Carrier TB-NHP Option 10 O reversing valve On with Heat or Cool Selection, Thermostat Operation

Option 10 — O (reversing valve) On with Heat or Cool Selection

This selection is only available on heat pump model thermostats. This selection determines whether the reversing valve is energized in the heating or cooling mode. Factory default is C.

Available Selection:

Use UP and DOWN buttons to change between H and C.

Option 13 — Room Temperature Offset Adjustment

This option allows calibration (or deliberate miscalibration) of the room temperature sensor. There are various reasons why homeowners may want to have displayed temperature adjusted to a higher or lower value. The selected number is the number of degrees, plus or minus, which will be added to actual temperature.

The numbers can range between -5 and +5. Factory default is 0.

Available Selection:

Use UP and DOWN buttons to now move between -5 and +5 in increments of 1.

Step 4 — Thermostat Operation

Temperature Display

Thermostat will display room temperature until UP or DOWN button is pressed. The word SET appears when these buttons are pressed and the current setpoint is displayed. If no buttons are pressed for 5 sec, the display will change back to show room temperature.

Timeguard Timer

A5-minute timeguard is built into the thermostat immediately upon power up, and any time the compressor turns off. The compressor will not turn on until the timeguard has expired. The timeguard affects only compressor operation. Pressing UP and FAN buttons simultaneously will override the timeguard for 1 cycle. With PH or PC selected under Option 01, this timer is defeated.

Cycle Timer

In normal heating and cooling operation the thermostat will not allow more than 4 equipment cycles per hour (or 1 cycle every 15 minutes). Both the Y and W outputs have a 15-minute timer that starts counting down when the output is turned on, (e.g., if Y output is turned on for 9 minutes and then satisfies, it cannot turn back on for another 6 minutes regardless of demand). However, pressing UP and FAN buttons simultaneously or changing the setpoint will override the timer for 1 cycle.

Minimum on Timer

Once the equipment has turned on, it will remain on for a minimum of 3 minutes regardless of demand. However, the

equipment can turn off in less than 3 minutes if a change in setpoint or a change in mode occurs.

Staging Timer

If the thermostat is a heat pump model, it has 2-stage heat capability. With HP operation, there is a 15-minute delay between the first and second stages of heat. The Y output will energize first, then 15 minutes later, W is allowed to come on if the thermostat determines it is not satisfying the demand.

However, if the heating demand is greater than 5_F, there will be only a 30 second delay before bringing on W.

Auxiliary Heat Indicator

A green LED indicates the use of auxiliary heat or emergency heat.

Error Messages

“--” (two dashes) will be displayed if the thermostat cannot properly read room temperature. If “--” appears, replace thermostat.

E4 will be displayed if the thermostat has an internal memory failure. If E4 appears, replace thermostat.

Step 5 — Check Thermostat Operation

Fan Operation

1.Press FAN button. This will start continuous fan operation. FAN annunciator will turn on.

2.Press FAN button again. This will stop continuous fan operation. FAN annunciator will turn off.

Heating Operation

1.Press H/C button until HEAT is displayed.

2.Press UP button until LCD readout reads 3_F above room temperature. Press UP and FAN buttons simultaneously to defeat timers. Heating system should begin to operate immediately.

3.For HP thermostats only, press H/C button until EMHT (emergency heat) appears. Press UP and FAN buttons simultaneously to defeat timers. Emergency heating (W is ON, Y is OFF) should begin immediately.

Cooling Operation

1.Press H/C button until COOL is displayed.

2.Press DOWN button until LCD readout reads 3_F below room temperature. Press UP and FAN buttons simultaneously to defeat timers. Cooling system should begin to operate immediately.

Table 1 shows the thermostat outputs for each available stage of heating or cooling. It may be useful in checkout or troubleshooting.

TB-- NAC / TB-- NHP

Table 1 – Outputs

EQUIPMENT	THERMOSTAT	COOL	HEAT	HEAT
CONFIGURATION	FACTORY				EM HEAT
		STAGE 1	STAGE 1	STAGE 2
OPTION #1	CONFIGURATION
AC, PC	AC, HP	Y, G	W	--- ---	--- ---
HP, PH	HP	Y, G, O/B	Y, G	Y, G, W	W
RVS = C
HP, PH	HP	Y, G	Y, G, O/B	Y, G, W, O/B	W
RVS = H

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