STP SERIES Install, Operation, and Maintenance Manual
SECTION 3: OPERATION AND CONTROLS
Page
30
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
3.9 UNIT SHUTDOWN PROCEDURES
All maintenance procedures require the water heater to be properly shut down. Follow the
instructions below in order to shut down the STP Series unit:
UNIT SHUTDOWN PROCEDURE INSTRUCTIONS
1. Close all valves in the energy source inlet line (boiler water or high temperature water).
2. Turn off all power to the electric control.
3. When possible, relieve the pressure from energy source line (boiler water or high
temperature water), between the shutoff valve and the unit.
4. Wait 5 minutes or until dial thermometer starts dropping. Close all remaining valves in the
system in this order.
a.
Hot water outlet line
b.
Cold water inlet line
c.
Boiler/high temperature water return line.
5. After the system has cooled, drain the unit by opening the heat exchanger drain valve
and holding the relief valve in the open position. This will prevent the formation of a
vacuum and increase the drainage flow.
6. Proceed with the required maintenance or repairs.
7. After performing the required maintenance or repairs, return the unit to operation by
following the startup procedures described above in Section 3.8.
