Temperature Control Operation; Set Point Adjustment; Fahrenheit V. Celsius; Heating Mode - Hayward H250FDN Service & Installation Manual



TEMPERATURE CONTROL OPERATION:

The heater is equipped with a Temperature Control for controlling the pool and spa water temperatures.
Individual pool and spa set points can be entered using the keypad (see Figure 7 for the location of the key-
pad and Figure 5 for a view of the keypad). The control displays the pool or spa water temperature and, if
needed, diagnostic information.
Figure 35: Keypad
OPERATION:

SET POINT ADjUSTMENT:

The set point temperature is displayed by pressing the "UP" or "DOWN" buttons while in "POOL" or
"SPA" mode. The set point will blink while it is displayed. Further pressing of the "UP" or "DOWN" buttons
will adjust the set point temperature up or down as desired. The set point range is between 65°F (18°C) and
104°F (40°C).
FAHRENHEIT VERSUS CELSIUS:
The temperature can be displayed in Fahrenheit or Celsius. TO change the display, use the "MODE" but-
ton to place the heater in "STANDBY". Then press and hold the "UP" and "DOWN" buttons until the display
shows the °F/°C selection. Press the "DOWN" button to toggle between selections. To accept the selection,
press the "MODE" button. If the user does not act, the selection will be automatically accepted after 0 sec-
onds.

HEATING MODE

The control continually compares the water temperature with the set point and the high limit temperature. When
the water temperature is more than 1° below the set point a call for heat is generated and a heating cycle is initi-
ated.
1. The control checks for open contacts at the blower vacuum switch.
. The control energizes the blower and the igniter. The igniter heat-up time is approximately 0 seconds.
The blower is running a pre-purge cycle during this time.
. The control checks for closed contacts at the blower vacuum switch.
. When the igniter reaches the proper temperature a -second trial for ignition begins. The control opens
the gas valve and monitors flame current. The igniter is turned off when flame is sensed or after 4 sec-
onds.
5. The blower vacuum switch, the temperature limit switches, the vent pressure switch, the water pressure
switch, the water temperature sensors, and the flame sensor are constantly monitored during a call for
heat to assure the heater is operating properly.
:
USE ONLY HAYWARD GENUINE REPLACEMENT PARTS
Pomona, CA Clemmons, NC Nashville, TN
Tel: 908-351-5400 www.haywardpool.com