AERCO SWDW68 U-Tube Double-Wall Heaters w/ECS - Manual (Page 48)

HE-
111 − TROUBLESHOOTING
Rev B Mar 2013 7-6
Table 7-1. TROUBLESHOOTING – HEAT EXCHANGER, continued
NO. FAULT INDICATION PROBABLE CAUSE CORRECTIVE ACTION
(Continued)
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.
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.
T8 Heat exchanger shuts
down below Hot Water
Output temperature. The Over-temperature Limit Switch is out of adjustment
or some component of the system has failed. Check the over-temperature Limit Switch setting per 4.3.2.
Inspect and repair or replace each component as necessary.
T9 Loud banging in heat
exchanger or in steam
piping - not to be
confused with the
normal clicking noise 1. Faulty vacuum breaker.
2. Lack of expansion capability in the hot water
system.
3. Insufficient shock absorbers.
4. No check valve in the condensate drain line.
5. Supply steam line is not properly trapped.
6. 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.
1. Check the vacuum breaker for faulty operation. If faulty,
replace vacuum breaker.
2. Insert an expansion tank in the Hot Water Output line near
the heat exchanger.
3. Insert shock absorbers (water hammer arresters) in both
the cold and hot water systems, as needed to eliminate
shock waves.
4. Lack of this check valve can enable 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.
5. Install a trap as indicated in Appendix C, Figure C1 through
Figure C5.
6. 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.