Slant/Fin VGH-299-CH, Installation And Service Manual

Page: 73 / 128

E93.1601EN032.C VGH installation manual 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 72 °F
▲
(26) Boost Temp increment 0 °F
(27) Boost Time Delay 20 min
(28) Night Setback Temp. 7 °F ▼
These are parameters (26) Boost Temp Increment and (27) Boost Time Delay.
And have a default value of
0 °F (0° C) and 20 min, so the function is switched off and can be activated by the
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
18 °F (10 °C). The CH setpoint limits (Reset_Curve_Boiler_Minimum
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 Level Default Value Range
CH_Mode 2: Installer 1 Mode 0-5
Reset_Curve_Design_Boiler
Sets high boiler CH setpoint when outdoor temp. is
equal to Reset_Curve_Outdoor_Design.
2: Installer 176 ºF (80 ºC) 32…..176 ºF (0…..80 ºC)
Reset_Curve_Outdoor_Design
Sets the outdoor temp at which the boiler setpoint
must be high as set by Reset_Curve_Design_Boiler.
2: Installer 23 ºF (-5 ºC) -4…..41 ºF (-20…..5 ºC)
Reset_Curve_Boiler_Mild_Weather
Sets low boiler CH setpoint when outdoor temp. is
equal to
Reset_Curve_Outdoor_Mild_Weather.
2: Installer 104 ºF (40 ºC) 32…..104 ºF (0…..40 ºC)
Reset_Curve_Outdoor_Mild_Weather
Sets the outdoor temp at which the boiler setpoint
must be low as set by Reset_Curve_Mild_Weather.
2: Installer 68 ºF (20 ºC) 32…..86 ºF (0…..30 ºC)
Reset_Curve_Boiler_Minimum
Sets the lower limit for the CH setpoint (minimum).
2: Installer 86 ºF (30 ºC) 68…..194 ºF (20…..90 ºC)
Reset_Curve_Boiler_Maximum
Sets the upper limit for the CH setpoint (maximum).
2: Installer 194 ºF (90 ºC) 68…..194 ºF (20…..90 ºC)
Warm_Weather_Shutdown
Set max. outdoor temp. Above this temperature heat
demand is blocked.
2: Installer 72 ºF (22 ºC) 32….. 95 ºF (0…..35 ºC)
Boost_Temperature_Incr
CH setpoint increment when heat demand
remains beyond
Boost_Time_Delay.
2: Installer 0 ºF (0 ºC) 0….. 36 ºF (0…..20 ºC)
Boost_Time_Delay 2: Installer 20 min. 1 – 120 min.
CH_Setpoint_Diff
Adjusts the calculated CH setpoint.
1: User 0 ºF (0 ºC) -18…..+18 ºF (-10…..+10 ºC)
Status variables Range
Actual_CH_Setpoint
Calculated CH setpoint, based on outdoor reset curve.
68...194 ºF (20.....90 ºC)
Picture 12.14
Table 12. 12
Table 12. 13