INSTALLATION AND OPERATION INSTRUCTIONS
1-36
SFC COMBI BOILERS SFC-99, SFC-125
External probe type low water cutoff device
You can link a field-supplied, external safety device to the unit by connecting the
safety device in series with the unit’s 120V main power supply.
If the unit is being used only as a direct domestic hot water unit an external low
water cut-off device is not required. However, if required, we recommend using
an electronic probe style device:
•
Install the probe type low water cut-off device with a Tee connection at a level
above the top of the unit.
•
Wire the probe type low water cut-off device in series with the 120Vac power
supply, so that when the device trips on a low water condition the power
supply to the unit is interrupted.
Figure 37: External Probe Type Low Water Cutoff Device
1.9.2 Power Quality and Electrical Protection
In areas of unreliable power, appropriate surge protectors and / or power
conditioning equipment should be installed to protect the unit.
1.9.3 Zone Valve and Zone Pump Connections
Zoning can be accomplished with either zone pumps or zone valves. If zoning by
multiple pumps, we recommend using an external pump module.
Zone valve end switches can be wired together in parallel, and connected to X13
terminals 1 and 2. Do not apply power to the X13 terminal strip. Alternatively, you
can connect the zone valves and thermostats to a zoning panel control system
(available from your local heating wholesaler).
You can connect zone pumps to the unit with a zone pump control, available from
your local heating wholesaler.
