Daikin DCG Series, Installation And Maintenance Manual

Page: 13 / 38

11
NOTE: The unit gas supply entrance is factory sealed with plugs.
Keep plugs in place until gas supply is ready to be installed. Once
ready, replace the plugs with the supplied grommets and install
gas supply line.
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 appliances in op-
eration. 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 absence of locals
codes, with ordinances of the latest edition of the National Fuel
Gas Code (ANSI Z223.1).
A manual gas shut off 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 required be-
tween the external shut off valve and the unit connection to the
gas valve to permit removal of the burner assembly 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.