AERCO BMK 2.0 LN Nat. Gas for Mass. only - Manual (Page 47)

SAFETY DEVICE TESTING
VFD
ADJUSTABLE
TEMPERATURE
LIMIT SWITCH
MOUNTING
PLATE
RESET BUTTON FOR
MANUAL RESET
TEMPERATURE
LIMIT SWITCH
SEE
DETAIL “A”
DETAIL “A”
FRONT VIEW
Figure 6-2
Temperature Limit Switch Setting
6.6 INTERLOCK TESTS
The unit is equipped with two interlock circuits
called the Remote Interlock and Delayed
Interlock. Terminal connections for these circuits
are located in the I/O Box (Figures 2-9 and 2-10)
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 jumpered (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.
6.6.1 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 and set
the firing rate 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
reconnected, the INTERLOCK OPEN
message should automatically clear and the
unit should restart.
6.6.2 DELAYED INTERLOCK
1. Remove the cover from the I/O Box and
locate the DELAYED INTL’K IN terminals.
2. Start the unit in the Manual Mode at a firing
rate between 25% and 30%.
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,
disconnect one of the wires leading to the
proving switch.
4. The unit should shut down and display a
DELAYED INTERLOCK OPEN fault
message. The FAULT LED should be
flashing.
5. Reconnect the wire or jumper removed in
step 3 to restore the interlock.
6. Press the CLEAR button to reset the fault.
7. The unit should start.
6.7 FLAME FAULT TESTS
Flame faults can occur during ignition or while
the unit is already running. To simulate each of
these fault conditions, proceed as follows:
1. Set the ON/OFF switch to the OFF position.
2. Place the unit in the Manual Mode and set
the firing rate between 25% and 30%.
3. Close the manual gas shutoff valve located
between the Safety Shut-Off Valve (SSOV)
and the Air/Fuel Valve (see Figure 6-3).
6-3