Appendix—Timeclock
the unit will respond differently to changing conditions and maintain a higher comfort level.
For unoccupied operation or “no load” conditions, a lower comfort level is provided. The load can be switched off by using the program for periods when the room will be unoccupied.
Note: If the room will be unoccupied, the time clock should be programmed accordingly to conserve energy. The position of the outside damper can allow too much outside air in an unoccupied space if the unit’s time clock is set for “load” or occupied mode and can result in unnecessary unit cycling and undesirable heat transfer.
Remember that the program is easily changed and can also be overridden after it is initially set.
1.Press the Prog. key. Spaces or fields for entering time (hours and minutes) appear as dashes separated by a colon.
2.Press Prog. again. The num- ber of free (available) pro- grams is given in this case to be “Fr20” or 20.
3.Press Prog. again to return to the event time mode.
4.Toggle the “Load” key on ( O ) 1or off (O) to link the time with the action.
In the example from the pre- ceding step, you would set the load ON.
5.Enter the time for the first pro- gram event.
For example, should you want the unit to operate under load for an occupied period at 8:00 a.m., enter “08:00” AM on the display using the h and m keys. Better yet, enter the time
a half hour or so before the arrival of people, so the unit will bring the room up (or down” to the preset occupied temperature setpoints).
6.If the program event you just entered will be the same every day (as indicated by all seven day numbers at the top of the display) you can press Prog. to lock in that event and go to the next event. If not and the program will vary during the week (e.g. different program for the weekend), don’t press Prog. go to the following step.
Note: If you press Prog. by mistake, simply continue to press Prog. until the event comes up in review and make the change.
7.With the time and hour for the event set, select the day or days for which the event applies by pressing the Day key. Toggling the Day key gives you ten options for indi- vidual days or combinations that can be applied. Select one and lock it in by pressing Prog.
In the example, if you only want the unit to operate under load for the time set for week- days, you would select “1 2 3 4 5” by pressing Day, then select another program event for the weekend.
8.Repeat the preceding steps to set the next program event. A “load: event is followed by an “unload” event. For example if the unit is programmed for a load condition in the morning, you could program the unit to unload later in the day or at night when the room will become unoccupied for a period. If the occupied and unoccupied periods vary widely but predictably, you can program a cycle of events
during any day or combination of days (up to 20 events)
9.Note: If only one event is pro- grammed, the unit will remain in that load or unload condi- tion all the time.
10.When all the events are pro- grammed, press the (¹) (run) key for normal operation. The current time as set will be dis- played, along with the run symbol (¹).
Review and Change Programs
To review a program and events at any time, press Prog . at any time. Programs events will be displayed in the sequence they were entered with repeated presses of Prog.
To change a program, select the event as in the previous paragraph and alter the new data (day, hour minute) as desired to overwrite the old program. Press Prog to store the data.
To delete a program event, select the event again and press h and m until dashes appear in the time dis- play. Press either Prog. or ( ¹) until the dashes flash in the display.
To reset all program data, press Res.
Override Program (Manual Operation)
While in the Run mode (¹ symbol
in display), press the hand 
key to reverse the load status (e.g. if the load was ON, it is now OFF). A
hand symbol 
appears to indi- cate the override is active.
At the next scheduled event, auto- matic (program) control will re- sume eliminating the override.
To switch the load permanently
ON, press the 
key a second time. [ O ] appears in the display.
66 |