Of all the equipment on a pool pad, the heater is the one where a small leak becomes an expensive problem quickest. Water dripping onto a heat exchanger or into a burner tray does damage that a seal never would.
Check in this order
1. Union connections
Where the heater joins the plumbing. Easiest to check, most likely, and cheapest. If the o-ring is hard, flattened or nicked, replace it rather than tightening further.
2. Header and manifold o-rings
The headers cap the ends of the heat exchanger. Their seals see the highest temperature in the entire system and harden faster than anything else on the pad.
3. Pressure switch and sensor seals
Small threaded fittings with their own seals. A weep here is easy to miss and drips directly onto components you do not want wet.
4. Drain plugs
Especially after winterizing. Replace the seals rather than reusing them.
Why heater seals fail faster
Heat is the accelerator. Every 18°F rise roughly doubles the rate at which an elastomer ages. A seal that would last a decade at ambient can be brittle in a few seasons at heater temperatures.
This is a case where material choice earns its cost — see our material guide, noting that EPDM is outstanding in hot water while nitrile is not.
Do not run a leaking heater
Water on a heat exchanger corrodes it, and a heat exchanger is most of the cost of the heater. If you find a leak, shut the heater down until it is fixed. A few days without heat is cheaper than a new exchanger.
Before you reassemble
Seat every o-ring with a thin film of food-grade silicone. Dry rings pinch and take a set. Aqua Flex Food Grade Silicone Lubricant is what ships in our kits.
O-rings only. Never lubricate the polished faces of a mechanical shaft seal.
Beaver Island Parts Company is not affiliated with, endorsed by, or sponsored by any equipment manufacturer named on this page. All brand names, model numbers and part numbers are the property of their respective owners and are used solely to identify the equipment our replacement parts fit.