It happens all the time. Due to poor water balancing in a commercial spa, the water ate the heat exchanger and is filling the combustion chamber. the customer said he heard loud rattling when he got to work and shut it off immediatley. When i got there the heater ran for about 20 mins and shut off at some point when i went outside to the truck to find the trouble code LED on the control board, AFS. I checked the blower (working) and went to take off the intake screen to check for blockages when suddenly the connection between the blower and combustion chamber started leaking water.
Most people with a history of poor water chemistry will just end up buying a new heater due to definite hassles down the road but this customer would like to replace the heat exchanger. I tore one of these heaters down a year ago and it took me about 2 hours. What is the quickest way to swap this out?