AERCO SWDW68 U-Tube Double-Wall Heaters w/ECS - Manual (Page 46)

HE-
111 − TROUBLESHOOTING
Rev B Mar 2013 7-4
Table 7-1. TROUBLESHOOTING – HEAT EXCHANGER, continued
NO. FAULT INDICATION PROBABLE CAUSE CORRECTIVE ACTION
(Continued) 6. No check valve in the condensate drain line.
7. Condensate is backing up into the heat exchanger
because of a restriction in the condensate drain
line such as an undersized or faulty trap.
8. The condensate return piping has not been
installed so that the condensate drains freely by
gravity and/or the condensate check valve leaks or
has failed.
9. Recirculation pump is malfunctioning.
6. Lack of this check valve can allow condensate
― and live
Steam, if present
― to be drawn back into the heat
exchanger from the condensate line. This can result in a
high back pressure, water hammer, and, if live steam is
present, over-heating. Install a check valve in the
condensate drain line as indicated in Appendix C,
Figure C1 through Figure C5.
7. Check 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 check valve and replace it if it is
leaking or has failed. Also, check to make sure that there is
no restriction in the condensate drain line.
9. 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
required.
T4 Insufficient water flow
rate through the heat
exchanger 1. Cold Water Input pressure is low.
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. Check valves may not be fully open.
1. Check the pressure to the heater and correct, if necessary.
2. Refer to Section 9.2 and proceed as instructed.
3. Verify that the check valves on the CW and DHW sides are
fully open.