Troubleshooting guide

Connections
33
Electrical Connections (continued)
Pumps under 4 Amp. can be connected
directly to boiler terminal strip. Pumps
over 4 Amp. must be switched by an
external relay or transformer/relay to
prevent failure of the pump aquastat
See Fig. 16 on previous page.
Pump will not act ivate until boiler water
temperature reaches 116°F. Refer to
pump aquastat shown on wiring
diagrams.
If boiler has been underwater, all
electrical parts must be replaced. All
other parts must be inspected by a
qualified s ervice agency for
acceptability before being used.
Electronic T hermostat Connection
For those installations where an
electronic set-back thermostat is used,
an isolation relay may be necessary.
Any electronic thermostat that normally
requires current from the boiler
transformer will require an is olation
relay. F or example when inst alling a
Honeywell Chronotherm, use an
isolation relay as shown in Fig. 17.
5167 450 v1.4
Honeywell
Chronotherm
electronic set-back
room thermostat
C
F
Transformer relay
Thermostat
connections
120V
120V
24V
H
N
G
Fig. 17