Pentair ETi 400 Guide D'installation page 14

14
Sequence of Operation
An electronic temperature sensing thermistor in the manifold adapter inlet
controls the heater operation. When the inlet water temperature drops below the
temperature set on the operator control panel, the control board supplies power
to the combustion air blowers through a series of safety interlocks. The heater
interlocks consist of;
• The two water pressure switches (PS) sense that the pump is running,
• The high limit switch (HLS) opens if the heat exchanger outlet temperature
goes above 135°F (57°C), and
• The two air flow switches (AFS) sense the pressure drop across the air
metering orifices.
• The two thermal fuses (TF) open if the flue gas temperature reaches
187°F (86°C).
• The automatic gas shut-off switches (AG1, AG2) open if the heat
exchanger outlet temperature goes above 150°F (66°C).
• The float switch (FS) opens if the condensate overflows at the float switch
due to blockage in the condensate drain hose or neutralizer cartridge.
• The stack flue sensors (SF1, SF1) shut down the heater if the flue gas
temperature reaches 170°F (77°C).
The air flow switches (AFS) sense the pressure differential between both of
the air metering orifices. As soon as there is sufficient air flow, the AFS closes,
completing the circuit to the Fan Control board. The gas ignition control then
opens the gas valve and the fuel mixture is ignited by the Direct Spark Ignition
(DSI). On a call for heat, the blowers are energized for 15 seconds, the gas
valve opens simultaneously as the direct spark igniters are energized, then
ignition occurs. The heater is equipped with a digital operating control that
enables the user to pre-set the desired pool and spa water temperatures. The
control enables the user to select between pool and spa heating, and features a
digital display that indicates the water temperature.
Heater Specifications
Inlet Pressure:
Min./Max:
Manifold Pressure:
Reference to Blower inlet tap:
Required Gas Input (BTU/Hr):
Parts List
Description
Direct Spark Igniters
Air Orifice
Gas Orifice (NL)
O-Ring
Installation Guide
Propane Conversion Label
ETi 400 Propane Conversion Kit Installation Guide
®
4" / 12" WC
-0.2" WC
399,990 BTU/Hr
Qty. P/N
2 476081
2 476064
2 476075
2 U9-370
1 476079
1 476078