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Fan Power and Control Plugs -
Torin fan for DC/HC models except
15-95
Domestic Water Flow Sensor
Water Pressure Sensor Type LWCO
TROUBLESHOOTING
DC SERIES BOILERS / WATER HEATERS DC 15-95, DC 15-96, DC 20-125, DC 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 / water heater 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 / water
heater 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 DC boiler / water heater 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 / water heater to reach
maximum firing rate. When the water pressure less than 8psi, the boiler / water
heater will restrict its firing rate. If the pressure is less than 4psi then the boiler /
water heater will not fire at all.
TO TEST THE OPERATION OF THE PRESSURE SENSOR – TYPE LWCO
1.
Turn off the boiler / water heater at the controller by pressing the
The current system pressure will be displayed.
Isolate the space heating circuit and reduce the water pressure. The
2.
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 / water heater and replace sensor, or dislodge any
blocking debris from sensor inlet channel and reinsert.
If the pressure sensor is OK then simply refill the boiler / water heater and
3.
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 / water heater.
2.
Isolate and drain the boiler / water heater.
Remove the Vent Stack.
3.
Disconnect the electrical connection to the sensor.
4.
Carefully remove the clip at the base of the sensor.
5.
Twist the sensor as you are pulling to remove from the socket. There may
6.
be some water leakage at this point. Ensure the water does not spill into the
controller.
Push the new sensor into the socket while twisting slightly. Careful not to
7.
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 / water heater is pressurized.
button.
5-3
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