Therma-Stor Products Group UA-150H - Manual (Page 9)

9 Ultra-Aire 150H Installer’s & Owner’s Manual
If the timer fails to operate or operates erratically, check that the
control panel receives 24Vac from the UA-150H. If 24Vac is present
at the control panel, reset the timer by pressing the reset button at
the bottom center of the timer face. The reset button is the small
recessed button with an R beneath it located below the 1…7 and h
buttons. Press the reset button in until the display clears. Release the
reset button. The display will reappear as 00:00. Resetting the timer
will clear the time and all program settings. After resetting the timer
follow the instructions below to set the correct time and ventilation
programs.
Setting The Time: The following instructions explain how to set the
ventilation timer. First, set the correct time on the timer by sliding the
switch in the upper right hand corner of the timer to the clock symbol
• and pressing the 1…7 (DAY), h (HOUR), and m (MINUTE) buttons.
Remember that this timer operates on a 24-hour (military time) clock.
Ventilation Schedule: Slide the switch in the upper right hand
corner to the program symbol P. “ON” will appear to the right of the
time and the number “1” will appear in the lower right hand corner
of the display. The “1” and “ON” signify the turn on time for the first
program. Press the 1…7 button to choose the days of the week for
this program. You can choose Mon.-Sun, Mon.-Fri., Sat-Sun, or any
single day of the week. The days chosen are shown along the top
of the display on the ventilation timer. Next press the h button to
set the hour for the start of the ventilation period. Remember that
this timer operates on a 24-hour clock. Then press the m button to
set the minutes past the hour to start the ventilation. Now, with the
ventilation start time set; press the I/O button. The word “OFF” should
appear to the right of the time and the number “1” should remain in
the lower right hand corner of the display. The “1” and “OFF” signify
the turn off time for the first program. Set the turn off time using the
1…7, h, and m buttons in the same way as described above and
continue on to the second through sixth programs. When setting the
ventilation programs, you can return to the current time display by
sliding the switch in the upper right corner of the timer to RUN. The
slide switch in the upper right must be set to RUN for the timer to
operate with the scheduled programs.
Automatic or Manual Mode: The slide switch in the upper left of
the timer is used to choose between automatic and manual operation
of the timer relay. When the slide switch in the upper left of the timer
is set to AUTO mode, the UA-150H will ventilate when the scheduled
programs call for ventilation. When the slide switch in the upper left
of the timer is set to manual (set to hand symbol on the right), the
operation of the timer is controlled by the I/O button only. Pressing
the I/O button will switch the ventilation timer between ON (detent)
and OFF (detent). As you press the I/O button, “ON” or “OFF” will
be displayed to the right of the time. The “ON” or “OFF” to the right
of the time will indicate if the ventilation timer is on or off. The I/O
button will manually override scheduled programs if the timer is in
AUTO mode.
4.6 Low Pressure Control
If the low side refrigerant pressure drops to 15 PSIG, the low-
pressure control opens and shuts off the compressor and impeller
fan. It is an automatically reset control that will close when the
pressure rises to 35 PSIG. Its primary function is to prevent damage
to the compressor if a leak develops in the refrigeration system. It
may also open if the unit is A) installed in a cool area (below 50 F)
or B) installed where it is below 40 F and then started. Under these
conditions, the unit will restart within several minutes. Until the unit
warms up, it may repeat the cycle several times.
FOR HVAC INSTALLER ONLY
Ultra-Aire 150H Installer’s & Owner’s Manual