LAARS NeoTherm NTV (Sizes 150–285 MBTU/h) - Service Manual - Manual (Page 89)

79 Service Manual NeoTherm 80 - NeoTherm 285
Removing and Replacing
the SOLA Controller
All of the NT units use the SOLA controller. This procedure explains how
to remove and replace this controller.
Notice that, as installed in the NT unit, the SOLA controller is mounted
“upside down.” This does not affect the way the controller operates.
If you order a replacement, the SOLA controller will arrive with the EE-
PROM (programming software) already installed. The programming is
different from one type of NT unit to the next. This means that the SOLA
controllers are not interchangeable. When you order the replacement,
you must specify the exact type of NT unit you have.
Tools and equipment required
• 1/4” socket
Procedure
1. Before you begin, record all of the existing control settings, if pos-
sible. This will allow you to re-enter the settings after you install the
new controller. Record the current settings for temperature set-
points, outdoor reset, and lead/lag.
2. Turn off power to the system. Use the main disconnect switch
mounted above the front panel.
3. Remove the front panel from the unit by pulling it straight out.
4. Disconnect the wires and cables leading to the unit:
At the top of the controller:
• Disconnect the green connector. (Notice that this is plugged into
the right end of the socket. Be sure to replace it in the correct posi-
tion.)
On the left side of the controller (reading top to bottom):
• Disconnect connector CP10 from J10
• Disconnect connector CP9 from J9
• Disconnect connector CP8A from J8 (upper part)
• Disconnect connector CP8B from J8 (lower part)
On the bottom of the controller:
• Unplug connector J2
• Unplug connector J1
Fig. D9-1 - Honeywell SOLA
controller
D9