Slant/Fin VGH-299-CH Installation And Service Manual page 73

Boost function
The outdoor reset boost function increases the CH_Setpoint by a prescribed increment (Boost_Temperature_Incr)
if a call for heat continues beyond the pre-set time limit (Boost_Time_Delay).
Boiler Parameters
(25) Warm Weather Shutdn
(26) Boost Temp increment
(27) Boost Time Delay
(28) Night Setback Temp.
These are parameters (26) Boost Temp Increment and (27) Boost Time Delay.
And have a default value of
installer by increasing parameter 26 by a number of degrees. Also, the time can be set when this parameter will
be active in parameter 27 now set on 20 min.
CH_Setpoint increases again if the call for heat still is not satisfied in another time increment.
Setpoint adjustment
It is possible to adjust the calculated setpoint with parameter CH_Setpoint_Diff. The calculated setpoint can be
increased or decreased with a maximum of
and Reset_Curve_Boiler_Maximum) are respected while adjusting the setpoint.
Apart from the calculated setpoint the functionality is the same as described in § 12.7.1.
Adjustable Outdoor Reset parameters
Parameters
CH_Mode
Reset_Curve_Design_Boiler
Sets high boiler CH setpoint when outdoor temp. is
equal to Reset_Curve_Outdoor_Design.
Reset_Curve_Outdoor_Design
Sets the outdoor temp at which the boiler setpoint
must be high as set by Reset_Curve_Design_Boiler.
Reset_Curve_Boiler_Mild_Weather
Sets low boiler CH setpoint when outdoor temp. is
equal to Reset_Curve_Outdoor_Mild_Weather.
Reset_Curve_Outdoor_Mild_Weather
Sets the outdoor temp at which the boiler setpoint
must be low as set by Reset_Curve_Mild_Weather.
Reset_Curve_Boiler_Minimum
Sets the lower limit for the CH setpoint (minimum).
Reset_Curve_Boiler_Maximum
Sets the upper limit for the CH setpoint (maximum).
Warm_Weather_Shutdown
Set max. outdoor temp. Above this temperature heat
demand is blocked.
Boost_Temperature_Incr
CH setpoint increment when heat demand
remains beyond Boost_Time_Delay.
Boost_Time_Delay
CH_Setpoint_Diff
Adjusts the calculated CH setpoint.
Table 12. 12
Status variables
Actual_CH_Setpoint
Calculated CH setpoint, based on outdoor reset curve.
Table 12. 13
72 °F ▲
0 °F
20 min
7 °F ▼
Picture 12.14
0 °F (0° C) and 20 min, so the function is switched off and can be activated by the
18 °F (10 °C). The CH setpoint limits (Reset_Curve_Boiler_Minimum
Level Default Value
2: Installer 1
2: Installer 176
2: Installer 23 ºF (-5 ºC)
2: Installer 104 ºF (40 ºC)
2: Installer 68 ºF (20 ºC)
2: Installer 86 ºF (30 ºC)
2: Installer 194
2: Installer 72 ºF (22 ºC)
2: Installer 0
2: Installer 20 min.
1: User 0 ºF (0 ºC)
E93.1601EN032.C VGH installation manual
Range
Mode 0-5
ºF (80 ºC) 32.....176 ºF (0.....80 ºC)
-4.....41 ºF (-20.....5 ºC)
32.....104 ºF (0.....40 ºC)
32.....86 ºF (0.....30 ºC)
68.....194 ºF (20.....90 ºC)
ºF (90 ºC) 68.....194 ºF (20.....90 ºC)
32.....95 ºF (0.....35 ºC)
ºF (0 ºC) 0.....36 ºF (0.....20 ºC)
1 – 120 min.
-18.....+18 ºF (-10.....+10 ºC)
Range
68...194 ºF (20.....90 ºC)
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