TriangleTube Marquis TWH180, Installation Manual

Page: 18 / 39

Gas Piping
15
• The gas connection fitting on the unit is 3/4˝ female
NPT.
• The supply line must be sized for the maximum out-
put of the water heater model being installed. If there
are additional gas appliances from the main supply
line, you must measure sizes of the supply line
according to the COMBINED total maximum BTUH
draw for the appliances as if they were all operating
at the same time.
• Measure the length of the gas supply line from the
gas meter to the Water Heater.
• Use the tables in this manual or refer to the gas line
manufacturers sizing information to determine the
correct supply pipe size.
• The gas shut-off valve in the gas supply line should
be installed close to the unit.
• To facilitate any future maintenance, it is also rec-
ommended that gas union be installed in the supply
line between the shut-off valve and the 3/4˝ female
NPT connection on the Water Heater.
1. Install gas pipe to gas line connection under the
Water Heater. Include manual shut off valve and
gas union connection, as shown.
2. Test gas pressure to make sure it meets the min-
imum standards and does not exceed the maxi-
mum standards for the water heater.
3. Leak test the gas pipe before placing the unit in
operation. Use approved leak detector liquid
solutions only to check for leaks.
• Do not operate the water heater until all connections
have been completed and the heat exchanger is
filled with water
Valve closed Valve open
Marquis Manual_61515_Water Heater 7/1/15 1:58 PM Page 18