John Wood Takagi - 240H-340H-540H - Manual (Page 20)

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GAS SUPPLY AND GAS PIPE SIZING
-General-
• The minimum and maximum inlet gas pressures are:
• Inlet gas pressure except the ranges in the table above will adversely affect performance. 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.
-Gas connections-
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 3.5 kPa
(1/2 psi).
• 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 3.5 kPa (1/2 psi).
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
the water heater using CSA B149.1 or local codes. Otherwise, flow capabilities and
output temperatures will be limited.
NOTICE
Gas type Inlet gas pressure
Natural Gas Min. 1.24 kPa (5.0” W.C.) – Max. 2.61 kPa (10.5” W.C.)
Propane Min. 1.99 kPa (8.0” W.C.) – Max. 3.48 kPa (14.0” W.C.)
• 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.
• Conversion of this unit from natural gas to propane or vise 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.
CAUTION
Installation
Installation Manual