STA-RITE MAX-E-THERM SR400LP Instructions Pour L'installation page 3

4. Install a 1/8" NPT barbed fitting into the 'PRESSURE
TAP' port on the outlet side of the gas valve. Use a
flexible tube to connect it to the low side of a differen-
tial pressure gauge or a slope gauge . This gauge will
measure low (outlet) pressure.
5. Turn on the manual gas shutoff valve.
6. Before operating the heater, leak-test the heater and all
its gas connections with soapy water.
Risk of fire or explosion. Never test for
gas leaks with an open flame.
7. Turn on electricity to heater and start the pump.
8. Turn on the heater.
NOTICE: If you are using a slope gauge , close the
shutoff valve of the gauge to avoid pulling the liquid
out of the gauge when the blower starts.
9. After the burner lights, verify that the supply pressure is
within the range 4" to 14" wc. If the supply pressure drops
below this range when the burner ignites, the gas line
capacity may be inadequate, and should be increased.
Consult owner's manual for more information.
10. With the burner still on, disconnect the plastic hose
between the gas valve and "VENT" tap and the blower
mixer inlet. The pressure gauge should then read .2"
±.1" wc. (Since the pressure tap is connected to the
low side of the gauge, the pressure is actually nega-
tive.) If the pressure is outside the range listed, call the
factory at 1-800-752-0183. Do not try to adjust the
pressure yourself.
Air/Fuel Ratio Adjustment
Mixture Too Rich - (too much gas)
Symptoms:
A. CO too high or
2
B. O too low or
2
C. Burner emits a high pitched whine
Cure:
Install 5% - decrease orifice (see "Orifice Replacement
Procedure", at right).
At Step 7, use the 5%-decrease replacement orifice which
should be stamped as shown:
Table 1: 5% Decrease Orifice Sizes
Model 5% - Orifice
No. Code Marked
SR/SRC200NA
SR/SRC333NA
SR/SRC400NA, HD
SR/SRC200LP
SR/SRC333LP
SR/SRC400LP
Mixture too Lean - (not enough gas)
Symptoms:
A. CO too low or
2
B. O too high or
2
C. Burner sounds rough and pulsating or exhaust has a
highly acrid odor.
Orifice
Size
M .288
K .392
H .468
U .238
S .332
P .399
Cure:
Install 5% - increase orifice (see "Orifice Replacement
Procedure", below).
At Step 7, use the 5%-increase replacement Natural Gas
orifice which should be stamped as shown:
Table 2: 5% Increase Orifice Sizes
Model
No.
SR/SRC200NA
SR/SRC333NA
SR/SRC400NA, HD
SR/SRC200LP
SR/SRC333LP
SR/SRC400LP
NOTICE: If neither correction above produces satisfactory
combustion, consult your Sta-Rite distributor. The air/fuel
ratio is adjusted by replacing the gas orifice with an orifice
of the correct size.
Do not attempt to adjust the air/fuel mixture by altering gas or
air orifice sizes or by adjusting the gas input to achieve a par-
ticular gas input rate ("clocking the meter"), as the rate may
vary depending on elevation and local gas heating value.
Do not attempt to adjust the gas input outside of the speci-
fied range.
Orifice Replacement Procedure:
1. Turn off the electrical supply to the heater; turn off the
pump; turn off the manual gas supply valve to the
heater.
2. Unbolt and separate the top jacket halves.
3. Unscrew completely the 3/4" gas line union closest to
the combination gas control valve.
4. Loosen the 3/4" gas line union directly above the air
inlet tube (see Figure 3).
Swing Gas Line
to One Side
Air Inlet
Tube
Figure 3: Swing Gas Line Out of the Way
5. Loosen the pipe clamp holding the gas line to the
upper control support and swing the gas line loop out
of the way.
3
5% + Orifice Orifice
Code Marked Size
L .302
J .412
G .492
T .250
R .348
N .419
Remove
Orifice
2801 0497