Laars Pennant PNCH Installation And Operation Instructions Manual - page 42
LAARS Heating Systems
Page 42
Figure 28. Temperature Control Interstage Differential.
6.4 Advanced Topics
For most installations, Section 6.3 provides all
the information required to set up the Pennant boiler,
and this section should be skipped. Continue setup in
Section 6.5.
This section provides definitions of the pro-
gramming parameters, advanced programming topics,
and other information that may be of interest.
Advanced programming mode allows the installer
to set the temperature control for proportional staging.
In advanced programming mode, the interstage
differential, interstage delay, interstage on and off
delay, and minimum time on and off are all set
manually.
NOTE: Advanced programming mode is not required in
most applications, and is intended for advanced
installers only.
To enter advanced programming mode, remove
the bezel on the temperature control by pulling out at
the bottom. Remove the small phillips head screw to
access the dip switch. The dip switch is mounted on a
circuit board. Locate the letter “A” on the circuit
board and slide the corresponding dip switch toward
the letter “A”. The default setting of this dip switch is
toward the
OFF
lettering on the circuit board.
6.4.1 Differential
Differential has an abbreviated name of DIFF.
An on/off heat source must be operated with a
differential in order to prevent short cycling. The
differential is divided around the boiler target
temperature (see Figure 28). The first stage contact
will close when the water temperature at the operating
sensor is one-half of the differential setting below the
target temperature. It will open when the water
temperature at the operating sensor is one-half of the
differential setting above the target temperature. The
remaining stages will operate sequentially, based on
the staging mode selected.
6.4.2 Staging Mode
The Pennant 500 and 750 control operates two
stages. The Pennant 1000 control operates three
stages. The Pennant control for models 1250–2000
operates four stages. The method of staging used by
the control is either P (proportional) or PID
(proportional & integral & derivative), and is selected
using the STGMODE
STGMODE
STGMODE
STGMODE
STGMODE item in the ADJUST
ADJUST
ADJUST
ADJUST
ADJUST menu.
Proportional (P
PPPP) – Proportional staging, also
known as step staging, is based on manually adjusted
settings which determine when the next stage is
required to turn on. These manual settings are based
on temperature and time. The interstage differential
sets the temperature drop at which the next stage turns
on. However, in order for a stage to fire, the interstage
delay on and minimum off times must first elapse.
Interstage Differential (STG DIFF
STG DIFF
STG DIFF
STG DIFF
STG DIFF) – The
interstage differential is the temperature drop at which
the next stage will turn on. Once a stage turns on, the
next stage cannot turn on until the temperature drops
the interstage differential below the temperature at
which the previous stage turned on. The interstage
differential is adjustable through the STG DIFF
STG DIFF
STG DIFF
STG DIFF
STG DIFF setting
in the Adjust
Adjust
Adjust
Adjust
Adjust menu (see Figure 28).
Interstage Delay On (ON DLY
ON DLY
ON DLY
ON DLY
ON DLY) – The interstage
delay on is the amount of time that must elapse before
turning on the next stage. Once a stage turns on, the
next stage cannot turn on until the interstage delay on
time elapses. The interstage delay on is adjustable
through the ON DLY
ON DLY
ON DLY
ON DLY
ON DLY setting in the Adjust
Adjust
Adjust
Adjust
Adjust menu.
Interstage Delay Off (OFF DLY
OFF DLY
OFF DLY
OFF DLY
OFF DLY) – The interstage
delay off is the amount of time that must elapse before
turning off the next stage. Once a stage turns off, the
next stage cannot turn off until the interstage delay off
time elapses. The interstage delay off is adjustable
through the OFF DLY
OFF DLY
OFF DLY
OFF DLY
OFF DLY setting in the Adjust
Adjust
Adjust
Adjust
Adjust menu.
Minimum On Time (MIN ON
MIN ON
MIN ON
MIN ON
MIN ON) – The minimum on
time is the minimum amount time that a stage must be
on before it is allowed to turn off. Once a stage turns
on, it cannot turn off until a minimum on time elapses.
The minimum on time is adjustable through the MIN ON
MIN ON
MIN ON
MIN ON
MIN ON
setting in the Adjust
Adjust
Adjust
Adjust
Adjust menu.
Minimum Off Time (MIN OFF
MIN OFF
MIN OFF
MIN OFF
MIN OFF) – The minimum
off time is the minimum amount time that a stage must
be off before it is allowed to turn on. Once a stage
turns off, it cannot turn on until a minimum off time
elapses. The minimum off time is adjustable through
the MIN OFF
MIN OFF
MIN OFF
MIN OFF
MIN OFF setting in the Adjust
Adjust
Adjust
Adjust
Adjust menu.
Proportional & Integral & Derivative (PID
PID
PID
PID
PID) –
PID staging allows the control to determine when the
next stage is required to turn on. The control
automatically determines the settings that are manually
selected in proportional staging mode. After each
stage is turned on in the firing sequence, the control
waits a minimum amount of time before turning on the