STP SERIES Install, Operation, and Maintenance Manual
SECTION 4: MAINTENANCE
Page
62
of
97
Diversified Heat Transfer, Inc.
•
439 Main Road
•
Towaco, New Jersey 07082
Rev-1
09/11/2019 PHONE: 800-221-1522
•
WEBSITE: www.dhtnet.com
STP Manual
3-WAY CONTROL VALVE REPLACEMENT INSTRUCTIONS
1) Follow Steps 1 through 6 of the shutdown procedure in Section 3.9 to take the unit offline
before attempting this maintenance procedure.
WARNING!
Boiler water or high temperature water present situations that can be
very dangerous
because of the high temperatures and pressures. To avoid possible injury or death, use
common sense and follow all accepted and recommended procedures when performing
installation, operation, and maintenance procedures.
WARNING!
TURN OFF/DISCONNECT ALL ELECTRIC POWER BEFORE ATTEMPTING ANY
MAINTENANCE PROCEDURE.
2) Assure that the energy source, water inlets, and outlets have been shut off; that the
pressure has been bled from the energy source hot water system; that the unit has been
completely drained; and that all components and surfaces have cooled.
3) Turn off the power and disconnect the leads to the valve.
4) Carefully break all connections to the control valve and remove the old valve from the
unit.
When installing the replacement valve, do not mount with actuator below horizontal position. It
is essential to maintain the specified minimum clearance above and to the side of the actuator
and/or electronics module for servicing, installing, and heat dissipation:
•
1/2-inch to 1-1/4 inches = 4 inches
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1-1/2 inches to 2-1/2 inches = 6 inches
Port "B" is sealed with the accessories supplied (blanking disk, gasket, and the nut) for
straight through 2-way operation.
NOTE:
Blanking disks are not available for the large flange models.
FIGURE 4-6: 3-Way Control Valve NPT Connection Components
PORT B
BLANKING DISK
GASKET
NUT