I may have voided my AquaHot warranty

[gumpy]

Winterized my bus in January when we got home from Christmas. As I have always done, I blew out the water lines, pumped RV antifreeze through the lines, and blew out the excess antifreeze. Same procedure I've always used.

Was supposed to take the bus to WY this week. When I hooked up the water to flush the lines and fill the tanks, water started pouring out the bottom of the bus under the AquaHot. I knew exactly what that meant!

I've spent two days now getting it out of the bus, and tearing it down to fix the problem. Probably another two days or more to get it back together and back in. Had to cut the exhaust off. Will be reworking that, as well as some of the plumbing, diesel lines, electrical and water lines on the unit to make it easier to remove the next time.

What a pain in the rear!

The only break in the domestic hot water coil was at the top of the coil, not the bottom. I know why that is. Anyone else want to speculate why. Remember I blew out the excess antifreeze (or so I thought), so there shouldn't have been much liquid in the tube.

[gumpy]

More photos.

[Geoff]

I think you are supposed to blow out each faucet individually which would include the Aqua Hot line.  Somehow you had trapped water in the Aqua Hot line.  So you tell us why....

--Geoff

P.S.  Sorry for you bad luck, that is a big job!

[gumpy]

I think you are supposed to blow out each faucet individually which would include the Aqua Hot line.  Somehow you had trapped water in the Aqua Hot line.  So you tell us why....

Yep. Blew out each faucet with compressed air, both hot and cold. Then pumped 1 1/2 gallons of antifreeze in until it comes out each faucet, hot first, then cold. Then blew out each faucet again with compressed air. Yes, evidently, I somehow had water, or diluted antifreeze, left in the lines.  That part I don't understand. However, when I blow the antifreeze out, I typically try to collect as much as I can and reuse it next fall along with a bottle of fresh antifreeze. I suspect that I may have used some from the fall winterizing, and it maybe was too diluted to adequately protect the lines. Hard lesson to learn for want of a $2 bottle of fresh antifreeze.

As far as the break being at the top of the coil, as opposed to the bottom where the water would normally collect? Well, that's the mystery I was alluding to.

[Geoff]

I'm still trying to wrap my mind around on why we get air locks at all so having the water trapped at the top of your coils falls under the same mystery!

--Geoff

[RichardEntrekin]

Bummer.

Here is what you can do to keep this from happening again. Install three way valves at the entrance and exit to the hot water coil. Use the three ways to isolate the coil from the rest of system and just pump the pink stuff through the AH coils.

Contact me if you like, I can make you a deal you won't refuse on the three way valves. This was a future project that I bought the supplies for, and before I did the modification, moved to Florida.

[Scott & Heather]

Or never winterize! Live Fulltime! Woot!


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[gumpy]

I'm still trying to wrap my mind around on why we get air locks at all so having the water trapped at the top of your coils falls under the same mystery!

--Geoff

Since you're the only one who bit, I'll enlighten you some. The break at the top of the coil is not a freeze break, per se. It's a pressure break caused by freezing water in the bottoms of two adjacent coils. As the liquid freezes it expands in the pipe. Air trapped between two separate freezing pools of water is compressed. Ultimately, the pressure exceeds the pipe's pressure capability and it ruptures.

I'm just glad this was the only break. Fixing it was not too difficult. Getting the unit out of the bus and torn down, not so much! Getting it back together, not so much, also. After 3 full days, I'm about ready to put it back in the bus. I have taken the opportunity to upgrade some things. The webasto has a nasty habit of leaking diesel from an o-ring on the fuel pump. This fuel ends up in the aquahot pan or runs down the exhaust. When it gets in the pan, it would run to the bay.  So, today I welded a couple pieces of exhaust pipe to the bottom of the aquahot pan that will go through the floor. Now, any liquids in the pan will drain outside, not in the bay.  As for the diesel that gets into the exhaust, I'm going to drill a small drain hole in the elbow directly below the outlet and let it drain out. BTW, Webasto won't sell you that 50 cent o-ring, but they sure will sell you a new fuel pump for $400!

[thomasinnv]

So you're saying that the air trapped at the top of the coil compressed enough between two blocks of ice in the lower portion of the coil? Enough that it split the coil? Um I gotta say I don't think so. More likely that there was a highly diluted section of antifreeze or water in that portion of the coil that froze and cracked the tube.

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[thomasinnv]

Craig those little o-rings are notorious for leaking but be sure and check the banjo fittings make sure they are tight and the brass washers are in place. Thats another place they can leak from.

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[Geoff]

What does that "O" ring look like, and why can't you use a new style "O" ring that is impervious to diesel?  My Webasto was leaking out the exhaust after I cleaned it and put a new nozzle on it, and it was leaking from three places that all just needed tightening. Now that it is fixed I probably won't need it until next winter!

--Geoff

[B_K]

Craig how long of a warranty does an AquaHot come with, 20 yrs?

Also I think the reason it broke on top is because the coil around the burner is subjected to some of the heat from the burner (as we all know heat rises) and since the top receives more of that heat it caused the old copper to be more brittle.

Shoot if I were you I'd send pics to the company and maybe they will give you an authorized repair franchise.
  BK 

[Geoff]

I don't know about Aquahot, but the Webasto warranty when I bought mine over 15 years ago was two years from the date of manufacture.  So that's how I got a good deal on mine-- it was three years old, so no warranty!  Luckily, nothing went wrong with it and I have learned how to fix it in the last 15 years.  I have around 500 hours on it.

--Geoff

[gumpy]

So you're saying that the air trapped at the top of the coil compressed enough between two blocks of ice in the lower portion of the coil? Enough that it split the coil? Um I gotta say I don't think so. More likely that there was a highly diluted section of antifreeze or water in that portion of the coil that froze and cracked the tube.

The break was at the top of the coil. There's no way those coils were full all the way around. I blew them out after running antifreeze through the system. From what I understand, most breaks in copper lines due to freezing are actually caused by compressed air in the lines between two plugs of freezing water. Water will move within the line as it expands and the air gets compressed.

[gumpy]

Craig those little o-rings are notorious for leaking but be sure and check the banjo fittings make sure they are tight and the brass washers are in place. Thats another place they can leak from.

Yeah, I have to replace those when I get home. This thing has been leaking all week. Fuel hose split on me at the filter. Have to replace those. The banjos have been leaking. Tightened them and seem to have it stopped now. Put a new nozzle on even though that one was replaced last fall. I did get an O ring for the pump and put it in. It was actually from Webasto, but for a different (probably newer) unit, but it seems to be working for now. I think I'm going to try lapping the inside of that cover just to make sure it's not warped a bit.

It's been a stinking mess this week, though, but at least it's working and keeping me warm.