AERCO BMK 3.0 LN Nat. Gas June 2010 - Manual (Page 49)

SAFETY DEVICE TESTING
RESET BUTTON FOR MANUAL
RESET TEMPERATURE LIMIT
SWITCH
ADJUSTABLE
TEMPERATURE
LIMIT SWITCH
MOUNTING
PLATE
ON SHELL
HIGH LIMIT
Figure 6-2
Temperature Limit Switch Setting
Once the adjustable over-temperature switch
setting is approximately at, or just below, the
actual outlet water temperature, the unit
should shut down. The FAULT indicator
should start flashing and a HIGH WATER
TEMP SWITCH OPEN
fault message should
be displayed. It should not be possible to
restart the unit.
Reset the adjustable over-temperature switch to
its original setting.
The unit should start once the adjustable
temperature limit switch setting is above the
actual outlet water temperature.
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 (Figure 2-9) 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
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
reconnected, the INTERLOCK OPEN
message should automatically clear and the
unit should restart.
6.6.2 DELAYED INTERLOCK
Remove the cover from the I/O Box and locate
the DELAYED INTL’K IN terminals.
Start the unit in the Manual Mode at a valve
position between 25% and 30%.
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.
The unit should shut down and display a
DELAYED INTERLOCK OPEN
fault message.
The FAULT LED should be flashing.
Reconnect the wire or jumper removed in step 3
to restore the interlock.
Press the CLEAR button to reset the fault
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 valve position between 25% and 30%.
6-3