4
Midco
International
Inc.
8471 50
MADE
in the
USA
Part I - Installation
CAUTION: The available gas pressure should be within the limits shown in Table 1 -
SPECIFICATIONS section. Excessive pressure may damage electric valves, regulators
and manual valves. If the supply pressure exceeds the 14.0″ W.C. maximum, a suitable
high pressure regulator must be installed between the Main Manual Shut-Off Valve and
burner combination valve.
-
The burner gas supply piping should branch off from the main line as close to the gas meter as
possible. Do not connect to the bottom of a horizontal section. Use new black pipe and malleable
fi ttings free of cutting and threading burrs or defects.
-
Piping must also comply with your local codes.
-
To obtain the maximum fi ring rate of the burner, the gas supply piping must be sized to provide a
minimum pressure of 7.0″ W.C. (Natural) for 400 MBH to the inlet of the combination redundant valve
when the burner and all other gas utilization equipment are on refer to Table # 3 for 350 MBH and 250
MBH gas pressure requirements. The main regulator, if equipped, should be mounted upright and in
a horizontal run of pipe, refer to regulator manufacturer’s installation instructions.
CAUTION: Because it is diffi
cult to accurately control pressure during supply pipe leak
testing, it is recommended that all low pressure 1/2 PSIG (14.0″ W.C. max.) components
be disconnected during testing. Exposing low pressure regulators and valves, including
manual valves, to pressures over 1/2 PSIG (14.0″ W.C.) will cause damage and void all
warranties.
III Piping
BELIMO
BELIMO
MAXIMUM INLET
PRESSURE = 1/2 PSIG
COMBINATION
GAS VALVE
MANIFOLD GAS
PRESSURE TAP
AIR PRESSURE
SWITCH
(LOCATED INSIDE)
BLOWER MOTOR
DSI ELECTRONIC
CONTROL
COMBUSTION
DAMPER
ACUATOR
GAS VALVE ACTUATOR
WITH SPRING RETURN
LOW FIRE
BYPASS
LINE
LOW FIRE
ORIFICE
Figure 2 -
Typical Piping Diagram
DANGER: Explosion hazard.
Do not use oxygen for pressure testing.
An explosion could occur during initial start up.
-
If the burner piping must be rearranged because of space limitation, be sure to carry out the
general arrangement shown in Figure 2. Install the combination valve in any position except up-side
down.
-
When the burner is installed in the vestibule of jacketed equipment, it is recommended that the
Automatic Safety Shut-Off Valve be left adjacent to the burner within the vestibule and the Main
Manual Shut-Off Valve be installed outside.
