Midco HMA-2 & HMA-2A Series - Manual (Page 10)

10
Midco International Inc.
8471 34
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Installation
Typical
Gas Train
Assembly
400,000 BTU/Hr
and Under
Flame Rod
Pilot
Spark Rod
Burner
Pilot Tube
Union
Modulating Valve
Manual Pilot Valve
Combination Gas Valve with
Main & Pilot Regulator
Main Manual
Gas Valve
*
A heater having an input over
400,000 BTU/Hr shall have
provisions for measuring gas
pressure between the valves,
except for heater incorporating
a single safety shut-off valve
with valve seal over travel
interlock. (ANSI Z83.4)
Flame Rod
Pilot
Spark Rod
Burner
Pilot Tube
Union
Manual
Firing Valve
Modulating
Valve
Pilot
Regulator
Pilot
Valve Manual Pilot
Valve
Main Manual
Gas Valve
Main
Regulator
Main
Operating
Valves
Safety Shut-off
Valve
Pilot Gas Pressure Tap
* A manifold pressure tap
needs to be provided
at the burner to check
manifold pressure
* Typical Gas
Train Assembly
400,000 BTU/Hr
and Above
Figure 5a - Gas Train Assemblies
Typical Gas Train Assembly
Figure 4 - Installation in a Duct
Elbow Duct Limits
Minimum Straight
Run 1-1/2 x "A"
Duct Height "A"
3 Ft. Minimum Minimum Straight
Run 2 x "B" 3 Ft. Minimum
Duct Width "B"
Air Flow Air Flow
Profile Plate Profile Plate
Push-Thru Systems
Continued