Pentair ETi 250 - Sequence of Operation

ETi 250 High Efficiency Pool and Spa Heater Installation and User’s Guide
18
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 blower through a series of safety interlocks. The heater interlocks consist of:
• Water pressure switch (PS) - senses that the pump is running,
• Tridicator Gauge - which monitors the water temperature in degrees Fahrenheit and pressure in psi.
• High limit switch (HLS) - which opens if the heat exchanger outlet temperature goes above 135° F (57° C).
• Air ow switch (AFS) - which senses the pressure drop across the air metering orices.
• Thermal fuse (TF) - which opens if the ue gas temperature reaches 187° F (86° C).
• Automatic gas shut-off switch (AGS) - which opens if the heat exchanger outlet temperature goes above
150° F (66° C).
• Float switch (CFS) - which opens if the condensate overows at the oat switch due to blockage in the condensate
drain hose or neutralizer cartridge.
• Stack ue sensor (SFS) - which shuts down the heater if the ue gas temperature reaches 170° F (77° C).
The air ow switch (AFS) senses the pressure differential of the air metering orice. As soon as there is sufcient air
ow, the AFS closes. 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 blower is energized, the gas valve opens simultaneously as the direct spark igniter
energizes, 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.
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 10,
11 and 12 for Outdoor and Indoor installations, dimensions and orientation of the heater.
SPECIFICATIONS
Figure 10. Heater Top View.
Dimensions in Inches (Millimeters)
(788.95)
31.00
(635)
25.0
268.35
10.6
436.29
17.2
182.47
7.2
512.58
20.2
(635)
25.0
Installation