Aquahot Antifreeze Leak

[davidbrady]

I have an antifreeze leak at the top of my AHE-100-01S Aquahot. I spoke with the folks at AH and I read the Service Manual. Both agree that it's one of three things:

1) radiator cap
2) cracked expansion tank tube
3) filler neck solder joint

I ruled out (1) and (2). I'm going to use my radiator pressure tester to bring the tank up to 17 psi to see if I can identify the leak.

Anyone have any experience with repairing a leaky filler neck solder joint? I wonder if I can do it in place or if the AH needs to be pulled from the bus.

This is my second AH. I replaced the original back in '07 with a reman unit at the cost of $4K (after reducing $1K for the core). Argh...

[pgchin]

(04-03-2013 09:40)davidmbrady Wrote:  I have an antifreeze leak at the top of my AHE-100-01S Aquahot. I spoke with the folks at AH and I read the Service Manual. Both agree that it's one of three things:

1) radiator cap
2) cracked expansion tank tube
3) filler neck solder joint

I ruled out (1) and (2). I'm going to use my radiator pressure tester to bring the tank up to 17 psi to see if I can identify the leak.

Anyone have any experience with repairing a leaky filler neck solder joint? I wonder if I can do it in place or if the AH needs to be pulled from the bus.

This is my second AH. I replaced the original back in '07 with a reman unit at the cost of $4K (after reducing $1K for the core). Argh...

Hey Dave,
Another member of the community recently went through this. He pulled his out because the insulation blanket was soaked with antifreeze and that job is a bear to do. He also needed to redo his bays. IF you can get to the the rivets to drill them out either with a regular or side shaft drill and get the cover off, I see no need to pull Unless your insulation is soaked. IF it is, THEN you are going to have to pull it and do your usual Tim the tool man Taylor bilford 9800 upgrade job! Maybe Kurt H will chime in here since he is the man with experience and can give you first hand data and support of your project. In the past, you have ALWAYS been his "go to" guy.
PS if he's a bit "shy" or too busy with his engraving business and does not see this post, pm me and I'll give you his number and you can call him.

[Arcticdude]

I replaced mine recently. I'm not sure it's worth trying to do it in place. There also may be a rivit or 2 on the backside, that requires you to pull it at least loose to get those out to get the main cover off. Also, trying to get enough heat into the neck will require a pretty good heat source. I'm not sure I'd want that much flame inside the bus. FWIW, the "new" reman units are $7700 after the core!



I'll add the insulation is stuck to the cabinet, so it will come out with the cover, but the thermal mastic used to enhance transfer from the boiler to the water coil may also get in the way of fixing the neck.

[davidbrady]

Thanks guys, very much appreciated. I got in there and had a good look around. I think you're right John, it has to come out. The loop is pressed against the filler neck. To get a good solder connection a fair amount of conductive paste will need to be removed and the only way to do that is to remove the box from the bus. This will be my second time so it should be a little easier. So what's up with these early models? Why can't AH find a way to attach the filler necks reliably?

[Arcticdude]

My guess is the dissimilar metals between the barrel and the filler neck. Too much of a difference in expansion coefficients. If they'd build the whole thing out of stainless, it would be much better. But then they wouldn't have the "repeat" business!

[encantotom]

i have not heard of this issue being common on the aquahot in our newells.

most of us have the Aqua-Hot AHE-120-00x

This is a 431 series model with DUAL elements. This model was made just for Newell. This model has normal 1650 watt 110-volt element AND 4500 watt - 220-volt element. Newell also added thermostat that displays boiler tank temperature inside the coach.

many of the newell guys have been cautioned to make sure the ph levels are ok. have you checked that?

tom

[Bumpersbird]

[/font]

(04-03-2013 20:38)davidmbrady Wrote:  Thanks guys, very much appreciated. I got in there and had a good look around. I think you're right John, it has to come out. The loop is pressed against the filler neck. To get a good solder connection a fair amount of conductive paste will need to be removed and the only way to do that is to remove the box from the bus. This will be my second time so it should be a little easier. So what's up with these early models? Why can't AH find a way to attach the filler necks reliably?

David,

The filler neck is steel, the cap goes into a brass cup that has the ears the cap cams into, to hold it on. It is soldered on to the steel filler tube. You may be able to just torch it and the solder may take and solve your problem, then again it may not. There is very little structurally that can go wrong, the weak link is the cup for filler cap and I would speculate that has been a little money maker for Aquahot. As they claim there is no fix or service for anything inside the boiler area, I think that’s why they rivet it together instead of using screws. They don't want you in there, other than a catastrophic failure the only thing that is fragile is the cup soldered onto the filer neck. I bought a new one from Aquahot, but any parts supply house has these parts they are just stock radiator parts. I did completely rebuild my Aquahot, as far as I know nobody else went as far as I did, I did it because Aquahot wanted $9900.00 for a reman, and before they would ship it, they demanded that my old core be on their loading dock to complete the transaction. Not very good customer service IMO. Pulling this beast is a PITA if you do drain all fluids it will cut total weight by 1/2 down to 150 lbs+- drill out the rivets and lift off the cover, this should get you enough access to re solder the cup. You most likely will not be impressed with the insulation. It just pink spun fiberglass, like they use in between the studs in the walls of your house. The tech told me just run down to the big box store and buy some r-19 pink stuff. I used Cerra-Blanket used to insulate ovens and other industrial applications, I have lots of it if you need any. By the way Pete, nobody has ever accused me of being; "SHY", too funny

[Arcticdude]

Kurt,
What did you use to improve heat transfer to the copper coil from the boiler?

[Bumpersbird]

(04-04-2013 14:12)Arcticdude Wrote:  Kurt,
What did you use to improve heat transfer to the copper coil from the boiler?

I did not do anything. It is all original. The copper tubing and mastic were in good shape I left that alone, and if i were you I wouldn't mess with that unless you want a lot of headaches. There was a lot of discussion on this subject on the WOG forum a year ago. As far as I know no one knows what this mastic is and the idea of possibly replacing the coper with pex may work, it certainly would be easier, I think most people assume the mastic is for heat transfer, I don't. I think it's there to secure the copper line to the tank to keep it in touch with the boiler tank and to keep it from vibrating and wearing a hole in it

[davidbrady]

Hi Kurt,

Thanks for taking the time to register and to fill me in on your repair. I remember the magic and craftsmanship you worked on your aquahot. Is it working well for you?

So if I'm understanding you correctly it's not the filler neck to tank that gives problems, it's the brass cup to filler neck that typically leaks??? I'm imagining a steel neck that's around four inches in length and then a brass cup that's maybe half that length, and the brass cup is soldered to the top half of the steel neck. How does the steel neck attach to the tank? Is it welded or soldered? If the leak is at the cup to neck interface I may be able to get in there with a small torch...

In the newer Aquahot's they did away with the neck, cup, and cap. All they have is a hose bib that runs to an expansion tank. This elimination of the cap might also be an option, but in this case an external deaeration tank would need to be placed somewhere and I suppose it would need a pressure relieving closed system radiator cap, similar to the way our Series-60's are set up.

Tom, this may be why you don't see this issue. Does the 431 have a cap, cup, and neck attached to the tank boiler?