John Wood Commercial - 300-400K BTU - Manual (Page 41)

41
multifunctional, their current function is defined by the text
that appears directly above each button on the LCD screen.
the desktop screen
During normal operation the control system will display the
"Desktop" screen on the LCD which is the default screen. The
control system will return to the Desktop screen when there are
no active Fault or Alert conditions or when there has been no
user input for several minutes.
• Manufacturer and water heater model information is
displayed in Title bar at the top of the Desktop screen.
Menu titles are displayed in the Title bar when navigating
the control system menus.
• The first temperature shown on the Desktop screen, Tank
Temperature, is the temperature of the water inside the
water heater's storage tank.
• The second temperature shown on the Desktop screen
is the Operating Set Point. The Operating Set Point is the
temperature at which the control system will maintain the
water inside the storage tank.
• beneath the Operating Set Point is the "Status" line. The
Status line shows the current operational state of the
control system in real time, see Table 11 on page 43 for a
description of the various operational states.
• The Desktop screen also displays animated "Status Icons"
to convey operational information, see Table 10 on page
42 for descriptions of the Status Icons.
oVerView
The water heaters covered in this manual are equipped with an
electronic control system that regulates water temperature inside
the storage tank. Heating cycles and ignition are managed by
the control system. The ECO (energy cut out), flame sensor,
pressure switches and temperature probes are monitored by the
control system. The Combustion blower, igniter, 24 VAC gas
Valve and anode rods are all powered by the control system.
The main components of the control system are a uIM (user
interface module) and a CCb (central control board). The uIM
is located on the top front side of the water heater. The CCb is
mounted on top of the water heater inside a protective enclosure.
See Features And Components on page 7 for location of these
and all water heater components.
control system naVigation
All operational information and user settings are displayed and
accessed from the uIM. The uIM houses the control system's
LCD (liquid crystal display) and five snap acting (momentary)
user input buttons; an up, down and three (3) multi functional
operational buttons below the LCD, see Figure 55.
user input buttons
• The up and down buttons are used to navigate menus and
adjust user settings.
• The operational buttons are used to enter/exit menus,
select menu items, activate adjustment modes and confirm
or cancel new user settings. The operational buttons are
control system operation
Tank Temperature 103°F
Operating Set Point 120°F
Status: Heating
MENU HELP
GAS
OFF
O
N
MANUFACTURER / MODEL INFORMATION
LCD Screen
Information
Display
Status Icons
3 Operational buttons:
enter/exit menus,
select menu items,
activate adjustment modes,
confirm/cancel changes.
Up & Down buttons:
navigate menus,
adjust user settings
Title Bar
Operational buttons are multi functional. Their current function is defined by
the text that appears directly above each button on the LCD screen.
UIM (user interface module)
Desktop Screen Shown
UP
DN
figure 55