Carrier 50VS specifications Wire Field Control Connections, Install Hose Kit, Maximum RUN Unit to

Step 7 — Wire Field Control Connections

STANDARD 24-V THERMOSTAT CONNECTIONS — The thermostat should be wired directly to the microprocessor board terminals labeled P1 to the corresponding terminals (R,C,Y1,Y2,O,G).

Installation of Optional Wall-Mounted Thermostat — The unit can be controlled with a remote 24-volt surface mounted thermostat such as the Honeywell TH5320U1001 or TH6320U1000 series thermostat. Refer to instructions pro- vided with remote thermostat for wiring instructions using 2 stages of heating and 2 stages of cooling for a heat pump system.

Below are typical thermostat connections and color codes. Rc Power (Red)

RR+Rc joined by factory jumper wire (Red) Y Compressor Contactor (Stage 1) (Yellow) Y2 Compressor Contactor (Stage 2) (Blue)

C 24-vac Common (White) O Reversing Valve (Orange) G Fan Relay (Green)

NOTE: The terminal block on the microprocessor board is removable for ease of thermostat wiring installation.

Low-voltage wiring between the unit and the wall thermo- stat must comply with all applicable electrical codes (i.e., NEC and local codes), and be completed before the unit is installed. Use of six-wire, color-coded, low-voltage cable is recommended.

Table 7 lists recommended wire sizes and lengths to install the thermostat. The total resistance of low voltage wiring must not exceed 1 ohm. Any resistance in excess of 1 ohm may cause the control to malfunction because of high voltage drop.

Table 7 — Recommended Wire Gage — Low

Voltage Thermostat

WIRE SIZE (gage)	MAXIMUM RUN (UNIT TO
	THERMOSTAT) (ft)
22	30
20	50
18	75
16	125
14	200

Step 8 — Clean and Flush System — Cleaning and flushing the unit is the most important step to ensure proper start-up and continued efficient operation of the system. Follow the instructions below to properly clean and flush the system.

1.Verify that electrical power to the unit is off.

2.Verify that supply and return riser service valves are closed at each unit.

3.Fill the system with water, leaving the air vents open. Bleed all air from the system but do not allow the system to overflow. Check the system for leaks and make any re- quired repairs.

4.Adjust the water and air level in the expansion tank.

5.With strainers in place, start the pumps. Systematically check each vent to ensure that all of the air is bled from the system.

6.Verify that make-up water is available and adjusted to properly replace any space remaining when all air is purged. Check the system for leaks and make any addi- tional repairs if needed.

7.Set the boiler to raise the loop temperature to approxi- mately 85 F. Open the drain at the lowest point in the system. Verify that make-up water replacement rate

equals rate of bleed. Continue to bleed the system until the water appears clean or for at least three hours which- ever is longer.

8.Completely drain the system. Flush risers as follows:

1.Close shut-off valves at each unit on the riser except the shut-off valve on the top floor.

2.Flush solution through supply riser.

NOTE: The solution passes through the top floor connec- tion down the return riser.

3.When the building has more than 10 floors, connect the supply and return run outs on the top two floors to divide the water flow and reduce pressure drop at the pump.

4.Repeat flushing procedure for each set of risers in the building.

5.Refill the system and add in a proportion of trisodium phosphate approximately one pound per 150 gallons of water. Reset the boiler to raise the loop temperature to about 100 F.

6.Circulate the solution for between 8 and 24 hours. At the end of this period, shut off the circulating pump and drain the solution. Repeat system cleaning if needed.

7.Open the supply and return riser service valves at each unit. Refill the system and bleed off all air.

8.Test the system pH with litmus paper. The system water should have a pH of 6 to 8.5. Add chemicals as appropri- ate to maintain pH levels.

9.When the cleaning process is complete, remove the short- circuited hoses. Reconnect the hoses to the proper supply, and return the connections to each of the units. Refill the system and bleed off all air.

NOTE: DO NOT use “Stop Leak” or similar chemical agent in this system. Addition of chemicals of this type to the loop water will foul the heat exchanger and inhibit unit operation.

Step 9 — Install Hose Kit

1.Refer to Fig. 11 for an illustration of a typical supply/ return hose kit assembly.

2.Pipe joint compound or Teflon tape is not necessary when using factory-supplied hose kits.

NOTE: When anti-freeze is used, ensure that it is compat- ible with Teflon tape and pipe joint compound that may have been applied to other pipe fittings in the system.

3.Attach the flex hoses. Unpack and examine hose kit. Re- move all shipping and/or packing material such as rubber bands, plastic caps, and styrofoam. Hose kit should con- tain 2 hoses, one balancing valve with shutoff, one shut- off, and 2 hose adaptors.

4.Locate the valves inside the unit cabinet marked WATER IN and WATER OUT. Attach the hoses to the water valve. Always use a back-up wrench when tightening the hose to the valve.

5.If the valves are removed to attach the hoses, be sure the O-ring is in the valve before attaching to the union in the cabinet.

NOTE: The valve union is to be hand tight plus an addi- tional 1/4 of a turn; always use back-up wrench on the fit- tings being tightened.

6.Attach flex hoses. Let the universal ends of the hoses hang inside the cabinet. See Table 8 for bend allowances.

NOTE: Be sure the valve handles and P/T ports are in a position that enables them to be opened and closed and used for system readings. Check the swivel ends of the hoses. Gaskets must be in the hose for proper seal.

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