Pentair ETi 400 - Sequence of Operation

Rev. C 4/2017 ETi 400 High Efficiency Pool and Spa Heater Installation and User’s Guide
17
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), which senses that the pump is running,
• the tridicator gauges (2) which monitors the water temperature in degree Fahrenheit and pressure in psi.
• the high limit switch (HLS), which opens if the heat exchanger outlet temperature goes above 135° F (57° C), and
• the two air ow switches (AFS), sense the pressure drop across the air metering orices.
• the two thermal fuses (TF) open if the ue gas temperature reaches 187° F (86° C).
• the automatic gas shut-off (AG1, AG2) switches, which open if the heat exchanger outlet temperature goes above
150° F (66° C).
• the oat switch (FS) which opens if the condensate overows at the oat switch due to blockage in the condensate
drain hose or neutralizer cartridge.
• the stack ue sensors (SF1, SF1), which shut down the heater if the ue gas temperature reaches 170° F (77° C).
The air ow switches (AFS) sense the pressure differential between both of the air metering orices. As soon as there is
sufcient air ow, the AFS closes, completing the circuit to the Fan Conrol 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
Section 2: Installation Instructions
The installation instructions contained in this manual are designed for use by qualied personnel only, trained especially
for installation of this type of heating equipment and related components. Some states require installation and repair by
licensed personnel. If this applies in your state, be sure your contractor bears the appropriate license. See Figure 9, 10
& 11 for Outdoor and Indoor installations, dimensions and orientation of the heater.
SPECIFICATIONS
Figure 9.
Dimensions in Millimeters / Inches
Heater Top View
762
30.0
863.6
34.0
1012.8
39.9
548.1
21.6
664.9
26.2