Hydro Hot or Aqua Hot questions.

[Bob&AnnaMari]

Mbrain,

You have moved so fast on this it is hard to give you suggestions in time for them to be meaningful. You say you pressurized the system, but there are two distinctly separate fluid paths on your Hydro Hot. First, you have the outer fluid jacket which is the one with the antifreeze that circulates through all your radiators to heat your coach. This also surrounds the other fluid stream that heats the water for your coach. You never indicated whether the leaking fluid was water with antifreeze or just plain water. This would have been a real clue for trouble shooting.

You did mention that it only leaks when the diesel burner is on. In reality both the diesel and electrical units work in similar temperature ranges so just the temperature is probably not a factor. But, if you have an issue with the lines to the radiators and/or the fill neck as Jim (Coma) mentions, the quicker heat-rise (and corresponding pressure rise) of the diesel boiler could be an issue. It would have been easier to test these items when you had the boiler out, but you can still check for leaks when you put it back. I'm not sure about the Hydro Hots, but fill-neck issues on that same year Aqua-Hot units is not that uncommon.

The major difference between the Hydro-Hot (your unit) and the Aqua-Hot is the size of the fluid chambers. I doubt you would notice a difference when using the diesel burner, but when on electrical the recovery of the Hydro-Hot can lag behind usage if two people take long showers back to back. You only have five gallons in the Hydro-Hot and the electrical unit does not recover that fast. Moreover, on a true Aqua-Hot/Hydro-Hot system there may be other issues based on the more efficient radiators used in Aqua-Hot systems. But, your Beaver (as mine) does not have Aqua-Hot radiators. Beaver, instead, used a cheaper smaller unit for the radiator. Ours are fan-driven versus blower-driven units. So, I doubt you will notice any real difference between the heating capability between a Hydro-Hot and an Aqua-Hot.

Since it looks like your rig has spent some time in North Dakota, I would certainly check all the piping and tubing into and out of the Hydro-Hot unit before I concluded that, in fact, you need a new/rebuilt unit. These are a bundle of bucks and it would be a shame to spend all that money and just find out that it was tubing instead of the unit itself.

Bob

[Mrbrain]

It was glycol that was dripping. I will forward ur info onto the mechanic.. Thx bob and everyone else.. I will keep all I formed. Wow..what a headache.

[Mrbrain]

And we did find a cracked brass fitting at first and we thought we had the leak found but replaced the fitting and it still dripped along side the exhaust bug not as bad..

[Mrbrain]

The mechanic is worried about the controller. Will it work with a Aqua hot being a we may be replacing the hydro hot with a Aqua hot. Does anyone know if that could be an issue.

[Mr_D]

Originally Posted by Dr4Film

An older AH-100S or a 431/12 or the new 600 models all have the larger size boiler (16 gallons of coolant) whereas the 400 or 450D units are a downsized unit which I call the Baby Aqua-Hot that only hold about 5 gallons of coolant.

Dr4Film ----- Richard

Is there an "old" 600 unit? We have the 600D in our rig. If there is an old and new unit when did the new one start?

[Coma]

Originally Posted by Mrbrain

The mechanic is worried about the controller. Will it work with a Aqua hot being a we may be replacing the hydro hot with a Aqua hot. Does anyone know if that could be an issue.

Do you mean the Webasto Control or the thermostat?

[Dr4Film]

Originally Posted by Dr4Film

I would make sure that you don't get the "baby" Aqua-Hot that some coach manufactures have been using in the past.

An older AH-100S or a 431/12 or the new 600 models all have the larger size boiler (16 gallons of coolant) whereas the 400 or 450D units are a downsized unit which I call the Baby Aqua-Hot that only hold about 5 gallons of coolant.

Dr4Film ----- Richard

Originally Posted by Mrbrain

So Richard tell me why not the baby one.

Mrbrain,

There are a couple of reasons for having the larger 16 gallon coolant tank versus the 5 gallon one.

First, since there is not enough hot coolant to support both the room heating zones AND supplying hot water to the shower and sinks, whenever a significant amount of hot water is being consumed there is a switch that turns off any of the heating zones which means you won't have any heat while the hot water is being consumed. If that didn't happen you would end up with a cold shower.

Second, since the 5 gallon coolant tank cools off more rapidly due to either room heat or hot water usage the Webasto burner will run more often and longer to keep the 5 gallons of coolant at temp whereas the larger 16 gallon coolant tank can last much longer before the Webasto kicks in.

Originally Posted by Mr_D

Is there an "old" 600 unit? We have the 600D in our rig. If there is an old and new unit when did the new one start?

Mr-D,

If you review my original post which I included above you will notice that what I had stated was referencing the "new 600 model" as there might not be too many of the "old" 600 models around that are for sale.

Originally Posted by Mrbrain

The mechanic is worried about the controller. Will it work with a Aqua hot being a we may be replacing the hydro hot with a Aqua hot. Does anyone know if that could be an issue.

Mcbrain,

The controller for the Hydro-Hot is not the same controller used for the Aqua-Hot. They are completely different systems. You can see some of the differences especially the Electronic Controller by viewing this PDF file of a Hydro-Hot system.

If you were talking about the wall thermostat, those are fairly generic and will operate either system.

Dr4Film ----- Richard

[Mrbrain]

Well d. I sure hope that we don't have to replace this thing, save us slog of headaches.. Itis getting close to our first time trip also.. To az.

So wife is gettin excited..will keep u all informed Thx

[falconman]

I'm sure you've already checked this but I'll throw it out there just in case. Our AH developed a leak from the drain fitting under the burner. According to Roger Berke earlier units came with a plastic tube fitted to the tank, later models had all brass. I got the parts and install kit from him and all is well. I will add it was not easy to find the source of the leak as it to was dripping down the exhaust outlet. Good Luck.

[Mrbrain]

Ok people, first I want to thank all of you for ur help. The mechanics replaced both brass fittings, cleaned up the entire tank and welded another bead around all pipes they could. Reinstalled it yesterday , filled it with glycol, fired the baby up and let it heat up for 4 hours and no leak.. Yeeeehhhaaaa.. So looking like we r still on schedule to get the the h... Outta here January 1.. Wife is tickled pink. And I am feeling releived. Tomarrow the garage door company is installing the new overhead door in our other shop so I can permanently park this rig inside. We got the 50 amp box installed last week. So we can plug this monster in and keep it at least so nothing freezes till we leave. Wife get to put all her new goodies in. New towels,bed stuff, new kouriig coffee maker, oh jeeeze you name , she's got it covered. Wow.
Anyway I can continue working on that entry door closure that every beaver has problems with. Sound like they use a large rivet then grind it down, whatever I will get it fixed myself, I am not spending $180.00 for a new one. I am not crazy enough to do that.. Haha. So people. We r happy and all fired up for our first trip south for the winter. Wish us luck and God bless you all. Thx mr. And mrs. Brain

[Bob&AnnaMari]

Well I am glad you seem to have solved your problem. Do have a great trip.

[Mr_D]

Originally Posted by Dr4Film

Mr_D,

If you review my original post which I included above you will notice that what I had stated was referencing the "new 600 model" as there might not be too many of the "old" 600 models around that are for sale.

And if you review my question you will see I asked when they changed to the "new" ones.

[GreaTOne65]

MrBrain, my SIL fixed my door closer, with 4 prick punch dimples in the rivet. Said it was an old Machinist's trick! Don't know how long it's going to work but it is working to perfection now. The dimples were done about a 1/16 in, inside the rivets circle.

[Dr4Film]

Originally Posted by Mr_D

And if you review my question you will see I asked when they changed to the "new" ones.

I think Aqua-Hot in Colorado would be a better source to answer that question.

However, the owners manual has a copy write date of 2013. That really doesn't mean anything because the Installation manual has a date of 2011 and the Service manual has a date of 2012 and the parts manual has a date of 2014 so it is anyone's guess except for the experts at Aqua Hot.

Phone: 303-651-5500 
or 800-685-4298


Dr4Film ----- Richard