- ページ 13

ヒートポンプ Allied 4SHP16のPDF 取付説明書をオンラインで閲覧またはダウンロードできます。Allied 4SHP16 19 ページ。 Single stage heat pump

ページを印刷する

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.

The optimum method for checking the charge is by

weight. However the following methods may be used

to confirm the proper charge:

Cooling Mode

1. Operate unit a minimum of 10 minutes before checking

charge.

Measure liquid service valve pressure by attaching an

accurate gage to service port. Determine saturation

temp. from T/P chart.

Measure liquid line temperature by attaching an

accurate thermistor type or electronic thermometer to

liquid line near outdoor coil.

Calculate subcooling (saturation temp. measured

temp.) and compare with table on back of central box

cover.

Add refrigerant if subcooling is lower than table.

Recover refrigerant if subcooling is high.

If ambient temp is lower than 60°F, check charge in

heating mode or weigh refrigerant according to name

plate data.

Heating Mode

Check charge in heating mode if ambient temp is below

60° F. Indoor temp must be between 65° and 75° F.

Follow steps (1) to (6) above and compare with heating

mode subcooling range on the table on back of central box

cover.

Charge must be rechecked again during the cooling

season.

Cold Weather Application

A cold weather accessory kit may be required for heat

pumps operating at ambient conditions below 25°F.

Supplemental heat should be provided for these conditions.

507919-01F

Operation

Demand Defrost System Description

The demand defrost controller measures differential

temperatures to detect when the system is performing

poorly because of ice build-up on the outdoor coil. The

controller "self-calibrates" when the defrost system starts

and after each system defrost cycle. The defrost control

board components are shown below.

The control monitors ambient temperature, outdoor coil

temperature, and total run time to determine when a

defrost cycle is required. The coil temperature probe is

designed with a spring clip to allow mounting to the outside

coil tubing. The location of the coil sensor is important for

proper defrost operation.

NOTE: The demand defrost board accurately measures

the performance of the system as frost accumulates on the

outdoor coil. This typically will translate into longer running

time between defrost cycles as more frost accumulates on

the outdoor coil before the board initiates defrost cycles.

Diagnostic LEDs

See offset control board diagnostic LED table (Table 3) to

determine operational conditions and diagnose problems.

Figure 6. Control Board

Issue 1846

Page 13 of 19