LAARS LLS-1 - Instruction Manual - Manual (Page 4)

Page 4
LAARS HEATING SYSTEMS
• Main Gas Flame Status (if main burner flame
sensor is present)
• Pump / Circulator Status for Boiler and DHW
Pumps
• Fan Status
• Boiler Staging Status
• “Service Required” Indicators
SECTION 2.
Operation
2.1 Sequence of Operation
1.The main power switch is “ON”.
2.Space heating or domestic hot water “call for
heat” signal is initiated.
3.The status of the water temperature at the boiler
inlet is verified.
4.The status of the water temperature at the boiler
outlet is verified.
5.Auxiliary terminals are checked to make sure the
circuit is closed.
6.Boiler pump is energized (if controlled by the
LLS).
7.Vent damper is opened (if installed)
8.Vent damper proving switch is verified.
9.Venting fans are energized (if installed).
10.Controller verifies that power venter proving
switch has been made.
11.Controller verifies that the high gas pressure
switch has not tripped if unit is equipped with
switch.
12.Proper minimum gas pressure is verified if the
unit has low gas pressure switch.
13.If used on the unit, rollout switch, blocked vent
switch and fusible links are checked.
14.Differential pressure switches to verify proper
air flow through units are checked (if the unit
has such devices).
15.Flow switch is checked.
16.Adequate water level is verified through Laars
Low water cutoff (if equipped).
17.Controller performs a pre-flame sense check.
18.Ignition system is energized.
19.Controller performs a post flame sense check.
20.The main gas valve assembly is activated as
prescribed.
21.The main burner is ignited.
22.Call for heat is satisfied.
23.Main gas valve assembly is deactivated.
24.The pump is allowed to operate for a preset time,
after which is stops (if pump delay is activated).
25.Venting fan is allowed to post purge, after which
is stops (if programmed).
26.Vent damper stays open if post purge is
activated, after which time it closes.
SECTION 3.
Field Installed Connections
Connections that are made to the LLS controller
are described in this section. Sensors, field-supplied
switches, power venters, aquastats, etc. can be
connected directly to the LLS control. This section
describes the method of connection, as well as any
important information regarding connections (see
Figure 1). Many connections will require
programming/setup of the controller.
The LLS-1 has several operating parameters that
can be changed to ensure that the boiler operation best
meets the needs for your application.
Laars controls boiler water temperature at
inlet.
See Sections 5 and 6 for specifics about
programming options.
Field Interlock - T1
The field interlock connection is commonly
referred to as a T-T connection. This is for tank
aquastats and heating thermostats / end switches. The
boiler will not fire unless this connection is made.
WARNING
The Field Interlock connection is NOT for safety
switches that are used to prevent the boiler from
firing. For field-supplied safety switches, connect
directly through the boiler wiring or through the
auxillary switch connection on the LLS (J32). When
components are wired through the Field Interlock,
voltage to the main gas valves can be energized by
the DHW (domestic hot water) sensor, if used.
Contact the factory if you have any questions about
how to connect safety switches to the boiler or the
LLS.
Important Note About Tank Aquastats:
Standard tank aquastats must be connected to the
Field Interlock (T1), not the DHW Tank Temp (T3).
The aquastat will call for heat when the tank
temperature drops, as in a standard water heater setup.
DHW Tank Temp connection is for the Laars DHW
Sensor only. Do not enable or program parameters for
domestic water on the LLS when using a standard
tank aquastat, or the controller will “look for” the
Laars DHW Sensor.
Outside Air Temp - T2
Laars’ OAT (outside air temperature) Sensor is
connected here when outdoor reset is used in a heating
system. To ensure proper operation, only the Laars
OAT sensor should be used with the LLS.
OUT OF
PRODUCTION