STP SERIES Install, Operation, and Maintenance Manual
SECTION 5: TROUBLESHOOTING
Page
78
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
defective.
3.12.
Water heater
shuts down at
or too close to
(above or
below) the
design outlet
water
temperature.
1. Over temperature limit settings or
Aquastat not properly set or defective.
1. Refer to adjustment instructions contained in Section 3.12. Replace
the defective parts as necessary.
A loud banging
noise in the
water heater or
water piping
(not to be
confused with a
normal clicking
noise made
during
operation).
1. Water return piping has not been installed
properly to allow the water return
circulation; the water return line is
restricted; or the water return check valve
is leaking or has failed.
2. Improperly sized or disconnected
expansion tank in closed loop piping
system.
3. Inadequate water hammer arrestors.
1. Rearrange the water return piping and inspect the valve for proper
drainage. Also check to make sure there is no restriction in the
water return line. Replace the check valve if it is leaking or has
failed.
2. Install the properly sized expansion tank in the closed loop piping
system as shown in Installation and Piping drawings in Section 6.3.
3. In order to avoid any shock waves, install water hammer
arrestors/shock absorbers in the hot and cold water systems as
needed. Also check for any trapped air in the domestic water
system.
Over-
temperature
sound alarm
occurs
frequently.
1. Automatic over temperature settings not
properly set or defective parts.
1. Check and readjust the over-temperature setting as necessary.
Refer to adjustment instructions contained in Section 3.12. Replace
the defective parts or thermocouple if defective.
Unable to clear
Over-
temperature
sound alarm
condition.
1. Automatic over temperature settings not
properly set or defective parts.
2. Defective thermocouple.
3. Control valve or VFD pump requires
calibration.
1. Check and readjust the over-temperature settings as necessary.
Refer to adjustment instructions contained in Section 3.12. Replace
the defective parts.
2. Replace the thermocouple if shorted.
3. Recalibrate the Control valve or VFD pump per instructions in
Section 3.5 or 3.6.
