tekmar 155 Difference Setpoint Control - Manual (Page 3)

Δ T Setpoint. If the difference between the Source and Storage temperatures (ΔT) is greater than this setpoint, Relay 1 is turned on and
heat is transferred from the source to the storage.
Δ T Differential. This differential setting is used to prevent short cycling of the heat transfer device when the ΔT is near the ΔT setpoint.
Maximum Storage Setpoint. If the Storage temperature rises above this setpoint, Relay 1 is turned off.
Maximum Storage Differential. This differential setting is used to prevent short cycling of the heat transfer device when the Storage
temperature is near the Maximum Storage setpoint.
Minimum Source Setpoint. If the Source temperature drops below this setpoint, Relay 1 is turned off and Relay 2 operates according
to the requirements of the Draindown or Drainback system.
Minimum Source Differential. This differential setting is used to prevent short cycling of the heat transfer device when the Source
temperature is near the Minimum Source Setpoint.
Press and Release the “Item”
button to view the current
“Source” temperature.
When the control is powered-up,
all LCD segments are turned on
for 3 seconds.
The current “ΔT” is then
displayed. If Relay 1 is closed,
a “1” and the word “HEAT” is
displayed. If Relay 2 is closed,
a “2” is displayed.
Press and Release the “Item”
button to view the current
“Storage” temperature.
Press and Hold the
“Item” button to view
the “ΔT” setpoint.
Press and Hold the
“Up” button to view
the “Minimum Source”
setpoint.
Press and Hold the
“Down” button to view
the “Maximum Storage”
setpoint.
Press and Release
the “Item” button to
view the “Maximum
Source” temperature
measured since this
display was cleared.
Press and Release
the “Item” button to
view the “Minimum
Source” temperature
measured since this
display was cleared.
Press and Release
the “Item” button to
view the “ΔT•hours”.
The numbers shown
to the right indicate
5225 °F•hours.
The above Maximum or Minimum displays can be
reset by the following:
Press and Release
the “Item” button to
view the “Maximum
Storage” temperature
measured since this
display was cleared.
Press and Release
the “Item” button to
view the “Minimum
Storage” temperature
measured since this
display was cleared.
DISPLAY OPERATION
Note: The control changes from the above displays to the ΔT display if the buttons are left alone for 20 seconds.
Resetting Maximum or Minimum Displays Viewing programmed setpoints
While the control is displaying any of the current sensor
measurements, the setpoints can be viewed by the following:
Item
Item
Item
Item
Item
Item
Item
Item
Diff'l
F
ΔT
Source
Storage
Minimum
Maximum
ΔT • hours
Diff'l
F
ΔT
Source
Storage
Minimum
Maximum
ΔT • hours
Diff'l
F
ΔT
Source
Storage
Minimum
Maximum
ΔT • hours
Diff'l
F
ΔT
Source
Storage
Minimum
Maximum
ΔT • hours
Diff'l
ΔT
Source
Storage
Minimum
Maximum
ΔT • hours
thousands
Diff'l
ΔT
Source
Storage
Minimum
Maximum
ΔT • hours
units
F
Diff'l
F
ΔT
Source
Storage
Minimum
Maximum
ΔT • hours Diff'l
F
ΔT
Source
Storage
Minimum
Maximum
ΔT • hours
Item Item
Diff'l
F
ΔT
Source
Storage
Minimum
Maximum
ΔT • hours Diff'l
ΔT
Source
Storage
Minimum
Maximum
ΔT • hours
Diff'l
F
ΔT
Source
Storage
Minimum
Maximum
ΔT • hours
1
HEAT
2
Diff'l
F
Minimum
Maximum
ΔT • hours
1
ΔT
Source
Storage
HEAT
2
Diff'l
F
ΔT
Source
Storage
Minimum
Maximum
ΔT • hours
1
HEAT
2
Diff'l
PRGM
F C
ΔT
Source
Storage
Minimum
Maximum
ΔT • hours
1
2
HEAT
Item
Press and Hold the “Up” and
“Down” buttons for 1 second. The
word “Clr” is displayed and the value
is reset to the current sensor
measurement.
3
Source temperature is the temperature measured by the Source Sensor.
Storage temperature is the temperature measured by the Storage Sensor.
Δ T is the calculated difference between the Source and Storage temperatures.
Maximum Source is the Maximum temperature measured by the Source Sensor since this item was last cleared.
Minimum Source is the Minimum temperature measured by the Source Sensor since this item was last cleared.
Maximum Storage is the Maximum temperature measured by the Storage Sensor since this item was last cleared.
Minimum Storage is the Minimum temperature measured by the Storage Sensor since this item was last cleared.
Energy Transfer (ΔT•hours). This display allows the user to estimate the amount of energy transferred from the source to the storage.
The energy transfer is displayed by alternating between two numbers. When the °C or °F segment is off, the thousands are displayed.
When the °C or °F segment is on, the units are displayed. The energy transfer can be estimated by multiplying the ΔT •hours by the system
flow rate (in US GPM) and by the constant K given in the adjacent table.
Example Energy Transfer = ΔT •hours x System flow x K
ΔT• hrs = 005 (thousands) 225 °F (units) = 5225 °F •hours
System flow = 20 US GPM
Fluid = 20% glycol & 80% water, therefore K = 487
Energy Transfer = 5225 x 20 x 487 = 50,892,000 BTU
Freezing
point
32 ° F
25 ° F
15 ° F
3 ° F
-13 ° F
-35 ° F
K
@ 10 ° F
500
496
487
477
462
439
% Glycol by
weight
0%
10%
20%
30%
40%
50%
K values are calculated
averages for most eth-
ylene glycol solutions
at 50°F (10°C). K in-
creases with higher
temperatures.