28
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
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 35
The gas piping may enter the left or right side of the furnace cabinet. The installer must supply rigid pipe long enough to reach
the outside of the cabinet to seal the grommet cabinet penetration. A semi-rigid connector to the gas piping can be used outside the
cabinet per local codes. 1/2” NPT pipe and fittings are required. For models with an “L” shaped manifold, a 4 1/2” long nipple
is required. For models with a hook shaped manifold, a 2” long nipple is required.
A semi-rigid connector to the gas piping can be used outside the cabinet per local codes. From the elbow, the length of pipe
and the fittings required will vary by the side chosen, location of union and cabinet width. The union may be placed inside or
outside of the cabinet.
G
AS
P
IPING
C
HECKS
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).
P
ROPANE
G
AS
T
ANKS
AND
P
IPING
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.
For satisfactory operation, propane gas pressure must be 10” WC
at the furnace manifold with all gas appliances in operation. Main-
taining proper gas pressure depends on three main factors:
1. Vaporization rate, depending on temperature of the liquid,
and “wetted surface” area of the container 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 vaporization, rec-
ommended 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 stan-
dard commercial compounds, special pipe dope must be used. Al-
ways use a pipe thread sealant approved for all gases.
Refer to the illustration for typical propane gas installations and
piping.
