Boiler Resistance Graph Vgh 500 Ch; Minimum Required Circulator Head; Modulating Circulator For Ch Demand; Modulating Circulator Modes - Slant/Fin VGH-299-CH Installation And Service Manual

8.1.3 B
OILER RESISTANCE GRAPH
35
30
25
20
15
10
5
0
0 10

Minimum required circulator head.

Boiler at flow rate
[gpm]
VGH 299 CH 27
VGH 399 CH 36
VGH 500 CH 45
Table 8. 1

Modulating circulator for CH demand

It is possible to connect a PWM circulator. The control supports PWM modulation for the general circulator.
Parameter 136 has to be set to modulating (Factory set to on/off circulator) when using a modulating circulator
The boiler circulator is modulated when there is a demand for CH.
During any other demand, the PWM circulator will run at a fixed speed set by the Default Duty cycle parameter.
How the circulator is modulated is controlled with the Modulating_Pump_Mode setting.

Modulating circulator modes

There are several modulating circulator modes implemented in the software.
By selecting a different modulating circulator mode, the circulator behavior can be changed. The following
modulating circulator modes are available.
Modulating circulator mode
0: Disabled
1: Delta temperature modulation
2: Fixed 20% speed
3: Fixed 30% speed
4: Fixed 40% speed
5: Fixed 50% speed
6: Fixed 60% speed
7: Fixed 70% speed
8: Fixed 80% speed
9: Fixed 90% speed
10: Fixed 100% speed
Table 8. 2
30
VGH 500 CH
Resistance graph VGH 500 CH
35°F 25°F
20 30
Flowrate [gallons (US)/minute]
min required feet of head
33
38
36
Details
No circulator modulation; the PWM duty cycle is always 0%.
Calculated duty cycle to create a delta temperature between the T_Supply and T_Return sensor.
Fixed duty cycle of 20%.
Fixed duty cycle of 30%.
Fixed duty cycle of 40%.
Fixed duty cycle of 50%.
Fixed duty cycle of 60%.
Fixed duty cycle of 70%.
Fixed duty cycle of 80%.
Fixed duty cycle of 90%.
Fixed duty cycle of 100%.
E93.1601EN032.C VGH installation manual
20°F
Figure 8. 3
40 50