Goodman Mfg ANSI Z21.47CSA-2.3 用户手册

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12
G
AS
 P
IPING
 C
HECKS
T
O
 
PREVENT
 
PROPERTY
 
DAMAGE
 
OR
 
PERSONAL
 
INJURY
 
DUE
 
TO
 
FIRE
THE
 
FOLLOWING
 
INSTRUCTIONS
 
MUST
 
BE
 
PERFORMED
 
REGARDING
 
GAS
 
CONNECTIONS
 
AND
 
PRESSURE
 
TESTING
:
 •   T
HE
 
UNIT
 
AND
 
ITS
 
GAS
 
CONNECTIONS
 
MUST
 
BE
 
LEAK
 
TESTED
 
BEFORE
 
PLACING
 
IN
 
OPERATION
. B
ECAUSE
 
OF
 
THE
 
DANGER
 
OF
 
EXPLOSION
 
OR
 
FIRE
NEVER
 
USE
 
A
 
MATCH
 
OR
 
OPEN
 
FLAME
 
TO
 
TEST
 
FOR
 
LEAKS
. N
EVER
 
EXCEED
 
SPECIFIED
 
PRESSURES
 
FOR
 
TESTING
H
IGHER
 
PRESSURE
 
MAY
 
DAMAGE
 
GAS
 
VALVE
 
AND
 
CAUSE
 
OVERFIRING
 
WHICH
 
MAY
 
RESULT
 
IN
 
PREMATURE
 
HEAT
 
EXCHANGE
 
FAILURE
.
•    T
HIS
 
UNIT
 
AND
 
ITS
 
SHUT
OFF
 
VALVE
 
MUST
 
BE
 
DISCONNECTED
 
FROM
 
THE
 
GAS
 
SUPPLY
 
DURING
 
ANY
 
PRESSURE
 
TESTING
 
OF
 
THAT
 
SYSTEM
 
AT
 
TEST
 
PRESSURES
 
IN
 
EXCESS
 
OF
 1/2 PSIG (3.48 
K
P
A
).
•    T
HIS
 
UNIT
 
MUST
 
BE
 
ISOLATED
 
FROM
 
THE
 
GAS
 
SUPPLY
 
SYSTEM
 
BY
 
CLOSING
 
ITS
 
MANUAL
 
SHUT
OFF
 
VALVE
 
DURING
 
ANY
 
PRESSURE
 
TESTING
 
OF
 
THE
 
GAS
 
SUPPLY
 
PIPING
 
SYSTEM
 
AT
 
TEST
 
PRESSURES
 
EQUAL
 
TO
 
OR
 
LESS
 
THAN
 1/2 PSIG (3.48 
K
P
A
).
CAUTION
T
O
 
AVOID
 
PROPERTY
 
DAMAGE
 
OR
 
PERSONAL
 
INJURY
BE
 
SURE
 
THERE
 
IS
 
 
IN
 
THE
 
VICINITY
 
DURING
 
AIR
 
BLEEDING
.
NO
 
OPEN
 
FLAME
WARNING
There will be air in the gas supply line after testing for leaks
on a new installation. Therefore, the air must be bled from
the line by loosening the ground joint union until pure gas is
expelled. Tighten union and wait for five minutes until all gas
has been dissipated in the air. Be certain there is no open
flame in the vicinity during air bleeding procedure. The unit is
placed in operation by closing the main electrical disconnect
switch for the unit.
PROPANE GAS INSTALLATIONS
T
O
 
AVOID
 
PROPERTY
 
DAMAGE
PERSONAL
 
INJURY
 
OR
 
DEATH
 
DUE
 
TO
 
FIRE
 
OR
 
EXPLOSION
 
CAUSED
 
BY
 
A
 
PROPANE
 
GAS
 
LEAK
INSTALL
 
A
 
GAS
 
DETECTING
 
WARNING
 
DEVICE
. S
INCE
 
RUST
 
CAN
 
REDUCE
 
THE
 
LEVEL
 
OF
 
ODORANT
 
IN
 
PROPANE
 
GAS
A
 
GAS
 
DETECTING
 
WARNING
 
DEVICE
 
IS
 
THE
 
ONLY
 
RELIABLE
 
WAY
 
TO
 
DETECT
 
A
 
PROPANE
 
GAS
 
LEAK
. C
ONTACT
 
A
 
LOCAL
 
PROPANE
 
GAS
 
SUPPLIER
 
ABOUT
 
INSTALLING
 
A
 
GAS
 
DETECTING
 
WARNING
 
DEVICE
.
WARNING
IMPORTANT NOTE: Propane gas conversion kits must be
installed to convert units to propane gas.
All propane gas equipment must conform to the safety
standards of the National Board of Fire Underwriters (See
NBFU Manual 58). Line pressure 11.3 - 14” w.c.
For satisfactory operation, propane gas manifold pressure
must be within 9.7 - 10.3 inches w.c. for high fire and within
6.7 - 7.3 inches w.c. low fire at the manifold with all gas appli-
ances in operation. Maintaining  proper gas pressure depends
on three main factors:
1. Vaporization rate, which depends on (a) temperature
of the liquid, and (b)  wetted surface area of the
container or containers.
2. Proper pressure regulation.
3. Pressure drop in lines between regulators, and
between second stage regulator and the appliance.
Pipe size required will depend on length of pipe run
and total load of all appliances.
T
ANKS
 
AND
 P
IPING
Complete information regarding tank sizing for
vaporization, recommended regulator settings and pipe
sizing is available from most regulator manufacturers and
propane gas suppliers.
Since propane gas will quickly dissolve white lead or most
standard commercial compounds, special pipe dope
must be used. Shellac base compounds resistant to the
actions of liquefied petroleum gases such as Gasolac
®
,
Stalactic
®
, Clyde’s
®
 or John Crane
®
 are satisfactory.
See following figure for typical propane gas piping.
200 PSIG
Maximum
5 to 15 PSIG
(20 PSIG Max.)
Continuous
11" W.C.
Second Stage
Regulator
First Stage
Regulator
TYPICAL PROPANE GAS PIPING
R
OOF
 T
OP
 L
OCATION
 
AND
 I
NSTALLATION
The gas supply piping location and installation for roof top
units must be in accordance with local codes or, in the ab-
sence of locals codes, with ordinances of the latest edition of
the National Fuel Gas Code (ANSI Z223.1).
A manual gas shutoff valve must be field installed external to
the roof top unit. In addition, a drip leg must be installed near
the inlet connection. A ground joint union connection is re-
quired between the external shutoff valve and the unit con-
nection to the gas valve to permit removal of the burner as-
sembly for servicing.
1. Route gas piping to unit so that it does not interfere
with the removal of access panels. Support and align
piping to prevent strains or misalignment of the
manifold assembly.
2. All units are furnished with standard female NPT pipe
connections. Connection pipe size is 3/4" NPT. The
size of the gas supply piping to the unit must be based
on length of run, number of units on the system, gas
characteristics, BTU requirement and available supply
pressure. All piping must be done in accordance with
local codes or, in the absence of local codes, with the
latest edition of the National Fuel Gas Code (ANSI
Z223.1).