Thanks Orman. The main issue I have is the mounting of the junction box right in front of the float switch. I'm not sure how to remove it. Have you dealt with this problem before?
BTW, thank you for your input & support. It's great knowing that the BAC has such a knowledge base as you represent.

[Bill Dean]

Orman, yes I did bypass it with a jumper I made.