Detroit Radiant Products Company DES3 Series - Manual (Page 31)

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3.0 Installation • Gas Supply
Chart 3.8 Manifold Pressure
The installation must conform with local building codes or, in the absence of such codes, the National Fuel
Code (NFPA 54) and in conjunction with ANSI Z21.24/CSA 6.10 “Connectors for Gas Appliances”.
Important! The heating system will expand and contract during operation. Allowances for expansion must
be made between the connection to the heater and the gas supply. Excessive bending, kinks, twists or
vibration must be avoided. A flexible gas connection of approved type is required. Flexible stainless steel
gas connectors installed in one plane, and without sharp bends, kinks or twists is recommended.
The gas pipe and connection must be supported independently. Do not install gas supply line in a manner
that bears the weight of the heater. Connect the main gas supply line with an approved flexible connector
(Figure 3.30) or, if national or local codes require rigid piping, a swing joint. See the safety messages at
the beginning of this section.
The gas outlet must be in the same room as the appliance and accessible. It may not be concealed within
or run through any wall, floor or partition. When installing the heater in a corrosive environment (or near
corrosive substances), use a gas connector suitable for the environment. Do not use the gas piping
system to electrically ground the heater.
Install a sediment trap / drip leg if condensation may occur at any point of the gas supply line. This
will decrease the possibility of loose scale or dirt in the supply line entering the heater’s control system
and causing a malfunction. NOTE: High pressure gas above 14 Inches W.C. (water column pressure)
requires a high pressure regulator and ball valve (field supplied).
WARNING
!
Failure to install, operate or service this appliance in the approved manner may result in
property damage, injury or death. Only trained, qualified gas installation and service
personnel may install or service this equipment.
To connect the gas:
• Test and confirm that inlet pressures are correct. Refer to the heater rating plate for gas type and
the required minimum and maximum pressures (see Chart 3.8). The gas supply pipe must be of
sufficient size to provide the required capacity and inlet pressure to the heater (if necessary,
consult the local gas company). Do not exceed the maximum allowed pressures for the heater,
the space or the gas piping system.
Pressure Equivalents: 1 inch W.C. equals .058 oz/sq. in. equals 2.49 mbar.
NOTE: Check manifold pressure at the tap on the gas valve. Small variations in manifold pressure (actual
vs. published) may exist due to changing atmospheric conditions. Readings will be above atmospheric
pressure.
Type of Gas
Required Manifold
Pressure
Minimum
Inlet Pressure
Maximum
Inlet Pressure
Natural 3.5 Inches W.C. 5.0 Inches W.C. 14.0 Inches W.C.
Liquefied Petroleum 10.0 Inches W.C. 11.0 Inches W.C. 14.0 Inches W.C.
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