Natural Gas Connections; Natural Gas Piping Sizes; Natural Gas Piping Connections; Natural Gas Supply Pressure Requirements - Watts AERCO EXT Installation, Operation & Maintenance Manual

Modulex EXT Commercial Series
CHAPTER 4: Installation Instructions

4.9.1 Natural Gas Connections

Natural Gas Piping Sizes

Contact your local gas supplier for natural gas pipe sizes and meter types.

Natural Gas Piping Connections

The boiler gas pipe is equipped with external 3'' ASME B16.5 flange, onto which the tail piece
of the gas shut off valve can be connected. Use appropriate sealing.
The connection to the boiler must include a suitable method of disconnection and a gas control
valve must be installed adjacent to the boiler for isolation purposes.

Natural Gas Supply Pressure Requirements

The nominal inlet working gas pressure measured at the boiler should be 7" W.C. (18 mbar)
for natural gas. Maximum pressure with no flow (lockup) or with the boiler running is 10.5
inches W.C. Minimum pressure with gas flowing (verify during boiler startup) is 4.0 inches W.C.

4.9.2 Propane Gas Connections

Propane Gas Piping Sizes

Contact your local gas supplier for Propane gas pipe sizes, tanks, and 100% lockup gas
pressure regulator.

Propane Gas Piping Connections

The boiler pipe is provided with external 3'' ASME B16.5 flange, onto which the tail piece of
the gas shut off valve can be screwed. Use appropriate sealing.
The connection to the boiler must include a suitable method of disconnection. Use a gas shut
off valve compatible with propane gases. A sediment trap must be provided upstream of the
gas controls.

Propane Gas Supply Pressure Requirements

Pressures required at gas valve inlet pressure port:
•
Nominal gas pressure is 11 inches W.C.
•
Maximum gas pressure is 13 inches W.C. with no flow (lockup) or with boiler running.
•
Minimum gas pressure is 8 inches W.C. with gas flowing (verify during boiler startup).
NOTE: Ensure the high gas pressure regulator is installed at least 6-10 feet upstream of the boiler.

4.10 Flow And Return Pipe Connections

The cold and hot water flow and return circuits must be connected to the boiler via the
respective 4" M and R connections as indicated in Table 2-1.
When determining the size of the cold/hot water circuit pipes, bear in mind the pressure losses
induced by any of the system's components and by the configuration of the system.
When planning the routing of the cold/hot water piping, take the necessary precautions to avoid
air traps and pockets and to facilitate the continuous purging of the system.
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