Raypak Genuine OEM 140 Degree F Hi-Limit Control, 600893B

The Raypak 600893B is the genuine high limit temperature control for Raypak digital pool and spa heaters, a black epoxy bodied control rated at 140 deg F.

Why it matters

The high limit is the heater safety that watches outlet water temperature. If the water leaving the heat exchanger goes past the control setpoint, it opens the circuit and the heater shuts down. That protects the exchanger and the plumbing when flow drops or a thermostat sticks. Because it is a safety device, a heater will not run with a failed high limit, and a control that has drifted or opened permanently locks the heater out even when the pool is cold.

Before you replace it

Repeated high limit trips are more often a flow problem than a control problem. Check the filter, the valves and the pump before condemning the part. If flow is good and the heater still will not stay on, this is the control to change. Note the temperature rating: Raypak uses more than one, and only the 140 deg F part belongs where a 140 deg F control is specified.

Raypak fitment for this part is given as the 185B, 265B, 335B and 405B digital heaters, and a second Raypak listing gives the same part as 185B, 265B and 335B. Check your parts list against your model.