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Topic: Aqua hot Rebuild (Read 4648 times) previous topic - next topic

Aqua hot Rebuild

I had a question about my aqua hot rebuild so I though I would share my experience and steps that I went through to save us $10,000.  (We live in Canada so the exchange is brutal.)

1.  Have a drink, seriously.  This may seem daunting, it is not.  Time consuming yes.  You will need 2 people.  And you will have to be flexible to get it in and out.  Also, you will need a 5 gallon pail of heat transfer mastic from Chemax.

Chemax Mfg-Since 1954-Heat Transfer Cements (Mastics)

You need the 5 gallon Tracit-600A

2.  We are a 2001 U320 so our Aquahot is in the middle upfront between the coach batteries and propane tank. 

3.  Remove the Joey Bed.  If you remove the first 2 rollers on each side of the rail.  The unit will lift right out then you can remove the screws that hold the rail to the coach.  Push the tray out the drivers side.  Remove the first couple rollers on each side of the passenger rails and pull back and up.  It is out.  These are heavy.  2 people required.  Then remove the rail so you have a flat bay to work in.

4.  Break out your camera and start taking pictures.  You will also need masking tape for labeling and a wet vac.  As you start to remove hoses, etc. I used a wet vac to suck up all the water.  I wanted to keep everything as dry as possible.  Remove the burner unit by disconnecting the electrical and diesel lines.  I labeled everything so reconnect was easy.

5.  Start disconnecting the water hook ups, the engine coolant returns and the diesel connections.  Again, I can not stress enough labeling everything.

6.  Make sure your unit is drained.  Once the burner is removed, the drain is below the burner.  Disconnect the zone coolant lines.  Make sure you label them.

7.  Disconnect the electrical connections.  I made a hand drawn diagram of connections and labeled each wire.  The wires are also numbered so my drawing help on the reconnection.  Take a ton of pictures for reference later.  In my mind, you can never have to many.

8.  You should be all disconnected now.  No the hardest part.  There are 6 screws per side.  Front and back.  The back ones will require a mirror and a flash light.  Also a driver extension to reach down the back.  This will be tough and you will curse a lot (at least I did).  But you get them. 

9.  Once they are all out.  You are ready for the heavy lifting.  I used a crow bar and 2X2's.  Short blocks and long runs work great.  You will have slide blocks under each side to lift the unit over the metal cross member that sits behind it.  The goal is to get it into the bay on the wood 2x2's.  Once there, you just push.  I used a piece of 3/4 ply wood to get it out of the bay and on to a dolly.  This helps with the lip at the bay entrance and helps your back.  Once you are on the dolly.  The real fun starts.

10.  Take the unit in to your workspace.  The area must be dry and warm.  The heat transfer mastic takes at least 2 days to cure.  This is were your soldering skills come in.  The copper tubing connections will have to be removed from the water lines going into and out of the unit.  If you are not confident doing copper soldering, call a local plumber.  You also have to drill out the rivets on the case covering the boiler so it is fully exposed.  Again, photos' are great.

11.  In order to rewrap your boiler in new copper tubing, you will need 150ft of 1/4 inch copper water line.  I was only able to get it in 50' rolls so I connected it into one long spool by soldering on connections.  My unit had been frozen and about 80% of the pipe was burst on the top.  We saved $15,000 off the purchase price so I can't complain.  You will need to unwrap all the current copper pipe around the boiler.  Once my mastic was wet, the copper pipe release and was longer making contact with the boiler.  Once the copper pipe is off, you need to remove the loose pieces as best you can.  I used a concrete chisel and worked my way around.

Take note at this stage how the starting and ending copper tubing is attached.  You have to copy this.

12.  Once the boiler is cleaned off, you stand it up on it's end with a friend.  I set mine on a square work bench as you will be going in a circle.  And working height saves your back.  I found 2 tricks on re-wrapping.  Work from the bottom up, this saves the mastic from falling down, I only applied it as required on the way up.  Apply a good coating. 

Second, and this will make re-wrapping easy, work against the coil.  You going to want to follow the curve in the coiled tubing, don't.  It will not tension tight to the boiler.  Work again the curve,  this will cause the tubing wrap tight and create a new curve that will match your boiler.  Keep it tight.  The mastic will ooze out between, that is ok.  I counted the wraps on my unit before I removed the existing pipe.  You should be able to match the wraps, or at least close.  My first couple wraps were not tight enough before I discovered how to re-wrap.  I lost 3 wraps, only meant a re-adjustment of the tempering valve that sits under the burner.

Once you wrapped.  You have to leave it for at least 48 hours, depending on your humidity till it dries.

13.  Once the unit is dry, you just work in reverse.  I re-used my insulation and beefed it up with some reflective water proof insulation.

I am glad I did the repair.  Saved us $15,000 plus I know how my unit works now inside and out.  The cast iron boiler is really well built and solid.  Will definitely out live me.

Matthew

Re: Aqua hot Rebuild

Reply #1 –
That looks to be much larger than 1/4" in tubing. I checked with AH and was told mine has 141 ft. of 1/2" tubing.

Re: Aqua hot Rebuild

Reply #2 –
I agree that is 1/2" tubing for sure.
JohnH

Re: Aqua hot Rebuild

Reply #3 –
That tubing that's been split from freezing certainly makes one ugly picture. Congratulations on successfully replacing it!

Re: Aqua hot Rebuild

Reply #4 –
If you look in inside my vintage of unit, after the water intake and mixing valve, there is a reduced for my size tubing.  It reduces from 1/2 copper to 1/4 inch copper then back to 1/2 copper at the mixing valve.  I was surprised as well when I opened it.  The old is still sitting behind my garage in a bin.  I have to take it to recycling.

Matthew :)

Re: Aqua hot Rebuild

Reply #5 –
Quote from: Rob & Matthew –
If you look in inside my vintage of unit, after the water intake and mixing valve, there is a reduced for my size tubing.  It reduces from 1/2 copper to 1/4 inch copper then back to 1/2 copper at the mixing valve.  I was surprised as well when I opened it.  The old is still sitting behind my garage in a bin.  I have to take it to recycling.

Matthew :)

I wonder why yours is different than mine. Called Aqua Hot today and was told my model uses 141 ft. of 1/2" double walled copper tubing.

Re: Aqua hot Rebuild

Reply #6 –
Very Impressive Matthew! 
I remember your original post some time ago so it must be working good.  I have never heard of anyone doing this before.  I believe you are the first.
Is wrapping the copper the trickiest part-with the spring-back?
I imagine once you start you have continue until the other end is secured?
Thanks for the great write-up.

Re: Aqua hot Rebuild

Reply #7 –
My turn. Fresh water leak on my 1999 U320 Aquahot AHE100-01S. No money for a refurbished unit. Gotta go the po-boy route.
Drip had increased. Removed unit. Found pinholes in the 1/4" tubing wrapped around the tank. Debated and discussed back and forth... finally admitted I need to re-wrap the tank with new copper tubing. Patching pinholes would likely be a temporary fix since they are probably caused by internal corrosion. No way to know if it would last an hour, a day or a few years.
Found a couple of RVers that had tackled the job of re-wrapping theirs so with their info and encouragement here I go.
The heat transfer mastic source is www.chemax.com TRACIT-300.
Copper tubing is type L. Mine is 1/4" I.D.
In an earlier post Matthew had stated "this will make re-wrapping easy, work against the coil.  You're going to want to follow the curve in the coiled tubing, don't.  It will not tension tight to the boiler.  Work against the curve,  this will cause the tubing wrap tight and create a new curve that will match your boiler.  Keep it tight.  The mastic will ooze out between, that is ok.  I counted the wraps on my unit before I removed the existing pipe.  You should be able to match the wraps, or at least close.  My first couple wraps were not tight enough before I discovered how to re-wrap.  I lost 3 wraps, only meant a re-adjustment of the tempering valve that sits under the burner."

It took me a while to get over the fear of possible failure. Finally proceeded slowly on disassembly with pictures and notes. Ordering mastic tomorrow.
Wish me luck.
Bob

Re: Aqua hot Rebuild

Reply #8 –
Hawkeye,

When I did mine, I ran the copper with the direction of the curve without any issues, however, I tacked the copper to the tank so it will not move. I also cleaned the whole unit and replaced nozzle etc while I had it apart. Shark bite fittings are a great addition improving ease maintenance in the future in removing pumps etc. have fun with it. I will do a write up in the future.

Re: Aqua hot Rebuild

Reply #9 –
Hawkeye,

1 Gallon will be plenty of the 300. 600 is over kill and with the 300, you will be covered by the heat rating. Mastic is a mess to work with and does not stick while wet. As you wrap the tubing, fill in the gaps, most of it will run out, however, if you let it harden a little, its much easier. There is not much window when the mastic starts to set up. When done wrapping copper, you can just apply a thin coating over pipe and it will harden and stick to the pipe. I went with 100 feet and 50 feet so that I only needed one joint soldered for whole boiler. I used a shark bite connection on the pump side so it can be removed easily if need be.

I hope this helps.

Rob

Re: Aqua hot Rebuild

Reply #10 –
Looks like this.

Re: Aqua hot Rebuild

Reply #11 –
BTW,

The tubing is 1/2 inch around the boiler and reduced at the end connections. You can re-work these connection points for easy access later if need be, think a few steps ahead if possible.

Re: Aqua hot Rebuild

Reply #12 –
The pin holes in the copper tubing reminded me of something I read when using Reverse Osmosis water:  the RO water will leach out minerals in the copper and cause pinhole leaks.  I can recall some member(s) installing "whole house" RO systems that would fill their fresh water tank.  I never put these two together until reading this thread now.
Here's a webpage discussing it:
 Residential RO Systems

Re: Aqua hot Rebuild

Reply #13 –
As I understand it RO's filter out the bases and leave the acids in water hence the damage

Re: Aqua hot Rebuild

Reply #14 –
This is the exact thing that I have to do this winter. Just inspected mine tonight from a discovered leak a couple of weeks ago. Does it improve the heat transfer to put mastic on while wrapping the copper so there is some mastic inside the coils? Also, I was wondering if sharkbite fittings would be able to handle the heat through the copper lines as well as the general heating of the aqua hot box?

Great write ups from those going before. I truly appreciate the information being delivered. Helps take the fear factor out of it.

Thanks,
Larry

Re: Aqua hot Rebuild

Reply #15 –
Larry,

Shark bite fittings come with different heat ratings, use the correct one. I completely cleaned my boiler, then called the mastic MFG and asked if I could use a protective paint for this purpose without compromising the product properties. The answer is yes, I can use this product and this is used in many industrial applications. My unit works like never before and I really need to turn it down! One more thing worth mentioning is, when soldering connections where many small connection points are made, heat can damage the other connections. Where the pumps consist of many soldered joints, I would take the route less traveled, disassemble and re-solder all joints making 100 percent sure of no leaks from heat damage. Just my 2 cents. Remember that heat divides and becomes less heat from its source and should be our rule for heat ratings.

Re: Aqua hot Rebuild

Reply #16 –
You can always lightly clamp a vise grip or other pliers to the other joint to act as a heat sink so it won't get as hot.

Re: Aqua hot Rebuild

Reply #17 –
Quote from: ohsonew –
This is the exact thing that I have to do this winter. Just inspected mine tonight from a discovered leak a couple of weeks ago. Does it improve the heat transfer to put mastic on while wrapping the copper so there is some mastic inside the coils? Also, I was wondering if sharkbite fittings would be able to handle the heat through the copper lines as well as the general heating of the aqua hot box?

Great write ups from those going before. I truly appreciate the information being delivered. Helps take the fear factor out of it.

Thanks,
Larry

Larry - is yours a fresh water leak?

Re: Aqua hot Rebuild

Reply #18 –
So a new Aqua hot is 15K ? but what about just the boiler? Anyone price that out? Can you just buy that item ?
Either way, great job and ingenuity on the rebuild. I hope to never have to do that but just in case....
BTW what is double wall copper  pipe?

Re: Aqua hot Rebuild

Reply #19 –
I was quoted 10K for the boiler when I had my Monaco.