Instruction manual

Atmospheric Gas Page 11
SECTION IV: INSTALLATION (cont.)
GAS CONNECTIONS
CAUTION
Do not use this water heater with any gas other than the type listed on the rating label.
Check the rating label on the front of the water heater and make sure the gas to be used
matches the gas stated on the rating label. Consult your local gas company or Bock Water
Heaters with any questions.
A manual valve, union, and a sediment trap should all be provided in front of the gas
thermostat. All gas piping must conform to local codes and/or the National Fuel Gas Code,
ANSI 223.1/NFPA 54 (latest edition).
Supply piping should be sized according to the charts found in the National Fuel Gas Code
for natural gas applications.
Note: When sizing the gas piping to the heater, make sure that the pressure at the valve is
sufficient when all other appliances are operating. Undersized gas piping will reduce water
heater performance and life as well as result in nuisance lockouts. Also verify that the gas
service and meter are sized properly for the load.
Gas piping should be carried oversize, i.e.:
3
⁄4 inch or 1 inch or larger for
1
⁄2 inch valve to
within 2 feet of the valve itself. This sustains pressure at the valve during start-up to prevent
flashbacks caused by momentary pressure loss. For natural gas, 5" W.C. pressure must be
maintained upstream of the gas valve during operation. For LP gas, a minimum of 11" W.C.
must be maintained upstream of the gas valve. A
1
⁄8 inch NPT pipe connection should be
installed upstream of the manual shut-off valve to check incoming gas pressure.
During pressure testing of the gas supply piping, close the manual gas shut-off valve to the
water heater. Test pressure shall not exceed
1
⁄2 PSIG (14" W.C). The gas valve is only rated for
1
⁄2 PSIG. To test at pressure greater than
1
⁄2 PSIG, close the manual shut-off valve and
disconnect the gas operating valve.
Turn on gas and inspect piping for leaks by “painting” each joint with soap and checking for
bubbles. Do not use open flame. The pipe thread compound that is used on gas piping must be
of the type resistant to propane gas. Do not use teflon tape on gas piping. Note: For high
altitude applications (above 2000 feet) contact Bock Water Heaters.
DRAFT HOOD AND VENTING
This water heater must be installed with the factory supplied draft hood. See Figure 3 for
placement. Vent connectors must be attached to the draft hood to connect the water heater to
the gas vent or chimney. The vent connector must be the same diameter as the outlet of the
draft hood. Never use a smaller diameter vent connector. Horizontal vent connectors must be
pitched upward to the chimney at least 1/4” per foot of length. Vent connector joints should
be securely fastened with sheet metal screws. For further specifications, see the National Fuel
Gas Code (NFPA 54).
DANGER
Substitution, elimination or relocation of the draft hood will result in unsafe operation
and void the warranty of your water heater. Improper venting or misuse of the draft
hood can result in unsafe operation causing bodily injury, explosion, fire or death. To
avoid the risk of fire, explosion, or asphyxiation from carbon monoxide, NEVER operate
this water heater unless it is properly vented and has an adequate air supply.
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