HT# 059299-00 A
20%
20%
Purge
60%
100%
20%
20%
100%
Boiler A Modulating
Boiler B Modulating
Purge
Boiler B
MODULATING CONCEPT
SETTINGS:
Ignition % = 20%
Modulation Start % = 60%
Lag boiler drop= 40% x 60% = 24%
Modulation Increasing
Boiler A
20%
100%
20%
20%
24%
20%
at 20% until System
Sensor exceeds Target
at Ignition % while Lead
Boiler A modulates down
Decrease Modulation
Boiler A
Boiler B
When the load is reduced, the control will gradually decrease the lag boiler's modulation until it reaches its
lowest ring % The lag boiler will remain at the Ignition % while the control is reducing the lead boiler's
modulation When the lead boiler reaches 40% of the Modulation Start %, the control turns off the lag
boiler
The Multi-MOD Platinum has multiple operating modes that
satisfy most hydronic or steam systems When used to control
a hydronic system, it can change the target Set Point based
on outdoor temperature (Outdoor Reset) or it can modulate its
stages to achieve a xed Set Point
In Outdoor Reset, the Multi-MOD Platinum controls a hot water
heating system to provide a building with comfortable and even
heat levels It varies the temperature of the circulating heating
water in response to changes in the outdoor temperature The
heating water temperature is controlled through the modulation of
the stages
The Multi-MOD Platinum also controls the system-circulating
pump with an adjustable Outdoor Cutoff When the outdoor
temperature is above Outdoor Cutoff, the pump is off and no
heating water is circulated through the system When the outdoor
temperature drops below the Outdoor Cutoff, the system pump
output is activated and the heating water circulates through the
system The temperature of the heating water is controlled by the
Reset Ratio, Offset, Minimum Target, Maximum Target, and the
outdoor temperature
Reset Ratio (Outdoor : Water)
70 60 50 40 2030 0 -1010 -20
100
120
110
130
140
150
160
180
170
190
200
210
220
Water Temperature (in °F)
Reset Ratio Curves
Outdoor Temperature (in °F)
1:1.25
1:1
1.25:1
1.5:1
2:1
3:1
4:1
1:4 1:3 1:2 1:1.5
When a building is being heated, heat escapes through the walls,
doors, and windows to the colder outside air The colder the
outside temperature, the more heat escapes If you can input
heat into the building at the same rate that it is lost out of the
building, then the building temperature will remain constant The
Reset Ratio is an adjustment that lets the building achieve this
equilibrium between heat input and heat loss Outdoor reset is
the most efcient way a building can be heated
To Next Page
Loading...
Need help?
General