As part of my weekly black tank flush ritual, I also check the AquaHot expansion tank level. After noticing no change for the last couple of weeks I decided to take a closer look. I found the hose had failed at the boiler connection. This was quite suprising as this installation is just over a year old. I used the hose that was provided with the rebuilt unit. It will replaced with a quality neoprene hose. The original AH was found in the same condition when we purchased the coach. Additionally the boiler level was quite low. Three years later the unit developed a leak. Long story short, everyone with a AH should periodically check that the expansion system is actually operating and potentially avoid a very expensive replacement.
Good catch Bob,
The overflow hose needs to be air tight from the filler neck to the overflow bottle to work properly.
Plus the radiator cap will loose its function over several years. If suspect, just replace it with a 13 lb cap from any auto parts store. I really like the ones that have the pressure relieve lever in the top of the cap.
I was replacing my Aqua Hot tank cap yesterday (thanks for the idea, Rudy) and grabbed the overflow hose to check it out. It broke off right at the hose clamp. All dried out. I took it off and saw that it was 1/4" fuel hose. Should have been 5/16" and from what I understand, anti-freeze will cause fuel hose to deteriorate. Anyhow, I replaced it with 5/16" transmission tubing. Not sure if this is the original hose or not. Must have been tough getting that 1/4" hose on those 5/16" fittings though. Good thing to check for you Aqua Hotters.
jor