Carrier 50VQP084-300 specifications Unit Start-Up Cooling Mode, Unit Start-Up Heating Mode

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Table 15 — 50VQP Unit Operating Limits

AIR LIMITS

COOLING (C)

HEATING (C)

Minimum Ambient Air db

10

10

Rated Ambient Air db

27

20

Maximum Ambient Air db

38

29

Minimum Return Air db/wb

18/15

16

Maximum Return Air db/wb

43/28

29

WATER LIMITS

 

 

Standard Unit

 

 

Minimum Entering Water*

10

16

Maximum Entering Water

49

43

Extended Range Unit†

 

 

Minimum Entering Water*

–1

–6.7

Maximum Entering Water

49

43

LEGEND

 

 

db — Dry Bulb wb — Wet Bulb

*Requires optional insulation package when operating below the dew point.

†With antifreeze, optional extended range insulation and low tem- perature cutout jumper clipped for antifreeze.

If the suction pressure does not drop and the discharge pressure does not rise to normal levels:

1.Turn off power to the unit. Install disconnect tag.

2.Reverse any two of the unit power leads.

3.Reapply power to the unit and verify pressures are correct.

The suction and discharge pressure levels should now move to their normal start-up levels.

When the compressor is rotating in the wrong direction, the unit makes an elevated level of noise and does not provide cooling.

After a few minutes of reverse operation, the scroll com- pressor internal overload protection will open, thus activating the unit lockout. This requires a manual reset. To reset, turn the thermostat on and then off.

NOTE: There is a 5-minute time delay before the compressor will start.

Unit Start-Up Cooling Mode

1.Adjust the unit thermostat to the warmest position. Slowly reduce the thermostat position until the compres- sor activates.

2.Check for cool air delivery at unit grille a few minutes after the unit has begun to operate.

3.Verify that the compressor is on and that the water flow rate is correct by measuring pressure drop through the heat exchanger using P/T plugs. See Table 16. Check the elevation and cleanliness of the condensate lines; any dripping could be a sign of a blocked line. Be sure the condensate trap includes a water seal.

4.Check the temperature of both supply and discharge wa- ter. If temperature is within acceptable range, proceed. If temperature is outside the range, check the cooling refrig- erant pressures.

5.Check air temperature drop across the coil when com- pressor is operating. Air temperature drop should be between 8 and 14 C.

Table 16 — Water Temperature Change

Through Heat Exchanger

 

COOLING

HEATING

WATER FLOW RATE (GPM)

RISE (C)

DROP (C)

 

Min

Max

Min

Max

For Closed Loop: Ground Source or

5.0

6.7

2.2

6.1

Cooling/Boiler Systems at 3.9 L/m per kW

 

 

 

 

For Open Loop: Ground Water Systems at

10.0

12.8

3.9

11.1

2.0 L/m per kW

 

 

 

 

Unit Start-Up Heating Mode

NOTE: Operate the unit in heating cycle after checking the cooling cycle. Allow 5 minutes between tests for the pressure or reversing valve to equalize.

1.Turn thermostat to lowest setting and set thermostat switch to HEAT position.

2.Slowly turn the thermostat to a higher temperature until the compressor activates.

3.Check for warm air delivery at the unit grille within a few minutes after the unit has begun to operate.

4.Check the temperature of both supply and discharge wa- ter. If temperature is within acceptable range, proceed. If temperature is outside the range, check the heating refrig- erant pressures.

5.Once the unit has begun to run, check for warm air deliv- ery at the unit grille.

6.Check air temperature rise across the coil when compres- sor is operating. Air temperature rise should be between 11° C and 17° C after 15 minutes at load.

7.Check for vibration, noise and water leaks.

Flow Regulation — Flow regulation can be accom- plished by two methods. Most water control valves have a flow adjustment built into the valve. By measuring the pressure drop through the unit heat exchanger, the flow rate can be deter- mined using Table 17. Adjust the water control valve until the flow of 0.09 to 0.13 L/s is achieved. Since the pressure con- stantly varies, two pressure gages may be needed in some applications.

An alternative method is to install a flow control device. These devices are typically an orifice of plastic material de- signed to allow a specified flow rate that are mounted on the outlet of the water control valve. Occasionally these valves produce a velocity noise that can be reduced by applying some back pressure. To accomplish this, slightly close the leaving isolation valve of the well water setup.

WARNING

To avoid possible injury or death due to electrical shock, open the power supply disconnect switch and secure it in an open position before flushing system.

Flushing — Once the piping is complete, final purging and loop charging is needed. A flush cart pump of at least 1.5 hp is needed to achieve adequate flow velocity in the loop to purge air and dirt particles from the loop. Flush the loop in both directions with a high volume of water at a high velocity. Follow the steps below to properly flush the loop:

1. Verify power is off.

2. Fill loop with water from hose through flush cart be- fore using flush cart pump to ensure an even fill. Do not allow the water level in the flush cart tank to drop below the pump inlet line to prevent air from filling the line.

3. Maintain a fluid level in the tank above the return tee to avoid air entering back into the fluid.

4. Shutting off the return valve that connects into the flush cart reservoir will allow 345 kPa surges to help purge air pockets. This maintains the pump at 345 kPa.

5. To purge, keep the pump at 345 kPa until maximum pumping pressure is reached.

6. Open the return valve to send a pressure surge through the loop to purge any air pockets in the piping system.

7. A noticeable drop in fluid level will be seen in the flush cart tank. This is the only indication of air in the loop.

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Contents Safety Considerations ContentsGeneral Installation782 50VQP Unit Physical Data406 442A50-8436 50VQP084-150 Unit DimensionsA50-8437 50VQP168-300 Unit DimensionsA50-8468 A50-8466A50-8467 A50-8472 A50-8469A50-8470 A50-8471A50-8479 A50-8476A50-8477 A50-8478A50-8484 A50-8482A50-8485 A50-8483Trap Condensate Drain A50-8486Field Power Supply Wiring Water Quality Guidelines 50VQP084-168 Unit with Complete C Control Typical A50-843850VQP084-168 with Deluxe D Control Typical A50-8439J1 J8 AL1J6J5 50VQP Unit Electrical Data Standard Unit 50VQP Unit Electrical Data Dual Point Power UnitA50-8441 Field Control WiringPRE-START-UP A50- 6268tf.tifPage 50VQP084 Blower Performance Data 50VQP096 Blower Performance Data 456 495 529 561 595 625 656 685 712 741 767 412 455 492 526 563 595 628 658 687 718 745421 459 499 533 569 600 633 663 691 722 749 441 478 513 549 581 614 644 672 703 730 75950VQP120 Blower Performance Data 555 589 618 646 676 702 728 753 779 803 827 850 875 898 511 544 578 608 637 668 695 722 748 776 800 825 849 874 897526 561 592 621 649 679 706 732 758 785 809 833 857 882 544 575 605 633 661 691 717 742 767 794 818 842 867 89050VQP150 Blower Performance Data 618 647 678 708 738 766 793 819 844 867 891 914 937 959 980 581 613 646 678 706 735 763 791 817 842 867 889 912 935 958598 623 656 687 715 744 772 799 825 850 872 896 919 942 963 605 637 666 697 727 755 783 809 835 858 882 905 928 951 97350VQP168 Blower Performance Data 50VQP192 Blower Performance Data BkW 3020.8 Sheave/Mtr 50VQP240 Blower Performance Data 605 633 660 689 714 739 763 790 813 836 858 882 904 50VQP300 Blower Performance Data 581 613 646 678 706 735 763 791 817 842 867 889 538 574 609 640 673 703 733 761 788 812 838 863 888 912553 588 620 653 685 715 744 771 796 822 847 872 896 568 602 633 666 697 726 755 782 806 832 857 881 904Field Selectable Inputs Complete C Control Jumper Settings See FigDeluxe D Control Jumper Settings See Fig Operating Limits DIP Switch Block S2 Accessory 1 Relay OptionsDIP Switch Block S2 Accessory 2 Relay Options START-UP50VQP Unit Operating Limits Unit Start-Up Cooling ModeUnit Start-Up Heating Mode Water Temperature Change Through Heat ExchangerCoaxial Water Pressure Drop Approximate Fluid Volume L Per 30 M of PipeAntifreeze Percentages by Volume OperationComplete C and Deluxe D Board System Test Units with Aquazone Complete C ControlUnits with Aquazone Deluxe D Control Complete C Control LED Code Fault Descriptions Aquazone Deluxe D Control LED Indica ServiceAir Coil Fan Motor Removal TroubleshootingRefrigerant Charging FP1 and FP2 Thermistor Location A50-8163Troubleshooting Unit Does Not Operate Page Page Catalog No Form 50VQP-C1SI 11-10 Copyright 2010 Carrier CorporationForm 62AQ-1SI Pg CL-1 Replaces New Tab 50VQP START-UP ChecklistII. START-UP Book Catalog NoCooling Cycle Analysis Heating Cycle Analysis