8
Midco International Inc.
8471 91
MADE
in the
USA
Part 1 - Installation
The Midco LNB is provided with all required gas train assembly components. Refer to piping diagram
Figure 4A and 4B for a typical installation. Modifi cations can be made to the piping layout if required.
The Ratio Regulator Zero Governor valve position CAN NOT be changed as this is critical in burner
performance. The orifi ce located downstream from the Ratio Regulator Zero Governor valve must not
be modifi ed. When the gas train assembly installation is complete turn on gas to the unit and check
for any gas leaks. Repair any leaks that are found at this time. The minimum required gas pressure at
the inlet of the valve train is 5″ W.C. and maximum gas pressure is 14″ W.C.. The outlet gas pressure
should be set at 6″ W.C. when burner is at high fi re. Turn off main manual gas valve before starting the
unit. Consult the Midco technical support team if there are any piping questions. See Burner Startup,
section V, for operating instructions.
III Piping
Figure 4A - Piping - LNB 500 - Standard
PRE ASSEM BLED SECTION
EBM RG175/2000-3633 BLOWER
8435-30
BLOWER INLET KIT
8416-22
DUNGS 3/4" RATIO
GOVERNOR
8416-21
1" UNION
8493-06
3/4" QUICK
ACTUATED
BALL VALVE
8404-37
3/4" x 2" NIPPLE
8488-02
3/4" x 3" NIPPLE
WITH ORIFICE
5246-85
3/4" x 2"
NIPPLE
8488-02
3/4" SOLENOID
VALVE 24 V
8402-35
3/4" x 2"
NIPPLE
8488-02
3/4" T HAND
BALL VALVE
8404-30
3/4" REGULATOR
RV53
8416-01
3/4" SOLENOID
VALVE 24 V
8402-35
3/4" x 2" NIPPLE WITH
PRESSURE TAP
5243-29
3/4" x 3"
NIPPLE
8488-04
FUEL GAS
3/4" x 6"
NIPPLE
8488-15
3/4" ELBOW
8495-22
3/4"
ELBOW
8495-22
3/4" x 3"
NIPPLE
8488-04
1/8" PIPE
PLUG
8496-00
BALANCE SHIPPED LOOSE
1" X 3/4" HEX
BUSHING
8492-52
MANOMETER
MAIN MANUAL GAS
YELLOW
AND FLOW ARROW
REGULATOR ZERO
Chart 1 - Gas Pressure - LNB 1000
1000
950
900
850
800
750
700
650
600
550
500
450
400
350
300
250
200
150
100
50
0
0.00 0.10
2.20
2.10
2.00
1.90
1.80
1.70
1.60
1.50
1.30
1.20
1.10
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
1.40
FIRING RA
TE, MB
TU/HR
LNB 1000 FIRING RATE vs PRESSURE DIFFERENCE ACROSS
TWO SOLENOID VALVES
PRESSURE DIFFERENCE ACROSS TWO SOLENOID VALVES, “W.C.
