I moved into a rental home that we're in the process of purchasing. We have a pool with attached spa. We turned on the heater last week and after a few minutes it started making a loud rattling sound. It sounds like a bolt or something is trying to get through the system. I took the cover off to inspect the heat exchanger. It looks ok to me (not saying much). After some more testing, it sounds like the noise is coming from the header. The header is leaking between each of the bolts across the top. I ran the heater with the suction coming from only the spa and from only the pool thinking maybe it wasn't getting enough water flow from one or the other. Same results from both.
So, I know the header gasket needs replaced. Could this cause the problem?
Or, is it more likely to be the bypass flow valve inside the header. I haven't removed the header yet because I'll have to remove the gas line as well. Also, when I do remove the header, do I have to remove it from the inlet/outlet lines, or can I just leave it attached and push the heater away from it. Make sense?
There is no bypass valve on the inlet/outlet pipes.