need manual, converting my cal spa to gas, raypak model 155A i think. that is all that comes up on raypak site similar to mine but only has parts list. need to know flow direction on back of heater. facing heater is flow IN on right or left? also need wiring diagram if available to trace out thermostat path. would like to use spa thermostat in heater tube if it is feasible. eliminating heater by replacmnt with pvc 2" and want to epoxy probe in pvc. any help appreciated.