MASCOT MSTWW, Installation And Operation Instructions Manual

Page: 26 / 68

LAARS Heating Systems
Page 24
The gas connection fitting on the unit is 3/4˝ female
NPT.
The supply line must be sized for the maximum
output 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
recommended that an approved gas union fitting
Gas line close position Gas line open position
be installed in the supply line between the shut-off
valve and the 3/4˝ female NPT connection on the
Water Heater.
1) Install an approved gas line 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
minimum standards and does not exceed the
maximum standards for the water heater.
3) Leak test the gas line 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.