5-9
TROUBLESHOOTING
DC SERIES BOILERS / WATER HEATERS
DC 15-95, DC 15-96, DC 20-125, DC 33-160
5.4.5 No Space Heating
POSSIBLE CAUSES
SOLUTION
Room thermostat (end switches or zone
controller) / Outdoor sensor faulty.
•
Room thermostat must be a DRY CONTACT style thermostat
•
Check the wiring.
•
Check and/or Replace the thermostat (end switches or zone controller).
•
Replace the outdoor sensor.
No voltage (24V DC).
•
Check the wiring against the diagram.
•
Check the connector terminals X4.6 and X4.7 for 24V DC with thermostat
wires disconnected.
•
Check the Fuse.
•
Replace the controller.
Internal Pump not running.
•
Check the power supply.
•
Check connector X2.7 and X2.8 for 120VAC while the pump should be
running.
•
Replace faulty pump if 120VAC is present when the pump should be
running.
•
Replace the controller if 120V is not present when the pump should be
running.
Burner not firing on space heating: sensor S1 or
S2 faulty.
Replace sensor S1 or S2. See fault code.
Burner does not ignite.
See 5.4.1 Burner Does Not Ignite
5.4.6 Indoor Temperature Does Not Reach Desired Temperature
POSSIBLE CAUSES
SOLUTION
Room thermostat setting incorrect.
Check the setting and if necessary adjust: Set heat anticipator to 0.1A.
Thermostat must be a DRY CONTACT style thermostat
Water temperature is too low.
Increase the space heating water temperature. See Table of Programmable
Parameters in DC / HC Controller Manual. Check outdoor sensor and wiring
for short-circuit.
Water temperatures are set incorrectly
Target water temperature is set higher than the maximum water
temperature.
Pump not running correctly. Pump setting is too
low (variable speed pumps only).
Increase pump setting, or replace the pump.
No circulation in the heating system.
Ensure the zone valves are open and there are no air blockages.
No heat transfer as a result of lime scale or
fouling in the heat exchanger.
De-scale or flush the heat exchanger on the space heating side.
5.4.7 No Hot Water (DHW)
POSSIBLE CAUSES
SOLUTION
Flow sensor not functioning.
•
DHW flow < 2.0 l/min – .5 GPM.
•
Clean or replace the flow sensor.
No voltage at the flow sensor (5V DC).
Check the wiring according to the diagram.
Burner not firing on DHW: S3 faulty.
Replace S3.
Burner does not ignite.
See 5.4.1 Burner Does Not Ignite
