Gas Supply And Gas Pipe Sizing; General; Gas Connections - Takagi 540P Indoor Installation Manual And Owner's Manual

GAS SUPPLY AND GAS PIPE SIZING

• Check that the type of gas matches the rating plate first.
• Ensure that any and all gas regulators used are operating properly and
providing gas pressures within the specified range shown below. Excess gas
inlet pressure may cause serious accidents.
WARNING
• Conversion of this unit from natural gas to propane or vice versa will void
all warranty. Contact your local distributor to get the correct unit for your
gas type. The manufacturer is not liable for any property and/or personal
damage resulting from gas conversions.
• Failure to observe these warnings could result in severe personal injury, carbon
monoxide poisoning, or death.
• The minimum and maximum inlet gas pressures are:
Gas type
Natural Gas
Propane
• Inlet gas pressures that fall outside the range of values listed above may adversely affect the
performance of the water heater. These pressures are measured when the water heater is in full
operation.
• Inlet gas pressure must not exceed the above maximum values; gas pressure above the specified range
will cause dangerous operating conditions and damage to the unit.
• Until testing of the main gas line supply pressure is completed, ensure the gas line to the water heater
is disconnected to avoid any damage to the water heater.
• If the gas supply pressure to the heater is greater than the specified maximum, a field-supplied
regulator is required. The regulator must lower the gas pressure within the approved range.
• Install the gas regulator according to the manufacturer's instructions.
• The regulator must be sized for the water heater input and provide the specified pressures that are
listed on the rating plate.
• In the absence of minimum install distance, it is recommended that there is at least 3 ft (1 m) of piping
between the regulator outlet and the water heater's inlet gas connection.
1. Install a manual gas shutoff valve between the water heater and the gas supply line.
2. When the gas connections are completed, it is necessary to perform a gas leak test either by applying
soapy water to all gas fittings and observing for bubbles or by using a gas leak detection device.
• The water heater and its individual shutoff valve must be disconnected from the gas supply
piping system during any pressure testing of that system at test pressures in excess of 1/2 psi
(3.5 kPa).
• The water heater must be isolated from the gas supply piping system by closing its individual
manual shutoff valve during any pressure testing of the gas supply piping system at test
pressures equal to or less than 1/2 psi (3.5 kPa).
3. Always purge the gas line of any debris and/or water before connecting to the gas inlet.
Size the gas pipe appropriately to supply the necessary volume of gas required for
NOTICE
the water heater using ANSI Z223.1/NFPA 54 in the USA or B149.1 in Canada or
local codes. Otherwise, flow capabilities and output temperatures will be limited.

-General-

Inlet gas pressure
Min 4.0" W.C. (1.00 kPa) – Max. 10.5" W.C. (2.61 kPa)
Min 8.0" W.C. (1.99 kPa) – Max. 14.0" W.C. (3.48 kPa)

-Gas connections-

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