Starting The Unit - EMI S2HA Installation, Operation And Maintenance Manual

Multi-zone limited range heat pump condensing units

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S2HA & T2HA REFRIGERANT PIPING INSTALLATION SECTION

NOTE: If operating superheat is more

than 5°F above the chart value, add

refrigerant. If below the chart value

remove refrigerant. If below the limit

line, remove refrigerant.

Example (Using the 12,000 Btuh cooling

chart):

1. Suction pressure is 65 psi. which equals

38° F on The R-22 Scale of the Low-

Side Gauge.

2. Suction line temperature taken at the

unit is 70° F. 70° F minus 38° F equals

32° F superheat.

3. Outdoor temperature is 90° F, indoor

temperature is 80° F.

4. Intersection of the indoor-temperature

and outdoor-temperature lines occur on

the 12° F superheat line.

5. Add charge to obtain 12° F superheat.

• Before starting the unit in cool weather,

power the system 24 hours before at-

tempting to start.

• Do a ﬁnal system check using the super-

heat/subcooling method. Record results

on Test Unit Performance Data sheet

(next page).

- Cooling mode superheat is set with a proper

sized piston and charge, using the field

charging charts.

- Heating mode superheat is set with a TXV

and should be 5°F. When charging a system

in heat mode, use the subcool method ﬁeld

charging charts.

Multi-zone Heat Pump Condensing Units

FIELD CHARGING

Instructions:

1. Measure suction pressure and determine

evaporator-refrigerant temperature on

R-22 scale of low-side gauge.

2. Measure suction-line temperature on

suction line of the unit.

3. Measure outdoor and indoor tempera-

tures.

4. Determine from the table what the super-

heat should be for the indoor and outdoor

temperatures. (Example indicates 12° F

superheat.)

5. Adjust charge if needed. Be sure unit is

running at stabilized condition.

NOTE: For installation of the indoor unit

and start-up of the system, please refer

to the appropriate installation manual

for your indoor product to complete the

installation.