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P/N 42-9470 11/07 Copyright 2007 Mestek, Inc.
Cast iron condensing boiler
Cast iron condensing boiler
— Installation and operation manual
Gas piping
Figure 14
Connecting gas supply line
Failure to adhere to the following
could result in severe personal in-
jury, death or substantial property
damage.
Verify the gas type
Check the boiler rating plate to make sure that the boiler
is for the type of gas that will be used. If it is not, do not
connect the boiler to the gas supply.
Support the gas line
Support the gas line with hangers. DO NOT allow gas
train weight to rest on or cause bending of the boiler gas
connection fi tt ing.
Protect the gas connection fi tting
Use a 15/16 – inch open-end wrench to hold the boiler
gas connection fi tt ing when tightening gas connection
piping to the boiler.
Never leak test with fl ame
Never use an open fl ame to test for gas leaks. Always use
an approved leak detection method.
Protect the boiler gas valve from
excessive pressure
When pressure testing system gas piping, disconnect
the gas piping from the boiler or isolate the boiler with
the manual shut-off valve if test pressure will be higher
than ½ psig (3.5 kPa).
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Piping from gas supply
2
Manual gas valve with test port
(use tee-handle valve for
Massachusett s installations)
3
Piping must be clean and burr-free
black iron pipe
4
Ground-joint
union
5
Drip leg with cap
6
Gas cock pressure test port
Check the gas type
Th e
200i
comes from the factory ready to be piped to the gas
supply. If for any reason the boiler is not for the type of gas avail-
able at the installation site, call your Mestek representative to
resolve the problem. (See WARNING below.)
Gas supply components
Figure 14 depicts the proper way to connect the boiler to the gas
supply piping. Th e gas connection at the boiler is ½” NPT.
Item 1 — Install the gas line piping from the gas meter or branch
in accordance with all applicable codes. See the next page for
suggested sizing, or refer to the National Fuel Gas Code or Ca-
nadian Gas Code for recommendations.
Item 2 — Th e manual shut-off valve must be installed in the
supply piping. Install 5 feet above the fl oor where required by
applicable codes.
Item 3 — For all gas supply piping, use only clean, burr-free black iron pipe, supported
independently from the boiler gas connection.
Item 4 — Install a ground-joint union in the gas line for ease of installation and servicing.
Item 5 — Provide a sediment trap at the bott om of the vertical section of the gas supply
pipe upstream of the gas controls.
Item 6 — Th e gas cock must be equipped with a pressure test port. Th is test port is
used to measure the gas supply pressure at the boiler.
Th e gas line components in Figure 14 are not supplied with the boiler. Th ey must be
supplied by the boiler installer.
Always use a wrench on the gas grain components when making gas
connections. Never over-tighten the piping components or a failure
could result, causing possible severe personal injury, death or substantial
property damage.
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