31
Gas Piping Checks
Before placing unit in operation, leak test the unit and gas
connections.
Check for leaks using an approved chloride-free soap and
water solution, an electronic combustible gas detector, or
other approved testing methods.
NOTE: Never exceed specified pressures for testing.
Higher pressure may damage the gas valve and cause
subsequent overfiring, resulting in heat exchanger
failure.
Disconnect this unit and shutoff valve from the gas supply
piping system before pressure testing the supply piping
system with pressures in excess of 1/2 psig (3.48 kPa).
Isolate this unit from the gas supply piping system by closing
its external manual gas shutoff valve before pressure testing
supply piping system with test pressures equal to or less than
1/2 psig (3.48 kPA).
T
O
AVOID
THE
POSSIBILITY
OF
EXPLOSION
OR
FIRE
,
NEVER
USE
A
MATCH
OR
OPEN
FLAME
TO
TEST
FOR
LEAKS
.
WARNING
I
F
THE
GAS
FURNACE
IS
INSTALLED
IN
A
BASEMENT
,
AN
EXCAVATED
AREA
OR
CONFINED
SPACE
,
IT
IS
STRONGLY
RECOMMENDED
TO
CONTACT
A
PROPANE
SUPPLIER
TO
INSTALL
A
GAS
DETECTING
WARNING
DEVICE
IN
CASE
OF
A
GAS
LEAK
.
S
INCE
PROPANE
GAS
IS
HEAVIER
THAN
AIR
,
ANY
LEAKING
GAS
CAN
SETTLE
IN
ANY
LOW
AREAS
OR
CONFINED
SPACES
.
P
ROPANE
GAS
ODORANT
MAY
FADE
,
MAKING
THE
GAS
UNDETECTABLE
EXCEPT
WITH
A
WARNING
DEVICE
.
•
•
WARNING
Propane Gas Tanks and Piping
A gas detecting warning system is the only reliable way
to detect a propane gas leak. Rust can reduce the level
of odorant in propane gas. Do not rely on your sense
of smell. Contact a local propane gas supplier about
installing a gas detecting warning system. If the presence
of gas is suspected, follow the instructions listed in the
Safety Considerations section of this manual.
All propane gas equipment must conform to the safety
standards of the National Board of Fire Underwriters,
NBFU Manual 58.
CANADA: National Standard of Canada, Natural Gas and
Propane Installation Code (NSCNGPIC) CSA B149.1-15.
200 PSIG
Maximum
5 to 15 PSIG
(20 PSIG Max.)
Continuous
11" W.C.
Second Stage
Regulator
First Stage
Regulator
Propane Gas Installation (Typ.)
Figure 41
For satisfactory operation, propane gas pressure must be
10” WC at the furnace manifold with all gas appli ances in
operation. Maintaining proper gas pressure depends on
three main factors:
1. Vaporization rate, depending on temperature of the
liquid, and “wetted surface” area of the con tainer or
containers.
2. Proper pressure regulation. (Two-stage regulation is
recommended for both cost and efficiency).
3. Pressure drop in lines between regulators, and
between second stage regulator and the appliance.
Pipe size will depend on length of pipe run and total
load of all appliances.
Complete information regarding tank sizing for vaporiza-
tion, recommended regulator settings, and pipe sizing is
available from most regulator manufacturers and propane
gas suppliers.
Since propane gas will quickly dissolve white lead and
most standard com mercial compounds, special pipe dope
must be used. Always use a pipe thread sealant approved
for all gases.
Refer to the illustration for typical propane gas
installations and piping.
N
EVER
ALLOW
THE
PRODUCTS
OF
COMBUSTION
,
INCLUDING
CARBON
MONOXIDE
,
TO
ENTER
THE
RETURN
DUCT
WORK
OR
CIRCULATION
AIR
SUPPLY
.
WARNING
CIRCULATING AIR & FILTERS
Duct work - Air Flow
Duct systems and register sizes must be properly
designed for the CFM and external static pressure rat ing
of the furnace. Design the ductwork in accor dance with the
recommended methods of “Air Conditioning Contractors
of America” Manual D.
