AERCO SWDW68 U-Tube Double-Wall Heaters w/ECS - Manual (Page 44)

HE-
111 − TROUBLESHOOTING
Rev B Mar 2013 7-2
Table 7-1. TROUBLESHOOTING – HEAT EXCHANGER
NO. FAULT INDICATION PROBABLE CAUSE CORRECTIVE ACTION
T1 The heat exchanger
does not maintain the
required temperature
at rated capacity. 1. The Control Valve does not open.
2. 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.
3. Recirculating pump failure.
4. The heat exchanger tubes are scaled up.
5. The heat exchanger is being used at a rate
higher than its design capacity.
6. Steam pressure is too low.
7. Condensate is backing up into the heat
exchanger because of a restriction in the
condensate drain line.
8. The condensate return piping has not been
installed so as to enable the condensate to
drain freely by gravity, and/or the condensate
check valve leaks or has failed.
9. Thermocouple is not installed in the water flow.
10. The Temperature Controller reads wrong.
1. Check the instructions in Table 7-2.
2. Refer to Chapter 9, section 9.2, and proceed as instructed.
3. Proceed as follows:
a. Check input power to the recirculation pump.
b. Check the temperature of the copper tube above the pump.
It should be the same as the outlet DHW temperature. If
cold, repair or replace the pump, as needed.
4. Contact AERCO or your nearest AERCO representative.
5. Contact AERCO or your nearest AERCO representative.
6. 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 the steam supply line is restricted, 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.
7. Contact AERCO or the nearest AERCO representative for the
trap size required and make the necessary correction.
8. If necessary, rearrange the condensate return piping to permit
condensate to drain freely from the heat exchanger connection.
Inspect the condensate check valve and replace it if it is leaking
or has failed. Also, ensure that there is no restriction in the
condensate drain line.
9. Check to ensure that the thermocouple sheath does not
protrude more than ½“ from the compression fitting.
10. Check by replacing the Temperature Controller with one known
to be correct.