User Manual
2/4 23.03.2005 CE1G2725en Building Technologies / HVAC Products
Connection diagrams
RRV851 - Terminals
B1 Signal input (ext. sensor NTC) D_GND Digital ground Q… Digital outputs, AC24..230V, 6(4) A
M Signal ground HB+, HB- Communication bus Y... Digital outputs, AC24..230V, 3(1) A
D1,D2 Digital inputs L, N AC 230V supply
RRV851 - Typical connection
B
1
M
D
1
D
_
G
N
D
D1
D
2
D2
H
B
+
H
B
-
H
B
+
H
B
-
L
N
Q
7
4
Q
8
4
Q
9
4
Q
7
1
1
2
3
F1
1
Y
1
1
Y
1
2
Y
1
4
Y
2
1
Y
2
2
Y
2
4
Y
3
4
Y
3
1
Y1
N1 N2
AC 230V
L
N
T
X
+
T
X
-
4
8
5
g
n
d
RS485
Y2
B1
F2
Y3
`
*the RS485 connections are only suit-
able for downloading manufacturer
specific parameter sets.
N1 RRV851 controller D2 Faults or emergency heat F2 Single speed fan
N2 QAX850 master room unit Y1 Cooling output RV Reversing valve
B1 External temperature sensor (optional) or Y2 Heating output CR1 Compressor relay stage 1
pipe changeover sensor, appl. A8 Y3 Auxiliary heat, emergency heat or 2
nd
stage cooling CR2 Compressor relay stage 2
D1 Remote activation of comfort mode F1 Three speed fan Y4 Valve actuator, AC24/ 230V
Output connection for 2-p control, appl. A8 Output connection for optional 3-p control, appl. A1, A2 & A8
Y
1
1
Y
1
2
Y
1
4
Y
1
Y
2
Y4
Y
2
1
Y
2
2
Y
2
4
AC 24
/230V
N1
Y
1
1
Y
1
2
Y
1
4
Y
1
Y
2
Y4
Y
2
1
Y
2
2
Y
2
4
AC 24
/230V
N1
Output connection for heat pumps, appl. A5
(for single compressor heat pumps, CR2 is not connected)
Y
1
1
Y
1
2
Y
1
4
Y
2
1
Y
2
2
Y
2
4
N1
Y
3
4
Y
3
1
CR2
CR1
RV
AC 24
/230V
Note!
Contact your local Siemens Building Technologies representatives fo
r
application specific wiring diagrams and information