Aqua-hot system leaking

[Mike Sulley]

Wishing you all a very Happy New Year from Alaska.

I need the combined wisdom of the group.  I did a google search of AH leaks but didn't find a solution to my problem.

I am a relative 'newbie" to RV'ing.  I bought a 2001 Beaver Marquis Amethys a few years ago with no previous RV experience.  We are just seasonal campers.  And our season is short.  So for the last couple year, every time we started the coach the Aqua-hot fired right up.  No problems, my moto is "If it works, don't fix it".   I just kept the overflow jug filled and all was well.  Well the last trip of the season it did not fire up.  (We still had hot water.)  Thankfully, we were not far from home and our son brought a couple electric heaters so we could finish our weekend trip.

Our Aqua-hot is an AHE-100-01  SR # 047, so no modern "bells and whistles".  Once home I found the AH reservoir empty.  So I added a couple gallons of fluid and used the three zone pumps to attempt to fill the system.  I pressure tested the system and kept getting different results.  Some time it would hold and sometimes not.  I then proceeded to do an annual maintenance, Pinched the fuel lines, replaced Racor filter ( the one with the clear sediment bowl/ drain), and opened up the burner assembly.  It was all covered with soot.  Cleaned up the tube, vac-ed out the jacket, replaced the photo disc and nozzle.  Noticed the diesel lines to the burner pump were cracked so i replaced them too.

 There was evidence of boiler fluid on the AH cover, so I pressure tested the rad cap.  It only held 3-4 psi so I replaced it with a new 13 psi cap.  Suspected it might have over temped so I Ohm tested the 2 high temp shut-offs and other 2 temp sensors as well.  All 4 had continuity.

I was ready to test the system.  Added a couple gallons more to the tank and put 10 psi. on the AH tank just to watch.  Started the coach and turned on the thermostat.  Checked the burned for the motor whine.  No temp increase.  No indication of burner firing.  Started looking around and noticed about a 1 quart leak of boiler fluid the cement under the driver's seat.  Crawled under the coach, just barely and saw boiler fluid leaking from under the floor down around the steering shaft and on to the steering box.

This surprised me as the front zone heater is on the floor behind the passenger seat.  I am guessing there is a leak in the Pex? tuning.  No idea why it's routed under the drivers side of the coach. I have not opened up the front zone radiator which behind the passenger seat.  I guess that's my next move.  Has anyone replaced a plastic heater line?  Are there any floor plan drawings of the heater zones?  Is it possible to snake a new line in to replace it without cutting up the floor?

One other surprise, there is no diesel in the Racor diesel filter so the burner couldn't fire up.  Those lines are pretty hard so I used metal threaded clamps, but they don't appear visually to be collapsed.

I apologize for being long winded.  It's a handicap of being an engineer.

Would appreciate any and all thoughts,

Respectfully,
Mike Sulley
Nikiski, Alaska

[Carl Boger]

Mike,

I don't have a Aqua-hot but have a Hurricane instead.  If you can find a place in the line before the leak you can run a new pex line to the front heating zone bypassing the old line and running it the easiest way possible.  The old line can be left in place and abandoned.   The line itself may be a plastic that was used before pex, but pex fittings can be used with it.
Good luck getting back on the road.

[Steve Huber]

Mike,
I'd check the connections at the front heat exchanger. The leak may be there and the fluid is then running down the pex tubing and dropping off at the low point. Pex is pretty tough and the fluid is an antifreeze, not water, so unless the tube got badly worn due to chafing, I'd classify a bad section of tubing as a fairly low priority.
Steve

[Mike Sulley]

Gentlemen thank you for your response and your ideas.

While climbing around on my hands and knees checking out the radiator behind the passenger seat, I noticed another radiator on the floor under the center dash/ entertainment console.  I could then remove the drawer above the radiator for a better look.  Still not enough room to do any work on the ends of the plastic lines.   There were no visible signs of a leak stain.  This makes more sense of the leak coming down around the steering shaft.  So the leak must be under the floor between the radiator and the Aqua-hot.

I can only see a few inches of the line before they disappear under the floor.  As I see it, I will need to remove the console in order to perform any work on this end of the lines.  With access to the lines I can disconnect the lines from the radiator and pressure test each line to identify which is leaking.  Hopefully the lines are not clamped in place and the damaged line can be pull out and replaced with a PEX line.

Does anyone have any ideas on how to proceed, or how to remove the console?

Thanks,
Mike Sulley

[Carl Boger]

I am not sure if your front radiator is set up like mine, but after removing the top of the console and the drawer I was able to radiator and get a little access to the area.  I really doubt that you will be able to easily remove either line so I would add air pressure and try to locate the leak.  Then cut it before the leak and run pex from it to the radiator.

[Eric Maclean Co-Admin]

Mike
In my coach the top or shelf on that center console was glued to the top of the console using silicone there was also a bracket and screw from under the dash into that top panel take out that screw and pull up on the top and the silicone will come loose ( it takes a pretty good pull) this will give you good access to that heater rad .when your done you just silicone it back in place.

Eric

[Mike Sulley]

Gentlemen,  A little follow up so far.  Several of my pressure tests have been misleading.  Sometimes they appear to hold and other times not.  I guess it depends on where the fluid is moving arounin the system.  I have not been topping off the reservoir with boiler fluid because it is getting expensive.

Steve made the right call.  It was not the line that was leaking, but a slow drip at the hose fittings at the heat exchanger.  Found a couple loose hose clamps on the rubber right angle boots connecting the plastic hose to the exchanger.  As a note,  I did find a good selection of silicon hose 90's that could be trimmed to fit if required to replace the boots at our local industrial hose supplier.  I did use coast guard approved marine hoses.

So I have tightened the offending clamps, no easy thing,  and am now in the process of pressure testing to confirm pressure integrity.

I have replaced the Racor filter and replaced as many associated burner hoses as I can.  Unfortunately, I can't get access to the top of the diesel tank to replace that hose to the Racor filter.  So I have left it.  It's rock hard.  My problem now is that diesel is not gravity feeding into the Racor filter.  I have purchased a primer bulb to give it a try.  If that doesn't work, I will try to apply pressure to the  diesel tank.  Any and all ideas will be appreciated.

Respectfully,
Mike Sulley

[Carl Boger]

Mike,

If you need to replace the fuel line going to the top of the tank you don't have to drop the tank all the way down.  On mine I drove all 6 tires up on ramps lifting the MH 4.5 inches and then put a  motorcycle jack under the tank, loosened the straps took off the fuel fill hoses and lowered the tank.  I then removed the front strap and tilted the tank down to where I could reach the fittings.

The tank doesn't have to move all that far.  Hopefully you won't need to replace the hose, but it is doable.

[Steve Huber]

Mike,
Be sure your fuel tank is at least 1/4+ full. The feed line for the AH and geni is about 1/4 ways up the side of the tank.
Steve

[Mike Sulley]

Hey Carl,  Thank you for the reply.  I do want to replace that hose ( not really.  But should).  So that sounds do-able.  Luckily for me.  My tank is clear full.  But I have the motorcycle jack and tools.   So will probably run the tank dry this summer and do it this fall.  I will have to build the ramps to raise the coach.

To update:  Typical of working on old equipment, it's two steps forward and one step back.  The marine primer bulb worked like a charm.  Placed it in the line below the filter down at the Aqua-hot manifold and was able to pull fluid from the diesel tank into and thru the filter.  Had to put my finger over the end of the primer bulb after I squeezed it, but before I released the squeeze.  Once I had fluid into the bulb, I removed the bulb from the line and replaced it onto the Aqua-hot manifold.  Attempted to catch the diesel in a cup.

I had to re-rig my little 25 psi pressure test manifold (i'm using an air compressor) because I had to use a smaller hose than the hose barb I had (I connected the manifold and "jury rigged it" by splitting the hose) and putting a hose clamp on it.  So today I had the correct size 5/16" hose and hose barb fitting.  As my luck would have it,  while twisting the hose to pull it off I pulled off the little fitting below the radiator cap to the overflow bottle.  So I get to re-attach it and solder it back on.  And not much space to work in.  But was able to pressure test the system and it looked promising.

Thanks for all the help.
Best wishes,
Mike Sulley

[Mike Sulley]

Thanks Steve.  I will keep that in mind.  I AM learning more and more about these coaches every day!

Thanks so much!

Mike