Pressure Switch | Current Models

The 4163P-EW Pressure Switch is the heater flow-sensing switch for current-model Arctic Spas — plastic body, 1/8" MPT connection. It sits on the heater and tells the controller whether water is actually flowing through the heater chamber; without its OK, the controller locks out heating to protect the element from a dry-fire.

When you'll need to replace it: the tell is an FLC ("flow check") error code on the topside that doesn't clear after a filter clean and pump check. Pressure switches fail from corroded contacts, a stiffened diaphragm, or cracked threads — and the switch is cheap, so it's the first swap before suspecting the heater itself.

Will this fit my spa? Yes, on current-generation Arctic Spas. Older spas take the Model 3902 Pressure Switch; Arctic Spas swim spas take the 4035P Swim Spa Pressure Switch. Bring the old switch to one of our three Ontario showrooms for matching if you're not sure.

How to install: drain below the heater, unscrew the old switch from its 1/8" MPT port, Teflon-tape the new threads, hand-tighten, reconnect the two spade terminals, refill and confirm the FLC code clears.