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Modu-Fire
®
Gas-Fired Boiler Installation
15
the main burner shuts off (the green "Heat" indicator
will go out). The high-limit switch must be manu-
ally reset after testing. This same check should also
be made for the "Operating Temperature" control.
After completion of these tests, readjust thermostats
to desired operating temperature and set high-limit
temperature, typically 20º F above operating tem-
perature.
3.11.4 Test of Low Gas Pressure Switch
Gas Pressure Switch
The boiler is furnished with a low gas pressure
switch. The operation of this switch must be
checked by slowly closing the main gas cock while
the burner is operating. The switch should shut
down the main burner. When the gas pressure
switch opens, the "Gas Press." indicator will light.
Upon reopening the main gas cock, the "Gas Press."
indicator should remain on until the low gas pres-
sure switch is manually reset.
3.11.5 Test of High Gas Pressure Switch
The correct setting of the high gas pressure switch is
essential for proper operation of the boiler. This
switch is set by the factory at 4.0” w.c. and must not
be changed.
This switch must be checked by factory-trained per-
sonnel.
3.12
INITIAL ADJUSTMENTS
3.12.1A – Configuring the Local Controller
(Applies to models furnished with programmable
temperature control.)
Operating Modes:
Internal Setpoint
Night Setback (Alternate Setpoint)
Outdoor Air Reset
Analog Input Setpoint (See Section 3.12.1B.)
Analog Input Direct Drive (Multiple boiler
Controls)
Definitions:
SP1- Setpoint 1: ...................This is the primary
setpoint of the boiler.
SP2- Setpoint 2 : ...................An alternate setpoint.
Available through the
alternate setpoint con-
tact closure.
dSP- Differential Setpoint : ..An alternate setpoint
differential from SP1.
Available through the
alternate setpoint con-
tact closure.
tA- Air temperature: ............Measurement of out-
side air temperature.
SP.E- External Setpoint:.......Measurement of the
external setpoint.
HyS1:....................................Low temperature dif-
ferential.
HyS3:....................................High temperature dif-
ferential.
Internal Setpoint
The boiler water outlet temperature is controlled to
SP1 (setpoint 1) and the boiler modulates to main-
tain SP1 subject to the upper and lower temperature
differentials and the upper and lower setpoint limit.
Manual Reset