TX Series Installation, Operation, and Maintenance Manual
Diversified Heat Transfer, Inc.
439 Main Road, Route 202
Towaco, New Jersey 07082
Page
24
of
33
Phone: 800-221-1522
Website: www.dhtnet.com
SECTON 6.2: TROUBLESHOOTING
The following table summarizes the problems that may be encountered over the life of a DHT TX Series
Water Heater, and the procedures to remedy those problems.
SYMPTOM
PROBABLE CAUSE(S)
REMEDY
Entire System is OFF
1.
External power supply
disconnected or ON/OFF
switch failed/OFF.
1.
Check to make sure service switch/fuse is ON and
there is power supply available. Replace the ON/OFF
switch if faulty.
Unit is not heating
the domestic water
(no hot water present
at the faucet).
1.
Isolation valve(s) is/are
closed.
2.
Aquastat is not set properly.
3.
Boiler is not operational.
4.
Boiler feed circulation pump
malfunctions/failed.
5.
The heat exchanger coil is
scaled.
6.
Boiler water or domestic
water inlet strainer clogged.
7.
Electrical power supply is
disconnected or ON/OFF
switch failed/OFF.
8.
Zone valve (if utilized) is
closed.
1.
Check to make sure isolation valves on both boiler
and domestic water piping are open.
2.
Check the set point settings on the aquastat. Readjust
the set point settings if below the required
temperature. Repair or replace aquastat if faulty.
3.
Start the boiler and refer to boiler startup or
installation instructions if needed. Check to make sure
boiler main service switch/fuse is ON and electrical
power supply is available.
4.
Check the power supply and inspect the circulation
pump for proper operation. Repair or replace the
circulator if not functioning properly.
5.
Clean the heat exchanger coil per instructions. Call
DHT or your authorized representative for instructions
on repair or replacement if necessary. Also ensure the
water quality levels are within the allowable limits.
6.
Blowdown and clean the strainer.
7.
Check to make sure power switch is ON and there is
power supply available. Repair or replace if necessary.
8.
Check the power supply and inspect the zone valve for
proper operation. Repair or replace if necessary.
DHW supply
temperature is too
high water too hot at
faucet).
1.
Aquastat is not set properly.
2.
Boiler feed circulator does
not deactivate.
3.
Improper system piping.
1.
Check the set point settings on the aquastat and
readjust if set higher than the required temperature.
Repair or replace aquastat if faulty.
2.
Check the circulator on/off temperature settings and
electrical wiring. Inspect, repair and replace the relay
switch or aquastat if not functioning properly.
3.
Check to make sure water heating piping and
components are installed in accordance with
instructions in Section 4.2.
Water heater is not
able to maintain the
required temperature
at the rated capacity
or slow recovery.
1.
Aquastat not set properly.
2.
Boiler water supply
temperature is low.
1.
Check the set point settings on the aquastat and
readjust if below the desired temperature setting.
2.
Check to make sure the boiler water inlet
temperature gauge reading is equal to the design
conditions. Readjust the boiler supply water
