Rapid 7500 136 Installation, operation & service manual - page 55
SECTION 11: G
AS
P
IPING
F
OR
G
AS
-F
IRED
A
IR
T
URNOVER
U
NITS
43 of 143
11.3 Gas Manifold Ventin
g
Vent
v
al
v
es fitted on XL-compliant manifolds m
u
st
b
e
piped to the atmosphere o
u
tside the str
u
ct
u
re. This is
the responsi
b
ility of the installer.
11.3.1 Main Gas Re
g
ulator Ventin
g
The main reg
u
lator
u
sed on 1¼" NPT and larger
manifolds m
u
st
b
e piped to the atmosphere o
u
tside
the str
u
ct
u
re. This is the responsi
b
ility of the installer.
11.3.2 Vent Line Installation
The follo
w
ing may
b
e
u
sed as a g
u
ideline for
installation,
bu
t all applica
b
le codes and reg
u
lations
m
u
st
b
e follo
w
ed.
• Nat
u
ral gas and LPG are toxic and flamma
b
le
s
ub
stances. They m
u
st
b
e released
w
here they
w
ill not ca
u
se personal inj
u
ry or property damage.
The end of the
v
ent line m
u
st
b
e located
w
here it
is safe to release gas.
• Pipe the
v
ent line o
u
tside the str
u
ct
u
re.
• Use as short a
v
ertical r
u
n of pipe as possi
b
le.
• Do not r
u
n pipe from a high point to a lo
w
er point
to a
v
oid o
b
stacles.
• Use a minim
u
m n
u
m
b
er of
b
ends.
• Do not do
w
nsize the pipe from the origination
point (m
u
st
b
e same size or larger).
• Make s
u
re
v
ent line is free from o
b
str
u
ctions.
• Do not gro
u
p lines together into a common
header.
• The o
u
tside termination m
u
st ha
v
e a
w
eatherproof cap or
b
e directed do
w
n
w
ard for
protection from the elements and m
u
st
b
e
screened to pre
v
ent the entry of any o
b
jects.
11.4 Gas Pipin
g
The factory piping terminates
w
ith a female pipe
connection in the pilot take off tee. The man
u
al main
gas sh
u
toff
v
al
v
e is shipped loose for field
installation. Be s
u
re that the f
u
el s
u
pply pipe
connected at this point is large eno
u
gh to ens
u
re the
proper gas flo
w
and line press
u
re at the inlet of the
u
nit. The piping m
u
st comply
w
ith:
United States: Refer to NFPA 54/ANSI Z223.1 - latest
re
v
ision, National F
u
el Gas Code.
Canada: Refer to CSA B149.1 - latest re
v
ision,
Nat
u
ral Gas and Propane Installation Code.
Gas s
u
pply piping m
u
st conform to
b
est
bu
ilding
practices and local codes. D
u
ring installation of the
gas piping,
b
e s
u
re that no piping restricts
accessi
b
ility to the air t
u
rno
v
er
u
nit or its remo
v
a
b
le
access doors.
Locka
b
le man
u
al sh
u
t-off
v
al
v
e m
u
st
b
e added
b
y the
installer in compliance
w
ith Occ
u
pational Safety and
Health Administration (OSHA) reg
u
lations.
11.5 Pressure Test Ports
There are 3/8" NPT and 1/4" NPT press
u
re test ports
located on the manifold. The test ports are a
v
aila
b
le
to meas
u
re the manifold inlet gas press
u
re and the
bu
rner gas press
u
re d
u
ring
bu
rner set
u
p.
11.5.1 Manifold Inlet Gas Pressure - 3/
8
" NPT
The press
u
re test port for meas
u
ring manifold inlet
press
u
re is located on the pilot tee
w
hich is located
on the manifold inlet tee. Refer to the air t
u
rno
v
er
u
nit
rating plate for the accepta
b
le inlet gas press
u
re.
FIGURE 26: Test Port Location
11.5.2 Burner Gas Pressure - 1/4" NPT
The press
u
re test port for meas
u
ring
bu
rner gas
press
u
re is located at the
bu
rner inlet orifice tee.
Refer to the air t
u
rno
v
er
u
nit rating plate for the
bu
rner press
u
re req
u
ired for high fire.
Test Port