Carrier Heat Pump Start-Up Instructions for Models 25HCB3 and 25HCC5

Install Electrical Accessories

Refer to the individual instructions packaged with kits or accessories when installing.

Start-Up

!CAUTION

PERSONAL INJURY HAZARD

Failure to follow this caution may result in personal injury.

Wear safety glasses, protective clothing, and gloves when handling refrigerant and observe the following:

S Front seating service valves are equipped with Schrader valves.

!CAUTION

ENVIRONMENTAL HAZARD

Failure to follow this caution may result in environmental damage.

Federal regulations require that you do not vent refrigerant to the atmosphere. Recover during system repair or final unit disposal.

!CAUTION

UNIT OPERATION AND SAFETY HAZARD

Failure to follow this caution may result in personal injury, equipment damage or improper operation.

S Do not overcharge system with refrigerant.

S Do not operate unit in a vacuum or at negative pressure. S Do not disable low pressure switch in scroll compressor

applications.

S Compressor dome temperatures may be hot.

Follow these steps to properly start up system:

1.After system is evacuated, fully open liquid and vapor service valves.

2.Unit is shipped with valve stem(s) front seated (closed) and caps installed. Replace stem caps after system is opened to refrigerant flow (back seated). Replace caps finger-tight and tighten with wrench an additional 1/12 turn.

3.Close electrical disconnects to energize system.

4.Set room thermostat at desired temperature. Be sure set point is below indoor ambient temperature.

5.Set room thermostat to HEAT or COOL and fan control to ON or AUTO mode, as desired. Operate unit for 15 minutes. Check system refrigerant charge.

		TYPICAL		HEAT
HP THERMOSTAT		FAN COIL		PUMP
24 VAC HOT	R	R		R
24 VAC COM	C	C		C
24 VAC COM	C	C
HEAT STAGE 2	W2	W2	*	W2
		E *		W2
COOL/HEAT	Y	E *
STAGE 1	Y	W3 *		Y
STAGE 1				Y

INDOOR FAN	G	G
		G
RVS COOLING	O			O
EMERGENCY	E	* IF AVAILABLE
HEAT		* IF AVAILABLE

LEGEND

24-V FACTORY WIRING

24-V FIELD WIRING

FIELD SPLICE CONNECTION

ODT

OUTDOOR THERMOSTAT

EHR EMERGENCY HEAT RELAY

SHR SUPPLEMENTAL HEAT RELAY

A02325 / A97413

Fig. 8 - Generic Wiring Diagrams

(See Thermostat Installation Instructions

for specific unit combinations)

Sequence of Operation

NOTE: Defrost control board is equipped with 5 minute lockout timer that is initiated upon any interruption of power.

Turn on power to indoor and outdoor units. Transformer is energized.

Cooling

On a call for cooling, thermostat makes circuits R-O, R-Y, and R-G. Circuit R-O energizes reversing valve, switching it to cooling position. Circuit R-Y sends low voltage through the safeties and energizes the T1 terminal on the circuit board. If the compressor has been off for 5 minutes, or power has not been cycled for 5 minutes, the OF2 relay and T2 terminal will energize. This will close the contactor, and start the outdoor fan motor and compressor.

When the cycle is complete, R-Y is turned off, stopping the compressor and outdoor fan. The 5 minute time guard begins counting. Compressor will not come on again until this delay expires. In the event of a power interruption, the time guard will not allow another cycle for 5 minutes.

NOTE: If the indoor blower off delay is enabled, it will run up to an additional 90 seconds to increase system efficiency.

Heating

On a call for heating, thermostat makes circuits R-Y and R-G. Circuit R-Y sends low voltage through the safeties and energizes the T1 terminal on the circuit board. T1 energizes the defrost logic circuit. If the compressor has been off for 5 minutes, or power has not been cycled for 5 minutes, the OF2 relay and T2 terminal will energize. This will close the contactor, start the outdoor fan motor and compressor.

When the cycle is complete, R-Y is turned off , stopping the compressor and outdoor fan. The 5 minute time guard begins counting. Compressor will not come on again until this time delay expires. In the event of a power interruption, the time guard will not allow another cycle for 5 minutes.

25HCB3 / 25HCC5

25HCC5, 25HCB3 specifications

The Carrier 25HCB3 and 25HCC5 are technologically advanced HVAC systems designed to meet the needs of modern residential and commercial spaces. These models stand out for their efficiency, reliability, and eco-friendliness, making them excellent choices for anyone looking to enhance indoor comfort while minimizing energy consumption.

One of the main features of the Carrier 25HCB3 and 25HCC5 is their exceptional SEER (Seasonal Energy Efficiency Ratio) rating, which signifies a higher cooling efficiency compared to traditional air conditioning systems. These units leverage Carrier's innovative design to deliver cooling and heating solutions that are tailored to various climate conditions, ensuring optimal performance year-round.

Both models utilize a variable-speed compressor, which allows them to adjust their cooling output based on the specific needs of the space. This technology not only enhances comfort by providing consistent temperatures but also reduces energy consumption, contributing to lower utility bills. The variable-speed operation is particularly beneficial during transitional seasons, where less intensive cooling is required.

In addition to their variable-speed capabilities, the 25HCB3 and 25HCC5 offer advanced filtration systems designed to improve indoor air quality. These systems can effectively capture airborne allergens, dust, and particulates, creating a healthier living environment. Moreover, users can opt for enhanced filtration options, which utilize HEPA filters for even greater allergen removal.

Another key characteristic of these models is their quiet operation. The Carrier 25HCB3 and 25HCC5 are engineered with sound-dampening features that minimize operational noise. This is especially advantageous for residential applications where tranquility is valued.

Durability is also a hallmark of Carrier systems. The 25HCB3 and 25HCC5 are built with robust materials and advanced protective mechanisms, ensuring that they can withstand the rigors of various weather conditions and provide reliable service for years to come.

In terms of smart technology, these models are compatible with Carrier's smart thermostat solutions, allowing users to monitor and control their HVAC systems remotely. This connectivity enhances user convenience and promotes energy efficiency by enabling users to adjust settings based on their schedules and needs.

Overall, the Carrier 25HCB3 and 25HCC5 represent a significant advancement in HVAC technology, combining high efficiency, advanced features, and user-friendly operation. Whether for residential or commercial use, these systems provide a comprehensive solution for anyone seeking reliable and effective climate control.