Rheem A180CL25E Installation Instructions Manual page 18

METER TIME IN MINUTES AND SECONDS FOR NORMAL
INPUT RATING OF FURNACES EQUIPPED FOR NATURAL
METER
INPUT
BTU/HR
CU. FT.
250,000 ONE
TEN
ONE
300,000
TEN
ONE
350,000
TEN
ONE
400,000
TEN
To adjust the pressure regulator, remove
the regulator vent cover and turn the
adjustment screw clockwise to increase
pressure or counterclockwise to decrease
pressure. See Figure 18B. Then replace
the regulator vent cover securely.
Any necessary major changes in the gas
flow rate should be made by changing the
size of the burner orifices. To change orifice
spuds, shut off the manual main gas valve
and remove the gas manifold.
For elevations up to 2,000 feet, rating plate
input ratings apply. For high altitudes
(elevations over 2,000 ft.), see conversion
kit index 92-21519-XX for derating and
orifice spud sizes.
Check of input is important to prevent
over-firing of the furnace beyond its
design-rated input. NEVER SET INPUT
ABOVE THAT SHOWN ON THE RATING
PLATE. Use the following table or
formula to determine input rate.
Heating Value of Gas
(BTU/Cu. Ft.) x 3600
Cu. Ft. Per Hr. Required =
Time in Seconds
(for 1 Cu. Ft.) of Gas
DO NOT OVERTIGHTEN DRAIN FITTING
FIGURE 19. CONDENSATE DRAIN
18
TABLE 5
OR LP GAS
HEATING VALUE OF GAS BTU PER CU. FT.
SIZE
900 1000 1040
MIN. SEC. MIN. SEC. MIN. SEC. MIN. SEC. MIN. SEC.
13.0 14.4
2 10 2 24 2
10.8 12.0
1 48 2 0 2
9.3 10.3
1 33 1 43 1
8.1 9.0
1 21 1 30 1
Start the furnace and measure the time
required to burn one cubic foot of gas.
Prior to checking the furnace input,
make certain that all other gas
appliances are shut off, with the
exception of pilot burners. Time the
meter with only the furnace in operation.
IMPORTANT NOTE FOR ALTITUDES
ABOVE 2,000 FEET (610 METERS):
The main burner orifices in your furnace
and in these kits are sized for the
nameplate input and intended for
installations at elevations up to 2,000
feet in the USA or Canada, or for
elevations of 2,000 - 4,500 feet (610 -
1,373 meters) in Canada if the unit has
been derated at the factory. For
elevations above 2,000 feet (610
meters) IN THE USA ONLY (see ANSI-
Z223.1), the burner orifices must be
sized to reduce the input 4% for each
1,000 feet (305 meters) above sea level.
1100 2500
15.0 15.8 36.0
30 2 38 6 0
12.5 13.2 30.0
5 2 12 5 0
10.7 1.3 25.7
47 1 53 4 17
9.36 9.9 22.5
36 1 39 3 45
NOTICE: DERATING OF THE HEATING
INPUT FOR HIGH ALTITUDE IN THE
FIELD IS UNLAWFUL IN CANADA
(REFER TO CAN/CGA 2.17). UNITS
INSTALLED IN ALTITUDES GREATER
THAN 2,000 FEET (610 METERS) MUST
BE SHIPPED FROM THE FACTORY OR
FROM A FACTORY AUTHORIZED
CONVERSION STATION WITH THE
HEATING INPUT DERATED BY 10% SO
AS TO OPERATE PROPERLY IN
ALTITUDES FROM 2,000 - 4,500 FEET
(610 - 1,373 METERS).
D.CONDENSATE DRAIN
The condensate drain connection of the
evaporator is threaded 1" -11
IMPORTANT: Install a condensate trap to
ensure proper condensate drainage. See
Figure 19.
1 / " NPT.
2