I have a new pump/heater installation. All are Pentair products - filter, a
new 1/2hp pump and a Minimax 100 natural gas heater, supplied as a kit from
a good pool dealer. Everything is working fine - very strong flow from the
pool, through pump, filter and heater, then back to the pool. Heater
ignites and stays lit, burns strongly. However, the water isn't getting
I noticed the 2" header on the heater includes a bypass valve. This is a
small plastic disc held in place between the two halves of the header by a
spring. The spring seems to me to be surprisingly weak, especially
considering how well the pump works. This was the first thing that came to
mind, so as a test I added a small spacer to the valve spring, effectively
increasing its compression slightly. It made no difference.
So, my questions are; how long should I expect the heater to be running
before I can tell there is heated water? I've waited a few minutes. Does it
take a long time for the heat to penetrate the water headers in the heater?
I would think a few minutes would be more than enough. Has anyone
experienced a pump that is just pumping too powerfully for the heater to be
effective with the volume of water? Is it common for the bypass valve to let
a lot of water bypass the heater (I still think this is the most likely
cause). Is it possible the heater headers are blocked (tho it's a new
Any help would be much appreciated... I'm running out of ideas! Thanks.