Install Instructions

Page 36
LAARS Heating Systems
Outdoor Reset Functions -
The next four lines in the display are used to set up the
Outdoor Reset functions:
• Outdoor Reset Enable/Disable - Note: This function
can be Enabled/Disabled only by a factory trained
technician.
• Low Water Temperature - Use the Up- and Down-
Buttons to select the function, use Up- and Down- to
select the new value, then press the round OK button.
• Maximum Outdoor Temperature - Use the Up- and
Down-Buttons to select the function, use Up- and
Down- to select the new value, then press the round OK
button.
• Minimum Outdoor Temperature - Use the Up- and
Down-Buttons to select the function, use Up- and
Down- to select the new value, then press the round OK
button.
For a complete explanation of the setup for Outdoor Reset,
see Section 8C.5.
AdjustableHighLimit-
The absolute high limit setting for the water outlet
temperature for this unit is set at the factory to 195°F
(90.5°C). If you wish, you can also set a second or
“adjustable” limit setting that is lower.
Use the Up- and Down-Buttons to select the function, use
Up- and Down- to select the new value, then press the
round OK button.
AdjustableStackLimit-
The absolute high limit setting for the stack for this unit is
set at the factory to 195°F (90.5°C). If necessary, you can
set the unit to use a second or “adjustable” limit setting that
is lower.
Use the Up- and Down-Buttons to select the function, use
Up- and Down- to select the new value, then press the
round OK button.
8.7 24VACTransformer
 withIntegralCircuitBreaker
24Vac is supplied by a transformer mounted underneath the
control panel. All 24Vac power is supplied through a circuit
breaker that is part of the transformer. The transformer is then
connected to terminal blocks 3 and 4 (TB3 and TB4).
See Figure 31.
8.8  HydronicHeatingDemand
When using the NeoTherm for hydronic heating, a call for
heat must be supplied to the “T-T or Interlock” terminal. Once
the call is supplied, the control starts the Boiler and System
pumps, and begins the ignition process. The ignition process
consists of a prepurge, trial for ignition, and run period. The
prepurge period starts on a call for heat once the fan RPM
reaches a preset level. The trial for ignition period follows
once the start-up RPM of the fan has been reached. The trial
for ignition period lasts four seconds, During this period the
direct spark ignition system and gas valve are energized.
At the end of the trial for ignition period, the ame signal is
compared with the preset ame threshold value. If the ame
signal is higher than the ame threshold, the NeoTherm enters
Run. If the ame signal is below the threshold, the NeoTherm
returns to prepurge and starts the ignition process over. When
operating in Run, the NeoTherm monitors the ame signal,
call for heat input, safety switches, and water temperatures
and modulates as needed between 100% and 20% of rate to
satisfy the call for heat.
Connect the call for heat to terminal block 7 (TB7), See
Figure 31, connections labeled “T-T or interlock” in the
control panel.
The CH Setpoint can be set from the Quick Start menu.
How to get there: From the “Home” screen, press “I” to
go to “Info/ Install.” Choose “Quick Start,” then go to
“CH Setpoint.”
8.9  Anti-Short-Cycle(ASC)
The anti short cycle function helps to prevent short-cycling
when the call for heat switches on and off quickly.
To reach the anti-short-cycle function, select Info/ Advanced
Setup/ System Cong./ System Cong.
How to get there: From the “Home” screen, press “I”
to go to “Info/ Install.” Choose “Advanced Setup,” then
“System Conguration,” then “System Conguration”
again.
8.10 OutdoorAirTemperatureSensor
The outdoor air temperature sensor is used with the Outdoor
Reset and Warm Weather Shutdown functions.
CongurationandSetup