Midco Unipower G-Series - Manual (Page 11)

11
fire input rate or the recommended minimum input as shown in Table 1, whichever is higher. If
further adjustments are required, screw in or back off the low fire adjustment screw
and adjust the air shutter until a satisfactory flame is achieved. Check combustion per paragraph
13, page 9, and mark the position of the low fire shutter setting with a pencil or scratch mark on
the blower housing.
3 . With burner switch off, remove jumper from modulating motor terminals "R-W" and reconnect
controller wires to terminals "B" and "W". Reconnect the air shutter connecting rod. Operating
linkage manually, adjust to index marker air shutter positions with high and low positions of the
input adjuster.
4 . Restart the burner and cycle it several times using the modulating control and the on-off control to
assure proper operation and correct linkage of the air shutter connecting rod. Conclude start-up
procedure per paragraph 15.
After the initial start-up procedure, the following steps can be followed for routine start-up and shut-
down on a seasonal or extended basis.
This table is provided as a guide to use the INPUT ADJUSTING METHOD to approximate final settings.
The valve train M U S T be tested for tightness and the pilot adjusted for proper operation before
proceeding. Refer to Section VIII Burner Box and Firing Head of the this manual.
1 . Install a Manometer (not a
pressure gauge) in the manifold
pressure tap.
2 . Close the Main Manual Gas
V a l v e .
3 . Close the Input Adjuster
(butterfly valve).
4 . Turn the burner on.
5 . Adjust the air shutter to the "Air
Only" pressure shown for the
desired MBH.
6 . Open the Main Manaual Gas
V a l v e .
7 . Slowly open the Input Adjuster
until the observed manifold
pressure equals the Gas On
pressure for the desired MBH.
8 . Take combustion readings and
confirm the input rate by
clocking the gas meter.
9 . Adjust the air shutter and/or the
Input Adjuster as needed.
1 0 . Repeat steps 8 and 9 until you
have the desired input rate with
clean combustion**.
1 1 . Refer to section VIII Burner Box
and Firing Head of this manual
for final Main Gas Regulator
adjustment procedures.
For capacities not shown:
P
2
= P
1
x
( M B H
2 M B H
1
)
2
*1 MBH=1000 BTU/HR.
ALL FIGURES ARE APPROXIMATE.
Actual figures will vary depending
upon application and ambient
conditions. Based on 0 pressure over
the fire at Standard Air and S p e c i f i c
G r a v i t i e s of .64 for NATURAL GAS,
and 1.52 for PROPANE GAS. It is the
responsibility of the installer to make
final adjustments to insure proper and
safe operating conditions, and to
comply with all codes and guidelines
that may apply at the installation site.
Contact the local Utility for any
requirements and recommendations
they may have. In the absence of any
local codes, guidelines or requirements,
refer to the National Fuel Gas Code,
Model
Capacity
MBH*
Air
Only Natural Propane
Manifold Pressures ("W.C.)
Gas On
G56
G57
G58
G69
1075
1000
900
800
700
600
500
300
1500
1300
1200
1000
900
700
600
300
1850
1700
1600
1500
1200
1000
800
500
2500
2200
2000
1800
1500
1200
1000
800
1.00
0.87
0.70
0.55
0.42
0.31
0.22
0.08
1.90
1.43
1.22
0.84
0.68
0.41
0.30
0.08
2.65
2.24
1.98
1.74
1.11
0.77
0.50
0.19
2.25
1.74
1.44
1.17
0.81
0.52
0.36
0.23 2.10
1.82
1.47
1.16
0.89
0.65
0.45
0.16
4.10
3.08
2.62
1.82
1.48
0.89
0.66
0.16
4.60
3.88
3.44
3.02
1.94
1.34
0.86
0.34
4.15
3.21
2.66
2.15
1.49
0.96
0.66
0.42 1.45
1.25
1.01
0.80
0.61
0.45
0.31
0.11
2.79
2.10
1.79
1.24
1.01
0.61
0.45
0.11
3.75
3.17
2.80
2.47
1.58
1.10
0.70
0.27
3.65
2.83
2.34
1.89
1.31
0.84
0.58
0.37
Table 4: Approximate G-Series Capacities at
Specified Manifold Pressures
Burner Start Up
1 .
Make sure line switch is off
2 . Set controller to call for heat
3 . Open firing door
4 . Open Main and Pilot Manual Valves
5 . Reset flame safeguard
6 . Turn on line switch
7 . Close firing door after main flame ignites
8 . Reset control to desired setting
Burner Shut down
1 .
Turn off main line switch
2 . Close Main Manual Valve
3 . Close pilot manual