Modulex Light Commercial Series
CHAPTER 4: Installation Instructions
OMM-0158_A
• 6/28/2022 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST Page
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W A R N I N G !
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The gas connection must be installed by a registered engineer who must comply with
regulations in force and/or indicated by the local gas supplier. Incorrect installation can cause
injury or death to persons or animals, or damage to property. The manufacturer shall not be
held liable for any injury and/or damage due to inappropriate installation.
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Do not use the boiler for another type of gas than indicated on the identification plate of the
boiler. This will cause improper functioning and can damage the boiler.
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Always check the gas pipe system by means of a soap bubble test using a leak-search spray.
4.10 Natural Gas Connections
Contact your local gas supplier for natural gas pipe sizes and meter types.
4.10.1.1 Natural Gas Piping Connections
The boiler gas pipe is equipped with external 2
” M-NPT thread, 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.
4.10.1.2 Natural Gas Supply Pressure Requirements
The nominal inlet working gas pressure at the boiler should be
7” W.C.
(18 mbar) for Natural Gas
(Gas A). Maximum pressure with no flow (lockup) or with the boiler running is 10.5 inches W.C.
Minimum pressure with the gas flowing (verify during boiler startup) is 4.0 inches W.C.
4.11 Propane Gas Connections
4.11.1.1 Propane Gas Piping Sizes
Contact your gas supplier for Propane gas pipe sizes, tanks, and lockup gas pressure regulator.
4.11.1.2 Propane Gas Piping Connections
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Use a gas shut off valve compatible with propane gases.
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A sediment trap must be installed upstream of the gas controls.
The boiler pipe is provided with an external 2
” MNPT thread, 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.
The nominal inlet working gas pressure measured at the boiler should be 11” W.C. (27 mbar) for
Propane gas (Gas E).
A gas control valve must be installed adjacent to the boiler for isolation purposes.
4.11.1.3 Propane Gas Supply Pressure Requirements
Pressures required at gas valve inlet pressure port:
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Nominal gas pressure
– 11 inches W.C.
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Maximum gas pressure
– 13 inches W.C. with no flow (lockup) or with boiler running.
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Minimum gas pressure
– 8 inches W.C. with gas flowing (verify during boiler startup).
NOTE:
Install high gas pressure regulator at least 6 to 10 feet upstream of the boiler.
