Originally Posted by sailingdog
The amount of pressure on a boat's water system isn't that high, so the shape of the tank shouldn't be an issue.
.... But the rated PSI of the Pressure Relief Valve can be. I replaced the water pump that feeds my Isotemp water heater which from the obscene prices of the Isotemp I saw when I had my issue must put it at the 'top of the line'. As long as you don't do what I did... which was blindly or dumbly if you wish, just pick out the 'best' / highest PSI pump I could find without checking the 'fine print' in the water heater manual for the Max PSI allowed. I don't remember the exact numbers off hand but it was something like - Water Heater max allowed PSI was 47 and I fed it with a 50 + PSI pump. The relief valve handled it for a while summer before last but then it started 'hammering' - release-hold-release-hold into the drain hose making a horrible racket. Looking back on all the things that went on that spring I think the valve 'took it' for a while because I had a very small slit in a hose elsewhere that finally blew. After that there was no stopping the hammering until I read the fine print in the manual ...... duh.... and re-replaced the pump with a 45 PSI pump. Problem solved.
Wickford/Narragansett Bay RI
Last edited by christyleigh; 11-04-2008 at 01:27 PM.