Hydrohot boiler antifreeze leak

[Bryan Beamon]

We have used 2 gallons of boiler antifreeze in the last month with no evidence of fluid leaking at any heat exchangers or at the radiator cap or at the plastic tube connecting the recovery tank. Also pulled the diesel burner out along with the burner chamber to check for any evidence of fluid dripping to no avail . The fluid leaks are continual if we are using the diesel or electric or furnace. The coolant drops 1 inch per day consistently .Currently we are using only the heat pumps for heat and electric on the hydro hot and still dropping fluid levels 1 inch per day. I also dropped the panels under the coach between the frame rails to check for fluid leaks. No evidence of fluid in the insulation to rule out a pin hole in one of the internal coils. The diesel burner runs clean with no smoke . Any other ideas would be helpful. Thanks

[Frank Bergamo]

Bryan,

Check the overflow tube at the boiler filler neck. If it is leaking there it will run down around the boiler insulation, absorbing the fluid. The plastic tubing deteriorates from the heat of the boiler. Try tightening the clamp and then run, checking for fluid leaking from connection. You may also have to replace part of the tubing if tightening clamp does not solve problem. Also, the filler neck may be leaking where it connects to boiler, leaking down into insulation. That’s where I would I would start. Hope this helps.

[Eric Maclean]

Bryan
It might be time to put a pressure tester on the boiler and look for the leak .
Another possibility is the engine coolant loop if it has a hole in the loop inside the boiler it may be transferring boiler antifreeze into the engine cooling system because the two systems are pressurized if the boiler has more pressure than the engine as would be the case if the boiler was hot and the engine was not then the coolant could be migrating into the engine cooling system.
Check to see if the engine coolant level is increasing

Eric

[Bryan Beamon]

Frank and Eric , thanks for the advise. Will post final solution

[Bryan Beamon]

Wanted to close the loop and what the problem was with our Hydrohot. The leak finally showed up dripping from the outside of the exhaust which indicates a crack in the copper tubing. We are pursuing a rebuilt or new 450d replacement . It took a month of leaking to show up.

[Steve Huber Co-Admin]

Bryan,
Not clear to me why you diagnosed a copper pipe crack. Where near the exhaust is it leaking and can you id the leak point inside the unit? Just asking as a new/rebuilt unit is not cheap.
Steve

[Bryan Beamon]

Steve, in checking with 3 reliable sources they indicated the diagnosis. I did not pull the top cover off the back half of the unit.

[Frank Bergamo]

Bryan,

I am with Steve on this one. Any leak will migrate down to the lowest point, the exhaust pipe, before dripping off. Before spending a boatload of money, you need to visually see where the leak is originating from. Then you can decide if unit needs replaced or repaired. Hope this helps.

[Frank Bergamo]

Here is the 450DE service manual. Pages 9,10, and 11 show the plumbing layout. Should be able to identify leak with a little effort. https://www.aquahot.com/files/service_manual/450-DE2%20Service%20Manual%20Rev%20C.pdf  Hope this helps.