Hi,

Thanks for the reply. I'm not sure your reply makes sense, because as far as I can tell, all current-technology pool heaters use PVC pipe and connections. I've looked at a couple of friends pools with newer heaters. The ones I've seen use something called a "hi-temp union" to join the PVC to the heater itself - no "header" required.

As an example, I checked one current-technology pool heater, the Pentair Master-Temp. Its installation instructions say the following: "Two inch PVC water piping connects directly to the manifold/header on the heat exchanger using 2" PVC slip unions provided with the heater. The outer manifold remains cool; no heat sinks are required."

Plumbing references say that the maximum working temperature of standard schedule 40 PVC is 140 degrees. I know that even my 30-year-old Teledyne doesn't heat the water to anywhere near that close - 105 degrees max. However, the headers at the heater do get quite warm to the touch - not exactly sure how hot (gonna take out my infrared thermometer and power up the heater soon). But it seems like 18 inches or so of copper pipe leading away from the header should dissipate the heat from the heater, leaving only the heat from the heated water, which should as I said only be around 105 degrees. I can then solder a threaded coupler and use a high-temp union. According to some references I found, most hi-temp unions are made of Noryl plastic, which is stable up to boiling-water temperatures. So even if the copper pipe is 120 degrees, the hi-temp union can take it and transition to the PVC on the other side of the union.

I also know that schedule 80 PVC is stronger and so a threaded connector to, say a copper threaded coupler would be less susceptible to leaks over time. I have a schedule 40 threaded coupler connection from the pump to the current filter and it has cracked over time. A few extra bucks in stronger materials can go a long way in preserving the longevity of connections.

But all that being said, thanks for the reply. As of right now, I'm going to plan on doing the above - leave 18 inches of copper and add a threaded coupler and high-temp unions to go to the new PVC on the new filter.

Thanks again,

Ron