Part 8: gas piping, Warning – Munchkin Gas-Fired Hot Water Circulating Heater User Manual

Page 46

GAS-FIRED HEATER

Installation Manual

A. GAS CONNECTION

The gas sup-
ply shall have
a m a x i m u m
inlet pressure
of less than 14"
water column
(350 mm), ½
pound pres-
sure (3.5 kPa),
a n d a m i n i -
mum of 3.5"
water column.
The entire pip-
ing system, gas meter and regulator must be
sized properly to prevent pressure drop greater
than 0.5" as stated in the National Fuel Gas
Code. This information is listed on the rating
plate. It is very important that you are connect-
ed to the type of gas as noted on the rating
plate. "LP" for liquefied petroleum, propane gas
or, "Nat" natural or city gas. 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. The nipple
provided is ½" with a factory installed. Do not
remove this ¾" x ½" bell reducer! It is mandato-
ry that this fitting is used for connection to a field
fabricated 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 Munchkin Contender is no smaller than
¾". Once all the inspections have been per-
formed, the piping must be leak tested. If the
leak test requirement is a higher test pressure
than the maximum inlet pressure, you must iso-
late the Munchkin Contender from the gas line.
In order to do this, you must shut the gas off
using factory and field-installed gas cocks. This
will prevent high pressure. Failure to do so may
damage the gas valve. In the event the gas valve
is exposed to a pressure greater than ½ PSI, 14"
water column, the gas valve must be replaced.
Never use an open flame (match, lighter, etc.) to
check gas connections.

PART 8: GAS PIPING

B. GAS PIPING

1. Run the gas supply line in accordance with all

applicable codes.

2. Locate and install manual shutoff valves in

a c c o r d a n c e w i t h s t a t e a n d l o c a l
requirements.

C. GAS TABLE

Refer to Table 8.2 to size the supply piping to
minimize pressure drop between meter or
regulator and unit.

Maximum Capacity of Pipe in Cubic Feet of Gas
per Hour for Gas Pressures of 0.5 psi or Less and
a Pressure Drop of 0.3 Inch water Column

(TABLE 8-2) (Based on a 0.60 Specific Gravity Gas)

It is recommended that a soapy solution be used
to detect leaks. Bubbles will appear on the pipe to
indicate a leak is present. The gas piping must be
sized for the proper flow and length of pipe, to
avoid pressure drop. Both the gas meter and the
gas regulator must be properly sized for the total
gas load. If you experience a pressure drop
greater than 1" WC, the meter, regulator or gas
line is undersized or in need of service. You can
attach a manometer to the incoming gas drip leg,
by removing the cap and installing the
manometer. The gas pressure must remain
between 3.5" and 14" during stand-by (static)
mode and while in operating (dynamic) mode. If
an in-line regulator is used, it must be a
minimum of 10 feet from the Munchkin

WARNING

Failure to follow all precautions could result in
fire, explosion or death!

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