I just changed the ignition coil on my Aqua Hot. It went pretty well. The contacts on the old one were quite a bit askew from where they should have been and that may have contributed to my original misfire issues. Put the new one on and aligned the points with the gauge. Fired right up. All good.
Except... now it seems the circulating pump for the Aqua Hot loops is not working. It fires and heats up but no heat in the cabin. Low voltage fans run but only blow cold air. AND domestic water pump does not work either. I was going to just make sure the system was hot and when I run water it slowly gets low and the pump does not cycle. I checked the breakers behind the cover in the curb side bay. I assume the one marked Aqua Hot runs the pumps as well. They are both fine. Is it irony these are both are giving me fits or is there a common solution? Thank you in advance.
Under the Aqua Hot cover located on the face of the tank, there is a fuse for the pumps in the series of fuses above the clear zone relays. Check those fuses to see if one is failed. A failed pump fuse stops all zone pumps and no heat to any zone.
Fresh water pressure pump is not a part of the Aqua Hot heater. Mine has always worked fine so other than a failing pump, I have no idea to assist you. My pump is located in the passenger side bay just in front of the drive axle.
Yep, I just confirmed that I am an idiot. Water pump is working. It was noisy when I was checking and I got all frustrated. Long story short... domestic water pump works.
I will check those fuses today. Thank you!
Fuses are good. Pumps sound like they are running. They are also hot. Still no heat on any zone.
They are magnetic drive, tap on them they might be stuck.
All three of them stick at the exact same time? I can give it a try.
Could the check valves at each pump be stuck? Maybe try tapping on them to free up the flapper?
With pumps running, whack each check valve. Check for valve becoming hot.
If no heat yet, loss of prime is next suspect.
Fill coolant tank at radiator filler neck to lipping full. Install radiator pressure tester. Turn all pumps on and pump pressure tester to 15 lbs. Now check for coolant circulation, ie., heat in each zone.
Follow up? Do you have pump working now?
Not yet. Ran out of time today. Will work on it tomorrow. Thanks!
Was going to add that an air bubble in the line will cause the same symptoms.. Hence pumping the system to 15psi will help move the bubble.
If you don't have a pressure tester, one can be borrowed at your local auto parts store. I got one at O'Riley's. Make sure Aqua Hot is full to the top and your overflow tank is at the correct level.
John M.
Small town. No radiator test kits locally but I think I can rig one with a small air pump. Any idea where to buy the correct pink/red coolant off the shelf?
Your vintage heater uses 50/50 engine antifreeze. A gallon or two of just distilled water will do just fine.
That was my gut feeling as well. You da man Rudy.
Instruction (I actually read instead of looked at the pics) lol
Use an air compressor and blow into the overflow line into the aquahot until the relieve valve pops and that puts pressure on the tank so you wont need the coolant pressure kit ^.^d
Update with instructions from the manual.. ^.^d
Little confusion on my instructions so I am posting the copy of the manual where everyone should look up on there own (never assume).. ^.^d
Update:
Tapping on the pumps and relief valves did nothing.
I got 2 gallons of distilled water and borrowed (bought and return) a pressure test kit from Advanced.
Getting fluid into the hole is a pain. Sounded like it was really empty thus the loss of prime.
It took 2 gallons of water and I still cannot reach liquid 6 inches down from the top of the fill tube.
I park on gravel and looked under and did notice some fluid had drained out around the Aqua Hot exhaust penetration. And there is some in the pan under the unit.
I had it serviced last 12/9/19 but they only changed the mixing valve, put new clamps on the fuel lines and put on a new radiator cap. They would not have drained or lost coolant for this right?
The overflow has always been an inch or two above Cold Full.
Up until this last month or so, the inside heat was working great whenever it was on electric and when the diesel burner was firing.
So, either I have a coolant leak somewhere or it has been low and finally air locked. The fact that there is fluid under it tells me it is a leak. So, where is the likely culprit? Just tell me the whole thing does not have to pulled out...
the tempering valve is on the water side.
Correct. But I'm wondering what else was removed to get to it and how much stuff was pushed and shoved to do it. or if anything was removed that would have meant losing coolant. After reading more on here there are some suspect places to look and I am doing that. The dripping from around the exhaust penetration is my biggest worry right now.
Only part required when needed is the motor.. Nothing else.. No coolant of any sorts but does not mean a solder connection did not open.. or worse.. Your going to have to get in there and look around then go from there.
Update - Good news, bad news.
Good news:
Managed to get the pumps primed. That was the heat issue in the cab. Filled to the rim and pressurized to 15PSI. Fired her up and we have heat.
Bad news:
I have a coolant leak. The overflow line was so brittle at the outlet it broke off. I changed the entire line to the overflow tank. I hoped that was where I was leaking coolant. I had a leak come out of the underbelly where the Aqua Hit exhaust exits. I was hoping that was the most extreme downhill spot and all would be good. BUT after firing up the diesel burner I am getting a little white smoke (coolant burning off) under the Aqua Hot pan. And I am getting some white smoke around the underbelly exhaust as well as measurable drip (maybe one drip every 5 second when it is fired up). There is no perceptible white smoke in the exhaust itself, it is clear. I have examined all the pumps, manifolds and cannot find a leak in them at all.
So... what does that mean to my pocket book?
If the tubes are leaking in the burner, about 10 cb's is what I was quoted on my '96 Monaco. The tubes crack from heat if the coolant gets too low to keep them filled.
Talked with Rudy. He gave me some optimistic things to look at and think about. Will report back. After it stops raining...
Wonder if stop leak would help?
8 coach bucks to completely rebuild the aqua hot per Rudy plus shipping.
Not sure what all is replaced.
Once out of the rv its not to difficult to take apart but its basically a boiler tank so depending on what they do... If its just the exterior copper tube replaced and new mastic.. you can do it yourself for $1000-1500 (my guess)
You can use most of the old parts but I would replace the shut off valves and the Mixing valve parts while I had it out.
New insulation or a new blanket like I did... Next time I would really consider shut of valves above each motor for maintenance .. still thinking of adding them but I had an idea to help with hot water supply that I borrowed from IRV2 I will add later..
Don't be shy David, inquiring minds want to know ;D
Larry
So there is a guy on IRV2 that his Aquahot froze or whatever... Coolant side worked great but the fresh side was leaking... he ran a Flat plate heat exchanger in place of the waterside ... I had never heard of them and Looking at how they work they are pretty efficient so I stole the idea basics from him... On my water in I am going to put a small one in so that the water in the winter (or at all times if small enough and doesnt heat to hot in summer) so I can heat the water coming in to a warmer degree and that will help with the water demand for never ending hot water instead of the 1.8g we see in our aquahot... the hard part is the incoming water degree especially in the winter.... I am going to add this thing and maybe do a bypass also and see if my idea will actually work...
open to criticism here also.. jump in..
CBH16-13H - Alfa Laval CBH16-13H - 125,000 BTU/Hr (Domestic Water) CB16... (https://www.supplyhouse.com/Alfa-Laval-CBH16-13H-125000-BTU-Hr-Domestic-Water-CB16-Brazed-Plate-Heat-Exchanger-13-Plates)
Using a plate exchanger is an innovative ideal. We use them in our process units and they are very efficient at heat transfer. I am interested in the outcome.
David, what am I missing?? What is used to heat the water in the exchange? I downloaded the brochure and I see how it would exchange from one side to the other, but what is the heating element? What am I not seeing? If this is viable, it could save me a lot of effort on rebuilding the AH.
Larry
coolant
Either from the engine/engine preheat or the furnace? Interesting, but it would require one of those 2 to be running, correct? If so, when running the furnace for heat, would it also be able to supply enough heat for the hot water or would both suffer?
Larry
Since coolant is running in opposing channels in the exchanger which could leak and co-mingle, you would want it to be a non-toxic coolant.
Could happen.. very doubtful
For those following snap disc thermostats here is a better idea as they come in different degrees
This might be the fix all on the thermostat questions
Given some time I am amazed at what I can find sometimes on the internet :))
Here is where Rob&Matthew rebuilt their aqua hot years ago.
John M.
Aqua hot Rebuild (https://www.foreforums.com/index.php?topic=28387.0)
David, that is basically the same type heat exchanger that is used in a high efficiency boiler. The problem we had was the heat exchanger did not have a user friendly way to remove mineral deposits from the water. I would recommend putting in extra ports with valves so you could easily fill it with white vinegar once a year let set for a couple of days then flush. They work great as long as they are clean inside.
Just my 2 c worth
Chris
Was going to add valves at each port so I can remove if necessary. not set in doing yet so still working on it in my head
Maybe this might be thought provoking. Consumer reports today had a report on using what we have used vinegar for. They are saying bad things about using it where it will come in contact with rubber, some metals.
So?
Maybe dishwasher cleaner would have a better line remover. They mention it in place of vinegar.
Just sharing.
John thanks for pulling up the link. That is the posting that I remember. I'm always amazed by the amount of vital information available on the forum and the willingness of its members to help find and share their knowledge. Just like Google knows all, it seems like when something is mentioned, someone here finds the right make, model or part # to help one another out.
Larry
Coastal Builder. Any updates on your Aqua Hot?
OK, I called Aqua Hot yesterday. I was trying to find out what diameter, length and type of copper tube I need to buy in order to redo my fresh water system. The tech I talked with said he couldn't give me specific information on the unit because they hadn't made this style in 18 years (possibly before he was born from the sound of his voice). He was pretty certain that it took 50' of 1/2" copper tube to do the job. It also didn't matter if I used type K or type L copper tube, it just needed to wrap tight on the boiler. How disappointing that this is the tech advise available. Evidently it isn't important to even try to look up the information for the general public who own an older unit, which doesn't bring in thousands of dollars for the company.
I'll do my own research on this forum and get much more accurate, friendly results.
End of rant.
Thanks to all the forum members for their help and listening. And an extra big thank you to Rudy for taking the time to answer some questions on the phone. Truly a gentleman and a scholar. I hope to make it down that way to meet Rudy in person someday, and when I do, lunch is on me ^.^d
Larry
The link John Morales put in the response above has the info I believe..
One other thing when you get to it..
When bleeding the system.. make sure you have the coach level to push the air out.. you will have issues if its not level..I can tell from experience..
That might be interesting. The driveway is too steep to get completely level. I can get close but no cigar .
Larry
I have not done anything yet on the AquaHot. It fires up great. It has sat for maybe 3 months now. I have fired it 3 or 4 times in that time and no problem. No white smoke in the exhaust. I do not have gallons of fluid under the coach. I got a new scope and can see inside. Pretty cool actually being able to look inside. The fluid is low but is above all the inside parts. It measures 7 inches from the TOP of the radiator cap tube to the coolant right now. The neck of the fill tube is really rusty and nasty. But I can't get a good look up at it after I go past it. I wonder if it's the neck issue I have read about. Still grasping at straws not to get a new or rebuilt unit. I could add 2 gallons a week for years for what it would cost to rebuild/replace.
Coastalbuilder. I would add fluid to the radiator fill neck. When it heats and expands it should go into the overflow tank. Inside the main tank are tubes running through the hot water solution for the engine preheat. When I rebuilt mine, the neck was highly corroded. I cleaned it up and got all the scale out of the tank. You really should locate where the leak is coming from to avoid moisture through the exhaust hole where it is possible for it to accumulate in the layer of foam between the fiberglass floor and bottom of the coach. The water could seep to the frame members, that would be no bueno.
Larry
Depending on how far down into the tank the filler neck is rusted you might be able to replace that. Call Rudy, he might be able to help you with a fix. I have a couple friends who did that, they cut off the old filler neck and replaced it with a rubber hose and new neck.
The Roger Berke Fillier Neck Kit is a 30 minute soluton to a leaking radiator cap filler neck leak. Once installed, you are done with that problem.
PM me with your phone if this is of interest to you.