Specifications

14
8. PROGRAM THE CONTROLS (continued)
Please note that in operating mode to hold the
display on the value the user can press and hold
either the Up ñ or Down ò keys and the value
will be continuously shown. This may be helpful in
watching a value “live”.
Changing the Adjustable Parameters
To adjust the Parameters such as High Limit
Setpoint and High Limit Differential:
1. Access the adjustment mode by pressing
and holding the Up ñ, Down ò, and “I”
keys simultaneously for three (3) seconds.
This procedure is intended to discourage
unauthorized changes or accidental changes
to limit settings.
2. Press the "I" key to display available
Adjustment Mode options. Select an option.
Adjustment Mode Options
HL_
140-220°F Adjust High Limit Setting
dF_
10-30°F Adjust High Limit Differential
Or_
0-10 minutes Circulator Overrun Time
PP_
2-20 minutes Circulator Pre-purge Time
St_
140-180°F Start Temperature
Pt_
On or off Priority time
dh_
dh or tt2 DH Terminal Function
rst
Reset Lockout
f-C
F or C Select degrees F or C Mode
bac
Back to Operating Mode
3. Press the Up ñ and Down ò keys to adjust
the displayed item to the desired value.
4. To return to the normal operating mode from
the Adjustment Mode, when the "bAc” option
is displayed, press either the Up ñ or Down
ò key. If no keys are pressed, after ve (5)
minutes the control will automatically return
to the Operating Mode.
More Information about Adjustable Parameters
1. High Limit (HL_)
The control is factory programmed with a
High Limit Setpoint of 180°F. The burner
turns "off" when the boiler temperature (bt)
is above Operating Setpoint. The Operating
Setpoint (SP) will equal the High Limit
Setpoint unless an IQ Outdoor Reset IQ
Option Card is installed.
The Outdoor Reset IQ Option Card reduces
the Operating Setpoint to regulate heat
delivery, increase home comfort and
save energy. Refer to the Appendix I for
additional information. The High Limit
Setpoint is adjustable between 140° and
220°F.
2. Differential (df_)
The control is factory programmed with a
Differential of 15°F. The Differential is the
number of degrees the boiler temperature
must decrease below the Operating Setpoint
before the boiler can restart. The differential
is adjustable between 10° through 30°F.
3. Circulator Overrun Time (OR_)
The control is factory programmed with
a Circulator Overrun Time of 0 minutes.
Circulator Overrun Time (also called
“circulator off delay” or “circulator post
purge”) continues circulator operation after
a call for heat has ended, sending excess
heat from the boiler into the system. Ensure
system piping and zone panel settings allow
water ow to the priority zone after the call
for heat ends. The Circulator Overrun Time
is adjustable between 0 through 10 minutes.
4. Circulator Pre-purge Time (PP_)
When the boiler is warm (boiler water
temperature higher than 140°F (adjustable
using Start Temperature parameter)) and
there is a thermostat call for heat, the
system circulator is started and boiler ring
is delayed Circulator Pre-purge minutes. If
the temperature drops below 140°F or there
is a DHW call for heat the boiler is started
without delay. Additionally, the boiler is
started without delay if the thermostat call
for heat is initiated when the boiler water
temperature is less than 140°F. This
feature helps save energy by satisfying
home heating needs with residual boiler
heat rather than cycling the boiler. The
Circulator Pre-purge time has a factory
setting of 2 minutes and is eld adjustable
between 2 and 20 minutes. When reset card
is installed, pre-purge time may be adjusted
down to zero (0) minutes. Refer to Table 8a.