Ducane (HVAC) 2HP13 Emergency Heat heating heat pump, Start-Up Procedure, Adjusting Charge

Heat Pump Application with Electric Heat

Emergency Heat (heating heat pump)

If selector switch on thermostat is set to the emergency heat position, the heat pump will be locked out of the heating circuit, and all heating will be electric heat ( if applicable). A jumper should be placed between W and E on the thermostat so that the electric heat control will transfer to the first stage heat on the thermostat. This will allow the indoor blower to cycle on and off with the electric heat when the fan switch is in the AUTO position.

* Add Jumper on Subbase (Optional)

Start-Up Procedure

1.Check to ensure:

!Service valve and gage port caps are installed and tightened.

!Voltage supply at unit agrees with nameplate rating.

!Field wiring connections are tight and factory wiring has not been disturbed and are tight.

!Indoor fan motor is on correct speed tap.

2.Set thermostat selector switch to OFF and fan control switch to "Auto" is so equipped.

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 the system switch of the thermostat on COOL (or HEAT if applicable) and fan switch for continuous operation (ON) or AUTO, as desired. There will be a 5 minute short cycle compressor delay on startup. Operate unit for 15-20 minutes, then check the system refrigerant charge.

6.Adjust refrigerant charge per "Adjusting Charge" section.

Adjusting Charge

Factory charge is shown on the rating label located on the access panel.

All split system heat pumps are factory charged for 15 feet of connecting line set and matched indoor fan coil. Nameplate refrigerant charge should initially be adjusted for line set lengths other than 15 feet. For line sets shorter than 15 feet in length, remove charge. For line sets longer than 15 feet, add charge. Oil charge is sufficient for all line lengths.

Refrigeration Charge Adjustment

Liquid Line Diameter	Oz. Per Linear Foot *
3/8"	.6

*Factory charge for series is for 15' (ft.) line sets and matched fan coil.

Before final adjustment is made to the refrigerant charge, it is imperative that proper indoor airflow be established. Airflow will be higher across a dry coil versus a wet coil. Blower charts are calculated with a dry or wet coil basis. Recommended airflow is 350-450 CFM per ton (12,000 Btuh) through a wet coil. Refer to indoor unit instructions for methods of determining air flow and blower performance.

Cooling Cycle Charge Adjustment

The optimum method for checking the charge is by weight. However the following methods may be used to confirm the proper charge:

Units with Indoor Pistons

Units installed with indoor pistons require charging with the superheat method.

The following procedure is valid when indoor airflow is within ± 20% of its rated CFM.

1.Operate unit a minimum of 10 minutes before checking charge.

2.Measure suction pressure by attaching a gage to suction valve service port. Do not use compressor suction port. Determine saturation temp from T/P chart.

3.Measure suction temperature by attaching an accurate thermistor type or electronic thermometer to suction line at service valve.

4.Calculate superheat (measured temp. — saturation temp.).

5.Measure outdoor air dry-bulb temperature with thermometer.

6.Measure indoor air (entering indoor coil) wet-bulb temperature with a sling psychrometer.

7.Compare superheat reading at service valve with the chart located on control box cover.

8.If unit has a higher suction line temperature than charted temperature, add refrigerant until charted temperature is reached.

9.If unit has a lower suction line temperature than charted temperature, reclaim refrigerant until charted temperature is reached.

100402-07 Issue 0733 Page 6 of 18