User Guide

41
103876-08 - 1/19
CL
Installation & Service Manual
c. Press the Up ñ and Down ò keys to adjust
the displayed setpoint to the desired value.
d. To return to the normal operating mode from
the Adjustment Mode, when the "bc” option
is displayed, press either the Up ñ or Down
ò key. If no keys are pressed, after five (5)
minutes the Boiler Control will automatically
return to the Operating Mode.
6. More Information about Adjustable Parameters
a. High Limit (HL_)
The Boiler Control is factory programmed
with a High Limit Setpoint of 180°F. The
boiler turns "off" when the boiler water
temperature (bt) is above this value. The
High Limit setpoint is adjustable between
140° and 240°F. The Operating Setpoint
(P) will equal the High Limit Setpoint.
b. High Limit Differential (HdF)
i. The Cold Start Boiler 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°
and 30°F.
ii. On Warm Start Boiler Control the High
Limit Differential is not adjustable and is
fixed at 10°F.
c. Low Limit (LL_)
The Warm Start Boiler Control is factory
programmed with a Low Limit Setpoint
of 110°F. On falling temperature the
boiler turns “on” and the “ZC” terminal
and System Circulator outputs are de-
energized when the boiler temperature is
less than the Low Limit Setpoint less the
differential. On a rising temperature when
the boiler temperature is above the Low
Limit Setpoint the boiler turns “off”, the “ZC”
terminal output is energized and the System
circulator is enabled to respond to a call for
heat. The Low Limit Setpoint is adjustable
between 110°F and 220°F.
d. Low Limit Differential (Ldf)
The Warm Start Boiler Control is factory
programmed with a Low Limit Differential
Setpoint of 10°F. The Low Limit Differential
is the number of degrees the boiler
temperature must decrease below the Low
Limit Setpoint before the Warm Start Boiler
Control takes actions to warm the boiler.
These actions include starting the burner
and stopping water flow through the boiler.
The Low Limit Differential is adjustable
between 10°F and 25°F.
e. Circulator Overrun Time (OR_)
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 priority zone.
Ensure system piping and zone panel
settings allow water flow to the priority zone
after the call for heat ends. The Circulator
Overrun Time has a factor setting of 0
minutes and is field adjustable between 0
and 10 minutes.
f. 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
firing is delayed 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 field adjustable between 2
and 20 minutes. Refer to Table 8.
The Warm Start Boiler Control Pre-purge
Time is factor set to 0 minutes.
6 Operating (continued)
Call for
Heat
ZC and ZR
Terminal
Function
(ZC_)
Boiler
Temp.
Boiler Status,
(B1 Output)
TT= on
--
< 140 Start with no delay
TT = on
--
>140 Start after 2 minute delay
ZR = on
ZC_ = ZR
<140 Start with no delay
ZR = on
ZC_ = ZR
>140 Start after 2 minute delay
ZR = on
ZC_ = DH
<140 Start with no delay
ZR = on
ZC_ = DH
>140 Start with no delay
Table 8: Circulator Pre-Purge Time Example,
Parameter PP_= 2 Minutes