Thermon HSX - Manual (Page 8)

Troubleshooting
The following information is intended to assist in maintain-
ing and troubleshooting a heat traced hot water system. The
primary goal of a heat tracing system is to provide an efficient
supply of hot water closer to the point of use than is possible
with a recirculated system.
Like many other systems installed in a facility, the successful
installation of a heat tracing system will require coordination
among several trades involved in the construction process.
Mechanical, electrical and insulation contractors must each
provide services that are critical to the proper operation of the
system.
Replace all damaged heating cable. Do not re-
connect power to cable that has been exposed
to excessive heat moisture. Failure to replace
damaged cable can cause arcing or fire.
Disconnect power to heating cable (turn off cir-
cuit breaker) when working on heat trace pipe,
or heat tracing systems.
CAUTION
Symptom - Water Not Hot Enough
Possible Causes Remedy
Water heater/mixing valve set point too low. ...................................Reset water heater temperature level, maximum temperature 65°C (149°F).
No power to heating cable ..............................................................Check power distribution panel to ensure breakers are energized or have not tripped.
Splice connection missed during installation ...................................Using drawing and visual inspection, check to see if any splice connection has been
overlooked. This may be evident if one area of a heat traced circuit is "cold".
Compressed, missing or wet insulation ...........................................Replace missing or damaged insulation, ensure that pipe and insulation have not been
forced against other pipes to cause heat sink along its length.
Pipes were not properly insulated .................................................Ensure that insulation is per the table. Reinsulate where needed.
No heating cable installed in area ....................................................Verify that the pipe in question was scheduled for heating cable.
Ambient temperature too low ..........................................................Measure ambient temperature in interstitial space where the heat traced pipe is located.
If the temperature is below 22°C (71°F), the ambient is too cool. Raise the ambient
temperature.
Cable not powered at correct voltage ..............................................Verify the proper design voltage and compare with measured value at power connection
point.
Heat loss at temperature limiting valve ............................................In some TLV's heat loss can occur between the hot and cold inlets via the non return
valves. Check that dirt from system is not causing malfunction of the non return valves.
Supply and install filter screens at inlet to valve body.
Symptom - Water Too Hot
Possible Causes Remedy
Water heater/mixing valve set point too high ..................................Reset water heater temperature level, maximum temperature 65°C (149°F).
Pipes were not properly insulated ...................................................Ensure that insulation is per the table. Reinsulate where needed.
Ambient temperature too high ........................................................Measure ambient temperature in interstitial space where the heat traced pipe is located.
If the temperature is above 27°C (80°F), the ambient is too high. Lower the temperature
interstitial space.
Cable not powered at correct voltage ..............................................Verify the proper design voltage and compare with measured value at power connection
point.
Symptom - Circuit Breaker Tripping
Possible Causes Remedy
Improper electrical connection ........................................................Cable could be damaged or improperly connected. Visually inspected heating cable,
connections and terminations. Test cable with megger.
Maximum circuit length exceeded ...................................................Verify the length of the heating cable, including all cable located on tee splices.
Compare this length with the maximum circuit length and circuit breaker sizing chart.
Increase breaker size or add additional circuit if needed.
Piping/building is too cold during start-up ......................................The building and the water in the pipe must be greater than 16°C (61°F). Raise building
temperature or purge hot water lines.
Damaged power feed wire leading to power connection ................Disconnect heat cable at power connection and test power feed wires running back to
power distribution panel.
Faulty branch circuit breaker ...........................................................Replace breaker and energize heating cable.
CAUTION
Before calling your heat tracing vendor when things aren't go-
ing right, make a visual inspection; perhaps the thermal insula-
tion is wet, damaged or missing. Also, consider the possibility
that repairs or maintenance of nearby equipment may have
resulted in damage to the heat tracing or its power supply.
These are common causes of heat tracing problems, and they
are often overlooked. A number of other possibilities are listed
below, with their symptoms and remedies.
If at any time you feel that the heating cable has been dam-
aged, a dielectric insulation resistance test with a megohmme-
ter (megger) is recommended.
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