HALE AP, Technical Manual

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C-4
C.2. TEMPERATURE CONTROL DEVICES
Hale temperature control devices consist mainly of TRVs which automatically protect your pump
from overheating that may be caused by deadheading or other low flow conditions. Minimizing
the need for operator attention to overheating during pumping operations, the TRV automatically
dumps a controlled amount of water to atmosphere (ground) or back to the tank. The TRV opens
when the pump water temperature exceeds the preset value of the relief valve, and then auto-
matically closes when the pump water cools. When ordered with indicator light option (TRV–L), a
visual warning lamp is lit when the TRV valve is open. The TRV–L combines the functions of water
bypass with an operator warning system.
C.2.1 TRV
The TRV (see Figure 55) protects the pump from overheating. The optional TRV unit can be at-
tached to the discharge piping either by flange mounting or 1- ¼–in NPT threaded connection
(38 mm for the TRVM). The valve monitors the temperature 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 allow-
ing cooler water to enter. After the temperature returns to a safe level, the valve closes. The TRV
will flow up to 1-2 gpm (3-7 Lpm). For repair information see Hale Service Bulletin (SB–160) and
PL729 on the Hale website (www.Haleproducts.com).
Figure 56. TRV
C.2.2 TRV–L Kit
The TRV–L kit (Figure 56) includes a chrome panel placard with a warning lamp, lamp test but-
ton, and a preassembled wiring harness. The light illuminates whenever the TRV is open and dis-
charging water. An optional buzzer provides audible warning. The buzzer mounts on the operator
panel. For repair information see Hale Service Bulletin (SB–160) and PL729 on the Hale website
(www.Haleproducts.com).
Figure 57. TRV–L