5-3
TROUBLESHOOTING
HC SERIES BOILERS
HC 13-50, HC 23-84, HC 29-106, HC 20-125, HC 33-160
5.2.2 Fan/Blower
Operating power is provided by means of a separate 120 VAC connector at the
upper right side of the fan (white/black/green). Control of the fan is provided via a
four lead connector at the bottom of the fan.
5.2.3 Thermostat Connections
The boiler controller is designed to heat a single space heating load. The load can
consist of a single zone or several zones. In either case the ‘Call for Heat’ must be
from a device providing a DRY CONTACT and connected to X4.6 and X4.7. The use
of power robbing thermostats directly will cause the boiler to operate erratically. If a
power robbing thermostat is to be used it will have to be isolated through a relay.
5.2.4 Water Pressure Sensor-Type Low Water Cut Off
(LWCO)
The HC boiler is equipped with a pressure sensor which serves as a low-water
cut-off. The water pressure is displayed in the main display when the pressure is
low. For example a system water pressure of 4.6psi would be displayed as 4.6P.
If the pressure is too low the controller will flash an error message in the main
display by toggling between the actual pressure and LO. Simply increase the
system pressure to correct this error. The water pressure in the heating system
must be higher than 8psi for the boiler to reach maximum firing rate. When the
water pressure less than 8psi, the boiler will restrict its firing rate. If the pressure
is less than 4psi then the boiler will not fire at all.
TO TEST THE OPERATION OF THE PRESSURE SENSOR – TYPE LWCO
1.
Turn off the boiler at the controller by pressing the
button. The current
system pressure will be displayed.
2.
Isolate the space heating circuit and reduce the water pressure. The
displayed water pressure should drop as the system water is being removed.
If the pressure is remaining steady then the pressure sensor may be blocked
or faulty. If so, drain boiler and replace sensor, or dislodge any blocking
debris from sensor inlet channel and reinsert.
3.
If the pressure sensor is OK then simply refill the boiler and open the closed
valves. Ensure the system pressure is adequate for the heating system.
PRESSURE SENSOR LWCO REPLACEMENT
1.
Turn off the power to the boiler.
2.
Isolate and drain the boiler.
3.
Remove the Vent Stack.
4.
Disconnect the electrical connection to the sensor.
5.
Carefully remove the clip at the base of the sensor.
6.
Twist the sensor as you are pulling to remove from the socket. There may
be some water leakage at this point. Ensure the water does not spill into the
controller.
7.
Push the new sensor into the socket while twisting slightly. Careful not to
damage the O-ring.
8.
Reinstall the clip at the base of the sensor to ensure the sensor does not
come out when the boiler is pressurized.
9.
Connect the electrical connector to the sensor.
10.
Reinstall the vent stack.
Fan Power and Control Plugs
Water Pressure Sensor Type LWCO
