Pentair 400K Heater Manifold Internals (77707 0209) aquacal A self resetting hi limit sensor is A self resetting hi limit sensor is useful because it helps monitor unsafe temperature conditions and then returns to normal operation once temperatures fall back into an acceptable range The AquaStar ChemStar CH200 parts bag is designed for compatible feeder service work where a grouped parts package helps support maintenance or repair of the ChemStar assembly The Pentair 400K Heater Manifold Internals (77707 0209) are replacement internal manifold components for compatible Pentair 400 Helps support proper water flow through the heater assembly