Lochinvar 100171920 K2 Motorized 3-Way Bypass Valve Kit for Low Temperature Protection

The Lochinvar 100171920 is an OEM motorized 3-way bypass valve kit designed for low return water temperature protection in Lochinvar commercial boiler systems. This kit provides automated bypass control to protect non-condensing boilers from damage caused by low-temperature return water.

How It Works:

The motorized valve continuously monitors and manages return water temperature by blending bypassed boiler water with cooler system return water. When system return water temperature drops, the valve opens to the bypass port, mixing hot boiler water with incoming system water to raise the inlet temperature. As return water heats up, the valve modulates back toward the closed-bypass position, maintaining stable and efficient boiler operation.

Key Features:

• 2-1/2" motorized 3-way valve with three-port (A, AB, B) configuration
• Power supply: 22–26 VAC or 28–32 VDC
• Maximum power consumption: 6VA at 26VAC full load
• Control signals: 3-wire, 3-point floating
• Actuator torque: 50 in-lb (5.6 Nm) at rated voltage
• 90° rotation time: 20–30 seconds from closed-to-bypass to fully open
• Defaults to closed-bypass position when there is no call for heat
• Compatible with Lochinvar PB/PF 502–2001 and CF/CH 402–2072 boiler models

Kit Includes:

• 2-1/2" motorized 3-way valve (part# 100208596)
• 18 GA white wire, 5 ft. (part# 100173331)
• 18 GA pink wire, 5 ft. (part# 100173335)
• 18 GA yellow wire, 5 ft. (part# 100173340)
• Instruction sheet (part# 100161070)

This genuine Lochinvar OEM replacement kit ensures reliable, automated low-temperature boiler protection, helping extend equipment life and maintain system efficiency. Refer to instruction sheet INS70023 for complete installation guidance.