We have a 25,000 gallon in-ground pool that was rebuilt this summer. During the winter and the idle time a small creature built a nest on the burner tubes of the Rheem 406A propane heater. We cleaned it out and blew other leaves and debris from the heater, but the heater blows back when when we try to light it. Technicians from the pool company replaced the burner tubes and everything appears to be clean and the pilot system seems to be sparking correctly, but it still tries to fire up a couple of times and then eventually ignites and blows back with flames belching out of the bottom access under the burners.
The heater is 10 years old and the technician said it's time for a new heater. I'm concerned that there may be further internal cleaning required, or better alignment of the pilot, but I have not disassembled the manifolds and tubes myself to examine them.
He said everything looks clean and I don't see any obvious rust or corrosion, and the pressure is good from the underground tank. Is there something else I should be looking for - other than a different technician - or is a new heater the logical solution?