AERCO KC1000 Water Heater July 2011 - Manual (Page 41)

SAFETY DEVICE TESTING
5-3
5.6 INTERLOCK TESTS
The unit is equipped with two interlock circuits
called the Remote Interlock and Delayed Inter-
lock. Terminal connections for these circuits are
located in the I/O Box and are labeled REMOTE
INTL’K IN and DELAYED INTL’K IN. These
circuits can shut down the unit in the event that
an interlock is opened. These interlocks are
shipped from the factory jumped (closed).
However, each of these interlocks may be
utilized in the field as a remote stop and start, an
emergency cut-off, or to prove that a device
such as a pump gas booster, or louver is
operational.
5.6.1 REMOTE INTERLOCK
1. Remove the cover from the I/O Box and
locate the REMOTE INTL’K IN terminals.
2. Start the unit in the manual mode at a valve
position between 25% and 30%.
3. If there is a jumper across the REMOTE
INTL’K IN terminals, remove one side of the
jumper. If the interlock is being controlled by
an external device, either open the interlock
via the external device or disconnect one of
the wires leading to the external device.
4. The unit should shut down and display
INTERLOCK OPEN.
5. Once the interlock connection is recon-
nected, the INTERLOCK OPEN message
should automatically clear and the unit
should resume running.
5.6.2 DELAYED INTERLOCK
1. Remove the cover from the I/O Box and
locate the DELAYED INTL’K IN terminals.
2. Start the unit in manual mode and fire at a
25% to 30% valve position.
3. If there is a jumper across the DELAYED
INTL’K IN terminals, remove one side of the
jumper. If the interlock is connected to a
proving switch of an external device, discon-
nect one of the wires leading to the proving
switch.
4. The unit should shut down and display
DELAYED INTERLOCK OPEN. The
FAULT LED should be flashing.
5. Once the interlock connection is recon-
nected, depress the CLEAR button. The
unit should start.
5.7 FLAME FAULT TEST
1. Place the ON/OFF switch in the OFF
position.
2. Place the unit in the Manual Mode and set
the Air/Fuel Valve Position between 25%
and 30%.
3. Close the manual leak detection valve
located between the safety shut-off valve
and the differential regulator (see Fig. 5.4).
4. Start the unit.
5. The unit should shut down after reaching the
Ignition cycle and display FLAME LOSS
DURING IGN.
6. Open the valve previously closed in step 3
and depress the CLEAR button.
7. Restart the unit and allow it to prove flame.
8. Once flame is proven, close the manual leak
detection valve located between the safety
shut-off valve and the differential regulator.
9. The unit should shut down and execute an
IGNITION RETRY cycle by performing the
following steps:
(a) The unit will execute a shutdown purge
cycle for a period of 15 seconds and
display WAIT FAULT PURGE.
(b) The unit will execute a 30 second re-
ignition delay and display WAIT RETRY
PAUSE.
(c) The unit will then execute a standard
ignition sequence and display WAIT
IGNITION RETRY.
10. Since the manual gas shutoff valve is still
closed, the unit will shut down and display
FLAME LOSS DURING IGNITION following
the IGNITION RETRY cycle.
10. Open the valve previously closed in step 8
and depress the CLEAR button. The unit
should restart and fire.