Lochinvar COPPER-FIN 497 - 2067 - Manual (Page 42)

42
5
Electrical connections
Remote mounting of a sensor
You must mount the outside air temperature sensor outside
the building. To mount remote sensors, follow the guidelines
below. Take care to correctly wire sensors to the unit. Erratic
temperature readings can be caused by poor wiring practices.
Twist the wires between the unit and the remote sensor. Turn
wires at least three or four turns per linear foot of wiring. This
provides common mode rejection of some types of electrical
interferences.
1. Do not route temperature sensor wiring with building
power
wiring.
2. Do not locate temperature sensor wiring next to control
contactors.
3. Do not locate temperature sensor wiring near electric
motors.
4. Do not locate temperature sensor wiring near welding
equipment.
5. Make sure good mechanical connections are made to the
sensor, any interconnecting wiring and the controller.
6. Do not mount sensor with leadwire end pointing up in an
area where condensation can occur.
7. Use shielded wiring to connect the sensor to the control
when the possibility of an electrically noisy environment
exists. Shielded cable is recommended on all cable runs of
more than 25 feet in length.
NOTICE
Ground the cable shield at the connection
to the boiler temperature control only. Do
not ground the shielded cable at the sensor
end.
To maintain temperature accuracy, sensor
wires should be at least 18 AWG, see Table
5C.
TABLE 5C
Remote Wire Connection
Wire Gauge Max. Allowable Length
12 GA 100 FT
14 GA 75 FT
16 GA 50 FT
18 GA 30 FT
Hot surface ignition system
Hot surface igniter and ignition control
module
This unit has one ignition module and one hot surface igniter.
Figure 5-11_Hot surface igniter
The igniter is extremely fragile, be very
careful when removing. A faulty or damaged
hot surface igniter MUST BE replaced with
a Lochinvar PLT3400 igniter. Do not use
general purpose field replacement igniters.
ƽ CAUTION
Hot surface ignition control module
Ignition Module Lockout Functions
The ignition module may lockout in either a hard-lockout
condition, requiring pushing of the reset button to recycle
the control, or a soft-lockout condition which may recycle
after an approximate five-minute waiting period. This soft-
lockout condition is intended to allow self-correcting faults
to correct themselves and permit normal operation. A typical
hard-lockout fault is a flame failure condition. An ignition
module that is in a hard-lockout condition may only be reset
by pushing the reset button next to the ignition control or the
“RESET” button on the diagnostic panel on the left end of
the unit. Upon a flame failure, the reset button is only active
after the control module has completed its post-purge cycle.
Turning main power “OFF” and then “ON” or cycling the
thermostat will not reset a hard-lockout condition. Wait five
seconds after turning on main power before pushing the reset
button when the ignition module is in a hard lockout. The
ignition module will go into a soft lockout if conditions of low
air, low voltage or low hot surface igniter current are present.
A soft-lockout condition will operate the combustion air fans
for the post purge cycle and then the ignition module will
pause for approximately five minutes. At the end of this timed
pause, the ignition module will attempt a new trial for ignition
sequence. If the soft-lockout fault condition has subsided or
has been corrected at the end of the timed pause, main burner
ignition should be achieved with the resumption of the normal
trial for ignition sequence. If the control sensed fault is not
corrected, the ignition module will continue in the soft-lockout
condition. If the electronic thermostat opens during the soft-
lockout period, the ignition module will exit soft lockout and
wait for a new call for heat from the thermostat. A soft-lockout
condition may also be reset by manually cycling the thermostat
or turning the main power switch “OFF” and then “ON” after
the control sensed fault has been corrected.
Installation & Service Manual