Heat Transfer MODCON VWH 300 HL, Installation & Maintenance

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PART 7: GAS PIPING
GAS-FIRED HOT WATER SUPPLY BOILER
Boiler Manual
39
A. GAS CONNECTION
The gas supply shall have a maximum inlet
pressure of less than 14" w.c. (3.5 kPa), and a
minimum of 3.5" w.c. (.87 kPa). The entire piping
system, gas meter and regulator must be sized
properly to prevent pressure drop greater than
0.5" (.12 kPa) as stated in the National Fuel Gas
Code. This information is listed on the rating
label.
The gas connection on the Mod Con is 1-1/4” for
the Mod Con 300, 1-1/2” for the Mod Con 500
and 2” for the Mod Con 850. It is mandatory that
this fitting is used for connection to a field fabri-
cated drip leg as shown in the illustration above
per the National Fuel Gas Code. You must
ensure that the entire gas line to the connection
at the Mod Con is no smaller than the unit sup-
plied connection. Once all the inspections have
been performed, the piping must be leak tested.
If the leak test requirement is a higher test pres-
sure than the maximum inlet pressure, you must
isolate the Mod Con from the gas line. In order
to do this, you must shut the gas off using fac-
tory and field-installed gas cocks. This will pre-
vent high pressure. Failure to do so may dam-
age the gas valve. In the event the gas valve is
exposed to a pressure greater than ½ PSI, 14"
w.c. (3.5 kPa), the gas valve must be replaced.
Never use an open flame (match, lighter, etc.) to
check gas connections.
B. GAS PIPING
1. Run the gas supply line in accordance with all
applicable codes.
2. Locate and install manual shutoff valves in ac-
cordance with state and local requirements.
3. In Canada, the Manual Shutoff must be
identified by the installing contractor.
4. It is important to support gas piping as the
unit is not designed to structurally support
large amount of weight.
5. Purge all gas lines thoroughly to avoid start
up issues with air in the lines.
6. Sealing compound must be approved for gas
connection. Care must be taken when
applying compound to prevent blockage or
obstruction of gas flow which my effect the
operation of the unit.
n
WARNING
It is very important that you are connected to
the type of gas as noted on the rating plate.
“LP” for liquefied petroleum, propane gas or,
“Nat” natural or city gas. You must not do a gas
conversion on this boiler. All gas connections
must be approved by the local gas supplier, or
utility in addition to the governing authority,
prior to turning the gas supply on.
n
WARNING
Never use an open flame (Match or Lighter) to
check for Gas leaks. Use A soapy solution to
test gas connection for leaks. Failure to use
soapy solution test or check gas connection for
leaks can cause substantial property damage,
severe personal injury or death .
NOTICE
CSA or UL listed Flexible gas connections can
be used when installing The Mod Con Boiler.
Flexible gas connections have different
capacities and must be sized correctly for the
connected boiler firing rates. Consult with the
flex line supplier to assure the line size is
adequately sized for the job. Follow local codes
for proper installation and service requirements.
n
WARNING
Failure to follow all precautions in this section
could result in fire, explosion or death!