Temperzone OSA 670RKTBQ Reverse Cycle R410A Split System Outdoor Unit

General

The OSA 670RKTBQ outdoor unit is a twin system designed for capacity control (staging) or staggered starting. This unit, when paired with the matching ISD 670KB indoor unit, must be installed in compliance with all national and local safety codes. For installations involving other outdoor/indoor unit combinations, consult temperzone Engineering.

Options

• TZT-100 Room Temperature Controller
• UC6 Service Interface tool

INSTALLATION

Positioning

Fasten the unit securely to a firm, flat horizontal base using the provided mounting rail holes. For roof installations, it is recommended to use a robust structure with anti-vibration mounts or pads. Ensure adequate ventilation in plant room installations. Discharge air must be ducted away from the unit to prevent recirculation, which reduces efficiency. Consult temperzone Support for potential outdoor fan speed adjustments. Never install the unit in a fully enclosed room.

Four drain holes are located in the base of the unit for condensate and/or rainwater drainage.

Dimensions (mm)

Net Weight: 541 kg

Corner Loads (kg): W: 182, X: 88, Y: 88, Z: 183

Minimum Clearances: 2000 mm (Top), 1000 mm (Sides), 500 mm (Front & Rear)

Mounting Centres: 1480 mm (Length), 1231 mm (Width)

Overall Dimensions: 1755 mm (Length), 1470 mm (Width)

Diagram showing unit dimensions and mounting centres.

REFRIGERATION PIPING

General

The OSA 670 is supplied with a refrigerant charge suitable for a 10 m line length. The matched indoor unit comes with a nitrogen holding charge. All OSA 670 units feature brazed pipe connections.

Recommended Pipe Sizes

• Suction pipe (x2): 28 mm OD
• Liquid pipe (x2): 13 mm OD

Line Lengths

The standard unit supports line lengths up to 60 m. For lengths between 60 m and 90 m, refer to the temperzone Split Systems Installation Guide available at www.temperzone.biz/Technical Support. Also, consult the guide for oil charge information. The maximum extended line length is 90 m.

Height Separation Limits

• Outdoor Unit above Indoor Unit: 20 m
• Outdoor Unit below Indoor Unit: 20 m

Vertical Risers

If the outdoor unit is installed above the indoor unit, the suction riser requires trapping at the bottom of the vertical rise and every 8 m thereafter. This ensures proper oil return to the compressor. The trap should be a 'swan neck' curve without changing pipe size.

Piping

1. Use clean, sealed refrigeration-grade piping and accessories specifically designed for R410A.
2. Cut pipes using a pipe cutter only.
3. Employ long radius bends (2x pipe diameter).
4. Insulate the suction (gas) line and seal all insulation joints.
5. A bi-flow type filter dryer can be fitted in the liquid line.
6. Include a process point on the interconnecting pipework.
7. Seal open pipe ends until final connection.
8. Before removing brazed pipe connection seals, reduce the holding charge between connection points and service valves to atmospheric pressure. Warning: Failure to do so may cause injury.

Important: Do not connect System 1 to System 2.

Charging

The unit includes sufficient refrigerant HFC-410A (R410A) for 10 m of pipework. Add 100 g of refrigerant per meter for systems exceeding 10 m. Refer to the wiring diagram specification table for details.

Diagram illustrating pipe length capacity loss on cooling cycle due to pressure drop.

Table showing pipe size, performance loss per additional 10m, and additional pipe length per bend.

ELECTRICAL REQUIREMENTS

All electrical work must be performed by a qualified electrician. The outdoor unit should be wired directly from a distribution board using a circuit breaker or H.R.C. fuse, and a mains isolator preferably located near the unit. Do not use rewirable fuses.

The OSA 670 is equipped with a 24V AC control circuit for thermostats, on/off switches, and/or time clocks. Standard units are compatible with thermostats featuring manual Heat/Cool selection or automatic changeover, provided the thermostat's contact ratings are suitable. Refer to temperzone for recommended thermostats.

A 24-hour power supply to the crankcase heaters is mandatory via the UC6 Controller; otherwise, the warranty will be void.

SYSTEM CHECK TESTS

1. Manually rotate all fan motors to ensure free movement.
2. Verify the tightness of all electrical connections and sign the check label.
3. Turn off the room temperature thermostat and close the mains isolating switch. Allow a four-hour delay for the crankcase heater to remove liquid refrigerant from the compressor oil.
4. Check the supply voltage between each phase and neutral.
5. Confirm the thermostat is correctly wired and set to the desired temperature.
6. Ensure any air filters are correctly installed.
7. Verify that all supply air diffusers are open.

START UP PROCEDURE

Check each system individually before running the complete system. After the four-hour crankcase heater delay, use the supplied Commissioning Sheet to record results. Ideally, use a UC6 Service Interface and associated communication cable (temperzone part no.s 201-000-379 and 201-000-378) to monitor pressures, superheat, set-point, and compressor amps.

1. Select a fan speed (or Auto Fan mode), operating cycle (cool or heat), and room temperature set point appropriate for the season to ensure the compressor starts and runs at high capacity.
2. Turn on the thermostat/external controller. Wait for the compressor to stabilize. Measure and compare the current for each phase feeding the compressor against the values specified on the unit's wiring diagram.
3. Check compressor rotation. Incorrect rotation will prevent pumping and result in minimal current draw. Correct motor rotation by changing the phasing at the main power terminal.
4. Measure the current draw of each fan motor and compare against specified values in the wiring diagram.
5. If a UC6 Service Interface is available, check operating pressures and status via its display screens. If not, fit gauges (designed for R410A) and measure suction and discharge pressures for both refrigeration circuits.
6. Ensure outdoor air fan motors are running smoothly and drawing less than full load amps.
7. Check superheat as per the charging procedure.
8. Verify indoor unit fan belt tension after 20 minutes of operation and adjust if necessary, referring to the Commissioning Sheet.
9. Test the reversing valve operation by running the unit in both heating and cooling modes.
10. Check supply air flow at each outlet.
11. Touch up any damaged outdoor unit paintwork to prevent corrosion.

SETTING SUPPLY AIR FLOW

Consult the ISD/OSA 670 Technical Data pamphlet at www.temperzone.biz for airflow/duct static pressure details. If the indoor air returning to the unit regularly exceeds 50% RH, limit the coil face velocity to 2.5 m/s or less (refer to the Air Handling graph in the Technical Data pamphlet) to prevent water carry-over.

UNIT CONTROLLER (UC6)

The Unit Controller offers system protection features including coil frost protection, de-icing, high head pressure, and low suction pressure cut-outs. It also prevents rapid compressor cycling and refrigerant loss. Various head pressure control methods are employed by temperzone units, managed by the Unit Controller, to optimize performance across a wide operating temperature range.

Refer to the UC6 Controller label on the unit for operation and fault diagnostics. Operating status conditions can be determined using a UC6 Service Interface graphical display.

MAINTENANCE

Weekly For First Four Weeks

1. Check air filters (if fitted) and clean as necessary.
2. Ensure condensate drains are clear.
3. Inspect the compressor compartment for oil stains, which may indicate refrigerant leaks.

Three Monthly (or every 1200 hrs of operation)

• Check and adjust indoor unit fan belt tension if necessary.

Six Monthly

1. Verify the tightness of electrical connections.
2. Check the tightness of fans and motor mountings.
3. Measure suction and discharge operating pressures. Using a UC6 Service Interface avoids refrigerant loss from gauge connection.
4. Replace indoor unit air filters (if fitted).
5. Ensure condensate drains are clear.

Yearly

1. Inspect all refrigerant piping for chafing and vibration.
2. Check air supply at all diffusers.
3. Investigate and correct any excessive noise or vibration.
4. Inspect and repair any insulation or duct damage.
5. Clean lint and dust accumulation from outdoor coil fins. Increase frequency in corrosive environments.
6. Touch up any outdoor unit paintwork damage to prevent corrosion.

IMPORTANT NOTES

The manufacturer reserves the right to change specifications at any time without prior notice. Certified dimensions are available upon request.

This pamphlet is issue no. 6824a, dated 09/18. Q version, OFM height, plant room use.