Hale SMR - Manual (Page 28)

Introduction
2-14 Stainless Max Series Pumps
As the pressure on the diaphragm increases beyond the set
point, the stem will move off its seat, allowing pump pressure to
push on the piston in the relief valve.
This causes the relief valve seat to lift allowing excess pressure
to dump back to the pump suction side. After the pressure
equalizes, the piston returns to the closed position.
An Amber indicator light on the PM control illuminates when the
relief valve is open.
Thermal Relief Valve (TRV)
The Thermal Relief Valve protects the pump from overheating.
(See Figure 2-16: “TRV System.”)
The optional TRV unit can be
attached to the discharge
piping either by flange mount-
ing or 1-1/4”NPT threaded
connection (38 mm for the
TRVM).
The valve monitors the tem-
perature of the water in the
pump. When the temperature
exceeds 120°F (48.9
° C), the
valve automatically opens and
depending on the installation,
discharges a small amount of
water either to the ground or into the water tank allowing cooler
water to enter. After the temperature returns to a safe level, the
valve closes.
The TRV produces a flow rate of up to 1 to 2 GPM (3.8 to 7.6
LPM).
TRV-L Kit
See Figure 2-16: “TRV-L Kit.”
The TRV-L kit includes a chrome panel placard with a warning
lamp, a lamp test button, and a pre-assembled wiring harness.
The light illuminates whenever the TRV is open and discharging
water.
An optional buzzer provides audible warning. The buzzer mounts
on the operator panel.
Figure 2-16: TRV-L Kit