Weil-McLain BCP-3 manual Troubleshooting

BCP-3 Installation and Operation Manual

Troubleshooting

No Display or LED Lights

Check the power to the BCP-3. The BCP-3 requires 120VAC power to the Black wires or 24VAC to the right-most terminals. Turn the power off and back on to restore the display. If unsuccessful, make sure that the control's Display Cover is securely mounted to the Base.

System or Outdoor Reads OPEN or SHORT

If the sensor reads Open, short the sensor input terminals. The display should read SHORT. If it doesn’t, the BCP-3 may be damaged.

If the sensor reads Short, remove the wires from the input terminals. The display should read OPEN. If it doesn’t, the BCP-3 may be damaged.

System or Outdoor Sensor Reads an Incorrect Temperature

Remove the sensor wires from the input terminals. The display should change to read OPEN. If it doesn’t, the BCP-3 may be damaged. Take an ohm reading across the detached sensor wires. The ohm reading should correspond to the Temperature Sensor Chart. If the difference is within 5°F adjust the sensor Trim. Otherwise, the sensor may be damaged.

No Heat - All LEDs are OFF

Check the outdoor temperature and the Outdoor Cutoff readings. If the outdoor temperature is above the Outdoor Cutoff, the BCP-3 will not give heat. If the display shows TSTAT OPEN then, check the EXT terminals. If the EXT terminals are not jumped together, the BCP-3 will not give heat.

No Heat - All LEDs are ON

First, make sure that the system pump is running. Remove any connections to the Yellow wires for the Heating System Pump. Test for continuity across the pair of Yellow wires. If the wires are continuous, the BCP-3 is calling for the Heating System Pump to run and the problem is not with the BCP-3. Check the power source to the pump and the pump to determine why it is not circulating.

Second, check the boiler operation and safety control status.

No Heat - System Pump LED ON

Check that the displayed System water temperature is below the Target water temperature minus the Differential. If not, wait until the System temperature falls, and then the stage LED should come on and the boiler should fire. Otherwise, remove all connections from the Blue pair of wires. Check for continuity across the pair of Blue wires using a meter. If the wires are continuous, the BCP-3 is calling for the boiler to run. Check the boiler to determine why it is not firing.

No Heat - Boiler LED ON

Temperature Sensor Chart

The BCP-3 is registering a call for DHW. If the DHW Priority is set to a value other than NO, the Heating System Pump will not run during the priority period of a DHW call. Generally, the DHW will be satisfied before a drop in ambient temperature is noticeable. If the DHW load is large or the boiler can satisfy both loads, change the Priority setting to NO, this will allow the Heating System Pump to circulate hot water to the building while the DHW tank is being satisfied.

TEMPERATURE	Value
(in Degrees °F)	(in Ohms)
-30	117720
-20	82823
-10	59076
0	42683
10	31215
20	23089
25	19939
30	17264
35	14985
40	13040
45	11374
50	9944
55	8714
60	7653
70	5941
80	4649
90	3667

TEMPERATURE	Value
(in Degrees °F)	(in Ohms)
100	2914
110	2332
120	1879
130	1524
140	1243
150	1021
160	842
170	699
180	583
190	489
200	412
210	349
220	297
230	253
240	217
250	187

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