AERCO SWDW68 U-Tube Double-Wall Heaters w/ECS - Manual (Page 45)

HE-
111 − TROUBLESHOOTING
Rev B Mar 2013 7-3
Table 7-1. TROUBLESHOOTING – HEAT EXCHANGER, continued
NO. FAULT INDICATION PROBABLE CAUSE CORRECTIVE ACTION
T2 Heat exchanger
overheats 1. Temperature Controller is indicating the wrong value.
2. Water is preheated too hot.
3. Termocouple is not installed in the water flow.
4. Leaking valve in by-pass line, if any, around the
Control Valve.
5. The Steam Input does not close.
1. Check by replacing the Temperature Controller with one
known to be correct.
2. Reduce the preheating to a temperature at least 10°F
below the desired Hot Water Output temperature.
3. Check to ensure that the thermocouple sheath does not
protrude more than ½“ from the compression fitting.
4. Maintain the valve to shut tight.
5. Check the instructions in Table 7-2, Item T11.
T3 Hot water outlet
temperature
fluctuates widely 1. The Control Valve does not close.
2. The Control Valve does not open.
3. There is a leak in either the inside or outside wall of
one or more of the heat exchanger tubes, as
indicated by a flow from the leak detection port.
4. The heat exchanger is being used at a rate higher
than its design capacity.
5. Steam pressure is too low.
1. Determine if the packing is too tight. See the instructions in
Table 7-2.
2. Determine if the packing is too tight. See the instructions in
Table 7-2.
3. Refer to Chapter 9, Section 9.2, and proceed as instructed.
4. Contact AERCO or your nearest AERCO Representative
for advice in remedying this problem.
5. Check the supply pressure gauge ahead of the Control
Valve. If the reading is low, adjust the steam supply
pressure to the required value. If there is a restriction in the
steam supply line, the gauge reading will drop excessively
when the heat exchanger calls for full steam, even though
the pressure seems to be normal when the load is light. If
the steam supply pressure is correct, the steam pressure
compound gauge reading should reach design pressure for
steam in the heat exchanger tubes as the Hot Water Output
temperature starts to drop. If it does not, check the
operation of the Control Valve.