25
BOILER CONTROL FUNCTION - BOILER
HOLD TEMPERATURE
The boiler can maintain a minimum boiler temperature
based on the setting of Parameter 38. The burner will
modulate on low input firing rate when the supply tem-
perature of the boiler is measured below the parameter
setting.
Once the boiler supply temperature is measured 10
º
F
above the parameter setting for the Boiler Hold
Temperature, the heat request ends and the burner
shuts down. The CH circulator is off during the burner
firing as the boiler tries to maintain the boiler hold tem-
perature and there is no CH Block Time period at the
completion of the burner firing.
Parameter Adjustment
The parameter adjustment for CH Hold Temperature is
Parameter 38. Follow the steps given in Program
Access Section on page 2 until the display shows
P_38
. Release the STEP button and display should
show the factory setting. Use the + or - button to adjust
to the revised setting and press STORE to save the set-
ting.
The factory setting of 32
º
F is the
OFF
position of the
Boiler Hold Temperature feature. With this setting the
Boiler Hold Temperature feature is not applied.
SPACE HEATING APPLICATION - CH
REQUEST FOR HEAT SETUP
At the completion of a CH request for heat the amount of
time for delay in reacting to a secondary CH request for
heat can be determine and set. The “blocking” time fea-
ture prevents potential short cycling of the boiler.
During the blocking period the burner will not fire. Only
the CH circulator will begin circulating at the start of the
secondary CH request for heat.
Parameter Adjustment
The parameter adjustment for CH “Blocking” Time is
Parameter 28. Follow the steps given in Program
Access Section on page 2 until the display shows
P_28
. Release the STEP button and display should
show the factory setting. Use the + or - button to adjust
to the revised setting and press STORE to save the set-
ting.
The parameter setting is multiplied by 10.2 sec-
onds for the actual setting. For example if the
parameter setting is 3 and the actual time period
of the “blocking” time is 30.6 seconds.
NOTICE
Parameter
Factory
Setting
Minimum
Setting
Maximum
Setting
28
03
x 10.2 sec.
00
x 10.2 sec.
30
x 10.2 sec.
Parameter
Factory
Setting
Minimum
Setting
Maximum
Setting
38
32ºF
32ºF
176ºF
