by Rob Cox, February 20, 2011
Pool Heater Repair: Rear Header Replacement
I got an email from a pool owner in Texas who found himself in need of a heater repair due to a rare winter freeze recently. When things thawed out, Gary's Raypak RP2100 pool heater was leaking a good amount of water on the left side. I told him right away, "Heater header, it's like a manifold on the end of your heat exchanger. You need a new one. Gaskets, too."
After a hefty estimate on replacing a cracked pool heater header from his local pool service company, Gary decides to give this pool heater repair a try. Gary's Raypak heater, common on US pools, is similar to gas pool heaters made by Jandy or Laars, and the repair tips here could be used on most pool heater repairs.
Heater headers are a cap on the end of the heat exchanger, which is a set of copper finned tubes that the pool water gets pumped through. The tubes absorb the heat of the flames below, and the return header or manifold, as it's sometimes called, returns the water out of the exhanger and on to your pool.
The return header on this older model Raypak is made of Cast Iron. Brass heater headers are also available as an option, but are not as common. Most modern heaters now have migrated to the use of thermoplastic headers; Raypak is now using a plastic known as Capron. Whether your return header is plastic, brass or iron, they all bolt on to the heat exchanger with 6 or more nuts screwed onto sturdy bolts.
To repair your pool heater, and replace the return header:
1. Remove side access panel. There is no need to remove the top on the Raypak. Older Laars heaters however, do require that you also remove the heater top in addition to the side panel.
2. Remove the high limit switch (shown with wires in the picture at right), and the pressure switch siphon loop tube. Use care not to damage the wires or the soft brass fittings.
3. Remove the nuts from the throughbolts. Don't lose 'em!
4. Use a heavy, flathead screwdriver to pry the 10lb. return header from the heat exchanger.
5. Use a smaller, sharp flathead to pry off the old, round gaskets from around the tubes.
6. Scrape any rust from the mounting plate, and install new gaskets.
7. Bolt on the new return header, in a criss-cross pattern. Torque tightly.
8. Reconnect hi-limit switch and siphon loop tube.
9. Reinstall side panel.
Cast Iron and Plastic pool heater headers take very little time to crack. The expansion of ice can be a powerful force. I hope that you have not also experienced the need for this pool heater repair, but if you have, I sincerely hope that this post has helped to take some of the guesswork out of how to replace your own cracked return header on your pool heater. Simple hand tools are all that is needed. That is, besides a new pool heater return header. And Gaskets, too.