Emerson Process Management 1F95-1291 Troubleshooting, Averaging or Weighting Remote Sensors

Averaging or Weighting Remote Sensors

The thermostat will weight or average the temperature of the indoor remote sensor with the local sensor in the thermostat for each program period. The averaging will be active only when the local sensor and the indoor remote sensor are both functional and enabled in the Installer/Configuration menu.

When the thermostat is in the Set Schedule mode, the weight of the indoor sensor will be shown in the current temperature digits of the display. The weight will show as A2 (average and default), H4 (high) or L1 (low). Pressing the and keys at the same time will change the weight for the program period. The weight of the thermostat sensor is fixed.

In normal operation of the thermostat, the current tempera- ture displayed will be the weighted average of the local sensor and the remote sensor using the formula (local sensor weight x local sensor temperature) + (remote sensor weight x remote sensor temperature) / (local sensor weight + remote sensor weight).

Example: Local sensor temperature is 80° and the remote sensor is 70°.

If weight is selected H4, the averaged temperature of 72° will be displayed.

(1 x 80) + (4 x 70) / 5 = 72°

If weight is selected A2, the average temperature of 73° will be displayed.

(1 x 80) + (2 x 70) / 3 = 73.3°

If weight is selected L1, the average temperature of 75° will be displayed.

(1 x 80) + (1 x 70) / 2 = 75°

The example shows that the weight selected would prioritize the overall averaged temperature between the two sensors. The high weight selection caused the remote sensor to have a higher influence in the calculated temperature average than the local sensor and the low weight selection caused the remote sensor to have less influence.

PROGRAMMING

Dual Fuel Temperature Setpoint

When the thermostat is configured for Heat Pump mode and the Dual Fuel feature is selected on, the thermostat can moni- tor the outside temperature using remote sensor F145-1378 or use software logic to determine when to switch to gas heat and shut down the compressor. This eliminates the need for a fossil fuel kit.

The user selectable temperature is called the dual fuel tem- perature setpoint, dF and is set in the Installer/Configuration menu, items 33 or 34. With outdoor remote sensor installed and enabled, the dual fuel temperature setpoint (menu item

33)can be set to a temperature of -5° through 50°. When outdoor remote sensor is not installed, a software logic based dual fuel number (menu item 34) from 01 to 09 can be selected. A higher temperature or dual fuel setting will provide a smaller stage separation between the heat pump and Aux to give more comfort. A lower temperature or number will provide a larger stage separation for more economy.

After the dual fuel temperature setpoint is set andis pressed, a delay, Cd, can be set for compressor shutdown after the auxiliary stage is energized. This delay can be set from 0 seconds to 99 seconds to minimize the time that the system may blow cooler air until the alternate source of heat comes on. Default setting for delay is 60. When setting the delay, if the or keys are held depressed, the setpoint will increase or decrease at the rate of one degree every half second for the first three seconds and double the speed after three seconds.

Blower Balance Point for Heating

Requires DHM connection from thermostat to heat pump system. Air to air heat pumps use a fast fan speed to circu- late warm air for first stage heating. As outdoor temperatures drop, the heat pump produces less heat and a high fan speed makes the air from the ducts feel cooler. Blower Balance Point allows you to select an outdoor temperature to slow the fan speed so the air from the duct feels warmer. Select an out- door temperature where the air from the ducts starts to feel cool (Installer Configuration Menu item 37). When the outdoor temperature drops to the selected temperature, the thermo- stat will slow the fan speed so the outlet air feels warmer.

TROUBLESHOOTING

Comfort Alert Codes

The Comfort Alert diagnostics product monitors the air con- ditioning outdoor systems with single phase Copeland Scroll compressors. Abnormal system and electrical conditions are indicated by flashing ALERT codes on the yellow LED on the Comfort Alert module. The flash codes are transmitted to the thermostat by the Comfort Alert Thermostat interface module. The Comfort Alert compatible thermostat displays “Call For Service” that flashes at the same rate as the yellow LED on the Comfort Alert module.

		Comfort Alert Codes
1	Flash		Long run time
2	Flashs		System pressure trip
3	Flashs		Short cycling
4	Flashs		Locked rotor
5	Flashs		Open circuit
6	Flashs		Open start circuit
7	Flashs		Open run circuit
8	Flashs		Welded Contactor
9	Flashs		Low voltage

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