Potterton NXR3 Installation, Operation And Maintenance Manual page 30

SECTION 6
PAGE 28
Wiring Diagram – Notes & Legend
Important: Maximum current rating at each terminal is 2A. Loads greater than 2A require isolating relays or
contactors, this particularly applies to pumps and fans.
Legend:
STB
ZSB
ZT
F1
VSC
MST
TR
TR1
TR2
ZP
L
N
ZG
BRU
H
External Interlocks:
DG
UV
XY
Relays
Fig. 20 - Pump Overrun Using Changeover Pipe Thermostat
Pump
POTTERTON COMMERCIAL PRODUCTS DIVISION
INSTALLATION, OPERATION & MAINTENANCE MANUAL
- Overheat thermostat
- Burner reset
- Burner test switch
- Fuse
- Overheat indicator light
- Mains indicator light
- Safety mode thermostat
st
- 1 stage regulation thermostat
nd
- 2 stage regulation thermostat
- Pump switch (not used)
- Live
- Neutral
- On/Off switch
- Burner connections
- Hours run counters
- External interlock
- Safety interlock
- Safety interlock
- Overheat & Fault
C
Pipe Thermostat
Set <55° C
L1
Incoming
L2
Supply
L3
N
NO
NC
Auxiliary Contact on
Boiler time control, etc
NXR3
L