T775 SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
19
63-7147—05
IMPORTANT
After the desired value is selected, be sure to press
the
or
or
HOME
button in order to save that
value in the controller’s memory.
Fig. 20. Boiler control staging behavior (when effective
setpoint = 200° F).
Fig. 21. Reset curve with optional setback offset.
Wiring
All output relays should have a common power wiring source,
which may or may not be the same as the T775 power wiring.
NOTE: The Multi-Stage Boiler Control (Reset) application
continues on the next page.
Multi-Stage Boiler Control (Reset)
(continued)
Fig. 22. T775P wiring — multi-stage boiler control
with reset.
THROTTLING RANGE (18°F)
-33%
0%
33%
67%
1
206°F
200°F
194°F
188°F
M28043
STAGE 2 ON
STAGE 3 ON
STAGE 1 ON
STAGES
HYST.
STAGE 1
STAGE 2
STAGE 3
1
DISCHARGE WATER TEMPERATURE
STAGE ENERGIZES
STAGE DE-ENERGIZES
SENSOR B
SP MAX A1
(BOILER MAX)
SP MIN A2
(BOILER MIN)
200
140
10
SETBACK
OFFSET
-10°F
(OPTIONAL)
190
20
30
40
50
60
70
°F
80
150
160
170
210
220
180
°F
RESET B1
(OUTSD MIN)
RESET B2
(OUTSD MAX)
S
E
N
S
O
R
A
M24869
T
T
M24868
T
T
L1
(HOT)
L2
SENSOR A
(DISCHARGE WATER)
C
NO
NC
C
NO
NC
C
NC
NO
C
NC
NO
T
T
RELAY
1
C
+
RELAY
4
RELAY
3
RELAY
2
T775P
BOILER #1
SENSOR C
(RETURN WATER)
SENSOR B (OUTSIDE AIR)
L1
(HOT)
L2
120
COM
240
1
2
120 VAC
POWER WITH 24 VAC OR 120/240 VAC AT THE APPROPRIATE TERMINAL BLOCK.
24 VAC POWER TERMINAL BLOCK.
1
2
BOILER #2
BOILER #3
PUMP
Summary of Contents for T775 Series 2000
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