A friend of ours is having a problem with his Aqua-Hot system, it has developed a leak in the hot water side inside the closed box portion of the system.
He has called Aqua-Hot and they have told him that there is 160 feet of 1/2 inch copper tubing around the heating tank inside the box and that it would be over $6,000.00 for an exchange unit.
Has anyone had experience with this system and has anyone had any success removing the system and repairing a leak.
Aqua-Hot does not give very much info and says that the unit can't be fixed, but needs to be replaced. Does anyone have first hand knowledge of what is inside the sealed box and if so, any ideas as to how to repair the leak.
Any help and/or info would be appriciated.
The system is on a 2004 Holiday Rambler Navigator
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edited 08/16/10 07:31am by an administrator/moderator *
Paul & Ellen with Daphne & Digby 2006 HR Ambassador 40 PLQ, 2004 Jeep Liberty. F.M.C.A. F241322
Good Sam
Wow. Talk about a topical question. I had come to the forum to make a post "Today's the Day! " with the subject being the repair and re-assembly of my Aquahot 411/12, when I saw your post and thought you might like me to hijack it instead!
History: My aquahot was frozen up while the coach was on the dealer's lot i bought the coach from - Keystone in PA. Before everybody gets excited, I was aware of the problem when I bought the coach! When I opened up the shiny stainless steel Aquahot box (I was a contortionist in a previous life!) the burner and some other parts were lying in a pile, the AC had been cut off with wire clippers, the runs to the engine cooling and domestic water were looped together, and the heating runs were capped off. Oh, and the system was drained of antifreeze. The best information I have is that the dealer didn't winterize it, or just blew out the taps, and then after freezing up some lines came back and tried to do a super-winterize. Who knows?
Oh, and the unit had been unbolted from the chassis and was loose in the compartment.
We took all the loose pieces out, and then tried to remove what I call the back cover. For those of you who aren't familiar with it, that model of Aquahot is a rectangular box about 20" wide by 20" high and 36" deep, when viewed from the compartment door. The 'front', closest to the compartment door, has the connections for the domestic water and engine coolant at the bottom edge in a row, and the connections to and from the house heating loops at the top left. the burner, circulating pumps, tempering valve, and controls are mounted in the front third of the box. Behind that is a vertical stainless steel panel dividing the main box into two sections, a 'front' and a 'back'. The back is what FeeLine, the OP, called the 'closed box' portion of the system. Once we pulled the whole Aquahot unit out of the coach, we were able to remove the cover on the back section.
Inside the back section is the main Aquahot boiler, which looks like a steel can with another steel can welded inside it, lying so that from the front you see the flat end of the cans. The inner can is the firebox, where the burner fits, and it only goes partway back (so the outer can is not a doughnut). On the outside of the main boiler (the outer can), a coil of 1/2" copper tubing is neatly but loosely wrapped around it. This coil is bedded in a thermally conducting refactory cement to ensure good heat transfer to the domestic hot water. This whole thing is wrapped in a layer of fibreglas or mineral wool insulation.
We then determined that to work on the coil we needed to remove the boiler body from the Aquahot frame. This entailed de-soldering all of the fittings on the attached piping as the holes in the frame and divider sheet were only big enough to pull the pipes and tubes through. Once that was done, we took the boiler body and the coil and examined them, determining that there were two fairly large splits in adjacent coils. We decided that the best way to repair it would be to cut out the split sections, sacrifice one turn on the coil, and just reconnect it and go on. My figures are that with 30 turns, one turn represents a sacrifice of about 3% of capacity, which is a price i can live with rather than winding on a whole new coil. "Flyawes" now, on his opted to wind a whole new coil and is very happy with the results.
After 3 hours work for 2 guys, none of it very hard, we are now ready to solder it up. We found a piece of copper tubing which nearly matches the OD of the coil tube with it's ID, and have it shined up ready to silver solder to the two good prepared ends of the coil. We have also cleaned up the remains of the refractory heat transfer compound Aquahot used to bed the coil in. Flyawes generously gave me the name of the heat transfer compound that somebody from Aquahot told him they use, (he's obvoiusly a lot better at 'social engineering' than I am - you'd have thought I asked for the secret to getting the caramel inside Caramilk!) and I have a gallon of it which arrived Friday from a supplier in New Jersey.
So, this morning the plan is to silver solder it up, then slather the paste onto the body, bed the coil in it, and then fill in the cracks. Once it dries, we'll be ready for reassembly. Wish us luck! I've a feeling good will be a good thing, but today it might be better to be lucky!
Looking for Free Wifi I noticed SSID " HRM_Police_Surveillance_Van_#2" Think it's safe to connect?
fulltime 6 months/year FMCA 368297
98 Beaver Marquis, one slide, CAT425HP, 2 stg Jake, Allison MD4060, Aquahot, 10KwOnan, 3Kw Xantrex, HWH Air Levelling
I just thought that I should mention that the two of us tackling this project are not particularly more skilled than normal. But, we both aren't scared to tackle things. I'm an engineer who at one point had a license to make any changes I wanted in my company's processes, as long as my staff could make the required equipment, and my friend is multi-skilled and extraordinarily self-reliant.
But this is a project that, say, Mike, or anybody who can weld and fabricate a little bit could do. The big challenge is mental!
As for costs, I would think that even if you had to pay people to do this work, you could have repaired mine for about $500. My out of pocket cost will be under $200 because the heat transfer cement cost over $100 landed here (mostly freight and brokerage)The rest is bolts and about $75 for new nozzles, gaskets, and filters.
I would recommend you put a radiator pressure gauge on the antifreeze reservoir at the engine and pump it up to about 13-15lbs. Then you will go to the unit and look for leaks. Also the pressure will drop if their is a leak.
We took ours in to a service center for a leak and they completely removed the unit said we had a leak inside the unit removed and repaired??
4 weeks later we took it home fired up the unit still had a leak??
They didn't do a pressure test before removing. I got a tester from a friend of mine and did it myself. Sure enough one of the hoses coming from the engine into the unit had a pin hole in it. It was running down the hose into the unit and it made it look like the leak was inside.
A $2.00 part from NAPA and a couple clamps it's fixed.
Roger they talked about was a huge help for me trying to find the problem. Good luck and hope this helps.
IF he truly has a leak INSIDE the boiler at the hot water coils, the best test is this----Connect to city water and IF the overflow reservoir overflows after 24 hours or less, the inside coils are bad. Yes, Aqua Hot does NOT sell the individual parts for that part of the system. They require to either send in to be rebuilt or you purchase a rebuilt unit. Doug
Good Issue, Doug. FeeLine, what model does he have? Some have the wrapped coil, some have the coil inside the boiler. The model number will tell us which.
Further to my earlier post, the soldering is now done, the goop is on, the boiler is mounted and piped up, most of the wiring is done, the insulation is back on,..... I just need a new radiator cap, a question on the wiring answered, some fuel line, and tomorrow we will test fire!
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