Lochinvar Harmony - Manual (Page 25)

25
RESET SETTINGS
RESET RATIO Default 1:1
• The Reset Ratio controls how much heat will be added based on
outdoor temperature. The Reset Ratios are shown as Outdoor
Temperature:Water Temperature.
• A 1:1 Reset Ratio signifies for each degree it gets colder outside, the
Calculated water temperature will raise 1 degree.
• The other Reset Ratios are adjustable from 1:4 to 4:1.
• The Reset Ratio curves start at 70°F. At 70°F the Harmony will
require 100°F water. Note that this is not the point where the
Harmony will begin giving heat. That point is determined by the
Outdoor Cutoff (next page). Also note that this starting point can be
changed by adjusting the Offset (below).
• For new installations with standard baseboard heating, begin with a
Reset Ratio of 1:1.
• For new installations with radiant heat, begin with a Reset Ratio
curve of 2:1.
• Adjust the Reset Ratio value in cold weather. If the ambient indoor
temperatures are cold in the cold weather, pick the next higher Reset
Ratio (that is, go from 1:1 to 1:1.25). If the ambient building tempera-
tures are warm in the cold weather, pick the next lower Reset Ratio
(from 1:1 to 1.25:1).
• After adjusting the Reset Ratio curve, wait at least 24 hours before
making another adjustment.
• To adjust the Reset Ratio, from the main display press the ADJUST/
SELECT knob to obtain the Settings menu. Select Set Point. The
Reset Ratio choices will now be shown.
OFFSET Default 0
• The Offset value moves the starting point of the Reset Ratio curves
(see charts below).
• Therefore, any change made to the Offset will immediately change
the value of the Harmony Set Point water temperature by the same
amount.
• For example, if the calculated Set Point water temperature were 150°F
based on the specific outdoor temperature and Reset Ratio, then
increasing the Offset from 0°F to 10°F would increase the Set Point
water temperature to 160°F.
Outdoor Temperature (in °F)
70 60 50 40 20 30 0 -10 10 -20
Water
T
e
mper
atur
e (
in °F
)
100
120
110
130
140
150
160
180
170
190
200
210
220
1:4 1:3 1:2 1:1.5
1:1.25
1:1
1.25:1
1.5:1
2:1
3:1
4:1
RESET RATIOS
With a -20° Offset, the ratio curves
begin at 80° Water Temperature.
With a 0° Offset, the ratio curves
begin at 100° Water Temperature.
With a +20° Offset, the ratio curves
begin at 120° Water Temperature.
Outdoor Temperature
Water
Tem
per
atur
e
70 40 50 60
130
120
110
100
1:3
4:1
1:1
Outdoor Temperature
Water
Tem
per
atur
e
70 40 50 60
110
100
90
80
1:3
4:1
1:1
Outdoor Temperature
Water
Tem
per
atur
e
70 40 50 60
150
140
130
120
1:3
4:1
1:1
--- SETTINGS ---
>Set Point
Gain
Lead Stage
--- RESET RATIO ---
1.00°OD = 1.25°Sys
>1.00°OD = 1.00°Sys
1.25°OD = 1.00°Sys
--- RESET RATIO ---
1.00°OD = 1.50°Sys
>1.00°OD = 1.25°Sys
1.00°OD = 1.00°Sys
Temp
B C D
OFF OFF OFF OFF
--- RESET RATIO ---
1.00°OD = 1.50°Sys
>1.00°OD = 1.25°Sys
1.00°OD = 1.00°Sys
PRESS TO SELECT
ADJUST
Press to
show
Settings
PRESS TO SELECT
ADJUST
Press to
select
Set Point
PRESS TO SELECT
ADJUST
Turn to
scroll
PRESS TO SELECT
ADJUST
Press to
select
new
RESET SETTINGSRESET SETTINGSRESET SETTINGSRESET SETTINGSRESET SETTINGS