Option 03 — fahrenheit/centigrade selection, Option 04 — g (fan) on with w (heat) selection, Option 13 — room temperature offset adjust- ment – Carrier TB-NHP User Manual

Page 3: Step 4 — thermostat operation, Step 5 — check thermostat operation

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Option 03 — Fahrenheit/Centigrade Selection

This selection operates the thermostat in either Fahrenheit or
Centigrade. Factory default is F.
Available Selection:
Use UP and DOWN buttons to change between F and C.

Option 04 — G (fan) ON with W (Heat) Selection

This selection determines whether G (fan) output is to be ON or
OFF when W (furnace or strip heat) output is ON. Most furnaces

and fan coils manage their own blowers and do not require a

separate G signal. For these applications, select OFF. Some
auxiliary heaters require a separate G signal from the thermostat to

turn on the blower. In this case, select ON. Factory default is OF
(off).
Available Selection:
Use UP and DOWN buttons to change between ON and OFF.

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 Adjust-

ment

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
A 5--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 oper-

ation. 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 im-

mediately.

3. For HP thermostats only, press H/C button until EMHT

(emergency heat) appears. Press UP and FAN buttons sim-

ultaneously 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 simultan-
eously to defeat timers. Cooling system should begin to op-

erate immediately.

Table 1 shows the thermostat outputs for each available stage of

heating or cooling. It may be useful in checkout or
troubleshooting.

Table 1 – Outputs

EQUIPMENT

CONFIGURATION

OPTION #1

THERMOSTAT

FACTORY

CONFIGURATION

COOL

STAGE 1

HEAT

STAGE 1

HEAT

STAGE 2

EM HEAT

AC, PC

AC, HP

Y, G

W

--- ---

--- ---

HP, PH

RVS = C

HP

Y, G, O/B

Y, G

Y, G, W

W

HP, PH

RVS = H

HP

Y, G

Y, G, O/B

Y, G, W, O/B

W

TB

--

NAC

/TB

--

NH

P

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