Sequence Of Operation - STA-RITE MAX-E-THERM SR400LP Instructions D'installation

Air/Fuel Ratio Adjustment
NOTICE: 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 particular 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.
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:
Call Sta-Rite for a 5%-decrease Natural Gas orifice.
Repeat orifice installation, starting at Step 1, Page 2.
At Step 7, use the 5%-decrease replacement Natural Gas
orifice which should be stamped as shown:
Model No. Natural Gas Orifice Marked
SR200NA
SR333NA
SR400NA
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.
Cure:
Call Sta-Rite for a 5%-increase Natural Gas orifice.
Repeat orifice installation, starting at Step 1, Page 2.
At Step 7, use the 5%-increase replacement Natural Gas
orifice which should be stamped as shown:
Model No. Natural Gas Orifice Marked
SR200NA
SR333NA
SR400NA
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.
Inlet Pressure:
Min./Max. . . . . . . . . . . . . . . . . . . . . . . . . . . 4" / 14" WC
Manifold Pressure:
(Referenced to blower inlet tap). . . . . . . . . . . . . . -0.2" WC
Orifice Size
M .288
K .392
H .468
Orifice Size
L .302
J .412
G .492
Required Gas Input (BTU/Hr):
Model SR200 . . . . . . . . . . . . . . . . . . . . 200,000BTU/Hr
Model SR333 . . . . . . . . . . . . . . . . . . . . 333,000BTU/Hr
Model SR400 . . . . . . . . . . . . . . . . . . . . 399,990BTU/Hr

Sequence Of Operation

For detailed information, please refer to Sta-Rite Pool/Spa
Heater Training and Service Manual, publication no.
S5066.
An electronic temperature sensing thermistor in the mani-
fold adapter inlet controls the heater operation. When the
inlet water temperature drops below the temperature set on
the operating control, the burner controller supplies
power to the combustion air blower through a series of
safety interlocks. The interlocks consist of
• the pressure switch (PS), which senses that the pump is
running,
• the high limit switch (HLS), which opens if the heat
exchanger outlet temperature goes above 135°F (57°C),
and
• the automatic gas shutoff (AGS) switch, which opens if
the heat exchanger outlet temperature goes above 140°F
(60°C).
• the stack flue sensor, which opens if the flue gas tem-
perature exceeds 500°F (260°C).
The air flow switch (AFS) senses the pressure drop across
the air metering orifice. As soon as there is sufficient air
flow, the AFS closes, closing the circuit to the hot surface
ignition (HSI), which ignites the fuel mixture.
On a call for heat, the blower and HSI are energized. In
about 20 seconds, the gas valve opens and ignition occurs.
The HSI then switches to a sensing mode and monitors the
flame.
Parts List
Part Name
Gas Orifice - N.G. (Kit 77707-1331)
Converts SR/SRC200LP to Natural Gas
Gas Orifice - N.G. (Kit 77707-1321)
Converts SR/SRC333LP to Natural Gas
Gas Orifice - N.G. (Kit 77707-1311)
Converts SR/SRC400LP to Natural Gas
Gas Orifice O-Ring (All Kits)
Conversion Instructions, Propane to N.G.
Propane to N.G. Conversion Decal
5
Qty. Part No.
1 42001-0331
1 42001-0321
1 42001-0311
1 U9-370
1 S694
1 32165-4159