Bard CH5S1, CH4S1, CH3S1 installation instructions Start Up, Low Voltage Connections, Application

LOW VOLTAGE CONNECTIONS

These units use a grounded 24 volt AC low voltage circuit and require at least a 2 stage heating and a 2 stage cooling thermostat.

The “R” terminal is the hot terminal and the “C” terminal is grounded.

“G” terminal is the fan input.

“Y” terminal is the compressor Stage 1 input.

“Y1” terminal is the compressor Stage 2 input.

“B” terminal is the reversing valve input. The reversing valve must be energized for heating mode.

“R” terminal is 24 VAC hot.

“C” terminal is 24 VAC grounded.

“L” terminal is compressor lockout output. This terminal is activated on a high or low pressure trip by the electronic heat pump control. This is a 24 VAC output.

“W2” terminal is second stage heat (if equipped).

“O1” terminal is the ventilation input. This terminal energizes any factory installed ventilation option.

“E” terminal is the emergency heat input. This terminal energizes the emergency heat relay if equipped.

NOTE: For total and proper control using DDC, a total of 7 controlled outputs are required (6 if no ventilation system is installed). For proper system operation under Emergency Heat conditions where the compressor needs to be deactivated, the B-W2-E outputs need to be energized. Removing the Y (compressor) signal alone turns the compressor off, but does not activate the additional circuitry embedded in the heat pump for proper and complete operation.

LOW VOLTAGE CONNECTIONS

FOR DDC CONTROL

Fan Only	Energize G
Cooling Mode 1st Stage	Energize Y, G
Cooling Mode 2nd Stage	Energize Y, Y1, G
Heat Pump Heating 1st Stage	Energize Y, G, B
Heat Pump Heating 2nd Stage	Energize Y, Y1, G, B
3rd Stage Heating	Energize G, W2, Y, B, Y1
w/Heat Pump (if employed)
Ventilation	Energize G, O1
Emergency Heat	Energize B, W2, E, G

TABLE 4

WALL THERMOSTAT

Thermostat	Predominant Features
8403-049	2 stg. cool; 2 stg. heat
	Programmable Electronic
(1F93-380)
	Auto or Manual changeover
8403-052	2 stg. cool; 3 stg. heat
	Programmable Electronic
	Auto or Manual changeover

START UP

These units require R-410A refrigerant & Polyol Ester oil.

APPLICATION:

1.Use separate service and manufacturing equipment to avoid cross contamination of oil and refrigerants.

2.Use recovery equipment rated for R-410A refrigerant.

3.Use manifold gauges rated for R-410A (800 psi/250 psi low).

4.R-410A is a binary blend of HFC-32 and HFC-125.

5.R-410A is nearly azeotropic - similar to R-22 and R-12. Although nearly azeotropic, charge with liquid refrigerant.

6.R-410A operates at 40-70% higher pressure than R-22, and systems designed for R-22 cannot withstand this higher pressure.

7.R-410A has an ozone depletion potential of zero, but must be reclaimed due to its global warming potential.

8.R-410A compressors use Polyol Ester oil.

9.Polyol Ester oil is hygroscopic; it will rapidly absorb moisture and strongly hold this moisture in the oil.

10.A liquid line dryer must be used - even a deep vacuum will not separate moisture from the oil.

11.Limit atmospheric exposure to 15 minutes -

MAXIMUM.

12.If compressor removal is necessary, always plug compressor immediately after removal. Purge with small amount of nitrogen when inserting plugs.

Manual	2100-455A
Page	16 of 25