Long Lineset Instructions

ManualsBrandsBlueridge Manualsair conditioning cooling14.3 SEER 70,000 BTU System Bundle Horizontal Air Conditioner Gas Furnace and Coil

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APPLICATION AND DESIGN GUIDELINES

Refrigerant Piping

DESIGN AND FABRICATION GUIDELINES

Corp. 9351−L9

Revised May 16, 2013

TABLE OF CONTENTS

Introduction 1......................................

Piping Limits 1.....................................

Recommended Components 3.......................

Liquid Line Quick Select 3...........................

Vapor Line Quick Select 6...........................

Long Line Requirements 6..........................

Fundamentals and Theory 7........................

Line Sizing in Detail 9..............................

System Control 21.................................

System Operation 23..............................

Appendix A 24.....................................

Appendix B — XC25 / XP25 Line Set Requirements 33.

Glossary 34.......................................

Introduction

The piping design of any air conditioning system will affect

the performance, reliability, and applied cost of that system.

The design of refrigerant piping systems involves capacity

and efficiency, reliability, oil management, refrigerant

charge, sound level, liquid refrigerant control, modulation

effectiveness and cost. Therefore it is essential that the

installing contractor understand the effect of piping and be

able to make intelligent decisions in order to do the best job

possible on the installation. This material below will clearly

explain the basic effects on system performance of the

piping design.

In most typical installations with lines less than 50 feet, the

line sizes will match up to the connections on the outdoor

unit. However, with installations involving long line sets or

elevation differences between the outdoor unit and the

indoor unit, the piping must be sized carefully. System

performance may be improved even in a typical installation

by optimizing pipe sizes.

IMPORTANT !

The intent of this manual is to represent generally

accepted safe engineering practices. Specifications

and limits outlined in this manual are subject to

change. System design should conform to all codes,

laws and regulations applying at the site at the time

of installation. Additional documents that should be

followed include The Safety Code for Mechanical

Refrigeration and the Code for Refrigeration Piping,

both available from ASHRAE. In addition, the

procedures and limits outlined in this manual do not

supersede local, state or national codes under any

circumstances.

Piping Limits

All expansion valves (TXV) listed in the following tables can

be used in either air conditioner or heat pump systems.

These TXVs incorporate a check valve for heat pump

system applications.

Table 1. Indoor HFC-410A —TXV

Unit Size Catalog Number

2-Ton Y0498

3-Ton Y0499

4-Ton Y0500

5-Ton Y0501

6-Ton Y0502

Table 2. Indoor HCFC-22 —TXV

Unit Size Catalog Number

2-Ton Y0512

3-Ton Y0513

4-Ton Y0514

5-Ton Y0515

6-Ton Y0516

COOLING SYSTEM

HFC-410A

S Total equivalent length = 240 feet (Piping and all

fittings, etc).

NOTE — Length is general guide. Lengths may be more or

less, depending on remaining system design factors.

S Maximum linear (actual) length = 200 feet.

S Maximum linear liquid lift = 60 feet.

NOTE —- Maximum lifts are dependent on total length,

number of elbows, etc that contribute to total pressure drop.

S Maximum length vapor riser = 125 feet.

S Up to 50 linear feet: use rated line sizes listed in unit

specifications or installation instructions.

Summary of content (35 pages)

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Refrigerant Piping DESIGN AND FABRICATION GUIDELINES Corp. 9351−L9 Revised May 16, 2013 APPLICATION AND DESIGN GUIDELINES TABLE OF CONTENTS IMPORTANT ! Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Piping Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Recommended Components . . . . . . . . . . . . . . . . . . . . . . . 3 Liquid Line Quick Select . . . . . . . . . . . . . . . . . . . . . . . . . . .
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S If 51 to 80 linear feet: Crankcase heater required, non-bleed port TXV (see TXV note ) preferred (RFCIV acceptable with maximum vertical of 25 feet). S If 81 - 200 linear feet: Crankcase heater and non-bleed port TXV (see TXV note) required. S Over 200 linear feet: not recommended. TXV NOTE: a) Indoor Factory Installed non-bleed, non-adjustable TXV can be used on the system if it can maintain superheat lower than 25°F at outdoor unit service valve.
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S b) If indoor unit does not have a factory installed TXV, or factory installed TXV needs replacing due to system match, up or the factory TXV is not capable of maintaining low enough superheats, use table 1 for ordering the correct TXV for specific size indoor unit. All of these are indoor non-bleed adjustable thermostat check expansion valves. Superheat adjustment procedures can be found in the TXV kit instructions. S S S If not factory provided, high and low pressure switches are recommended.
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Table 4. Liquid Line Quick Select HCFC-22 UNIT UNIT TONS 012 1 018 1.5 024 2 030 2.5 036 3 042 3.5 048 4 060 5 072 6 090 7.
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Table 5 – HCFC-22 and HFC-410A Vapor Lines UNIT UNIT TONS 012 1 018 1.5 024 2 030 2.5 036 3 042 3.5 048 4 060 5 072 6 090 7.5 120 10 180 (2-COMP) 240 (2-COMP) 15 20 SUCTION / VAPOR LINE SIZE HCFC-22 PRESSURE DROP PSI/100 FEET HFC-410A PRESSURE DROP PSI/100 fEET PREFERRED FOR VERTICAL VAPOR RISES 1/2” 13.0 7.8 X 5/8” 3.1 1.9 5/8” 6.5 3.9 3/4” 2.4 1.4 5/8” 12.0 7.2 3/4” 4.2 2.5 3/4” 6.0 3.6 7/8” 3.1 1.9 3/4” 8.5 5.1 7/8” 4.6 2.8 7/8” 5.9 3.
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Table 7.
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Table 8. Equivalent Length in Feet of Straight Pipe for Valves and Fittings LINE SIZE (OUTSIDE DIAMETER) INCH SOLENOID /GLOBAL GLOBE VALVE ANGLE VALVE 90º LONG* RADIUS ELBOW 45º LONG* RADIUS ELBOW TEE LINE TEE BRANCH 3/8 7 4 0.8 0.3 0.5 1.5 1/2 9 5 0.9 0.4 0.6 2.0 5/8 12 6 1.0 0.5 0.8 2.5 3/4 14 7 1.3 0.6 0.9 3.0 7/8 15 8 1.5 0.7 1.0 3.5 1-1/8 22 12 1.8 0.9 1.5 4.5 1-3/8 28 15 2.4 1.2 1.8 6.0 1-5/8 35 17 2.8 1.4 2.0 7.0 2-1/8 45 22 3.9 1.
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Suction lines and vapor lines must also be carefully sized. Oversized suction lines may result in refrigerant velocities being too low to return oil to the compressor. Undersized suction lines reduce capacity, cause increased refrigerant velocity sound and cause high superheat. Long refrigerant lines have to be carefully planned. Excessive line length can reduce system capacity and lead to reliability problems. The largest penalty for pressure drop is in the suction line.
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Table 10. Refrigerant Charge (Pounds) in 100 feet of Type L Copper Tubing Line Size 3/8” 1/2” 5/8” 5/8” 3/4” 3/4” 7/8” 7/8” 1-1/8” 1-3/8” 1-5/8” 2-1/8 Liquid Liquid Liquid Suction Liquid Suction Liquid Suction Suction Suction Suction Suction HCFC−22 3.8 7.0 11.3 0.3 16.8 0.4 23.4 0.6 1.0 1.6 2.2 3.9 HFC−410A 3.1 5.8 9.2 0.4 13.8 0.6 19.2 0.8 1.3 2.0 2.9 5.0 2.
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Systems with buried refrigerant lines can experience significant or total capacity loss if allowed to transmit heat to the surroundings. In addition, buried lines are susceptible to corrosion which can shorten the life of the system. For this reason, buried lines must rest inside a sealed, watertight, thermally insulated conduit. The lines must not contact the soil for any reason and the conduit must be designed so it cannot collect and retain water.
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HCFC-22 HCFC-22 Figure 4.
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REFRIGERANT HFC-410A LIQUID LINE PRESSURE DROP/VELOCITY At 45_F Evaporating Temperature and 125_F Condensing Temperature 40 30 30 20 15 HFC-410A LIQUID LINE PRESSURE DROP (pounds./100 Feet) 10 9 8 7 6 5 4 3 2 1.5 1.0 .9 .8 .7 .6 .5 .4 .3 .2 30 25 25 20 20 15 15 10 10 9 9 8 8 7 7 6 6 5 5 4 4 3 3 2 2 COOLING CAPACITY (TONS) COOLING CAPACITY (TONS) 12.5 1.5 1.5 1.0 1.0 .9 .9 .8 .8 .7 40 .7 10 9 8 7 6 5 4 3 2 1.5 1.0 .9 .8 .7 .6 .5 .4 .3 .
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HCFC-22 HCFC-22 HCFC-22 Figure 6.
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REFRIGERANT HFC-410A SUCTION LINE PRESSURE DROP/VELOCITY PER 100ft. OF LINE At 45_F Evaporating Temperature and 125_F Condensing Temperature 40 30 20 15 HFC-410A SUCTION LINE PRESSURE DROP (pounds./100 Feet) 10 9 8 7 6 5 4 3 2 1.5 1.0 .9 .8 .7 .6 .5 .3 .2 30 25 25 20 20 15 15 12.5 10 10 9 9 8 8 3000fpm 7 7 6 6 2000fpm 5 5 1500fpm 4 4 1200fpm 3 COOLING CAPACITY (TONS) 12.5 COOLING CAPACITY (TONS) .4 30 3 2 2 600fpm 1.5 1.5 1.0 1.0 .9 .9 .8 .8 .7 .
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EXAMPLE 5 Given: HCFC-22, 10-ton (single stage) condensing unit on ground level with a 10 ton evaporator on the third level above ground and a total of 96 feet (linear) of piping. Unit is charged with 10F subcooling at 125F condensing temperature (280 psi HCFC-22 liquid). See figure 8. 53 FEET 10 TON EVAPORATOR FILTER/DRIER 3 FEET 40 FEET Given: 10−Ton Evaporator 10 TON CONDENSING UNIT Find: Liquid Line Size Solution: Pressure drop cannot exceed 35 psi.
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53 FEET 10 TON EVAPORATOR FILTER/DRIER 3 FEET 10 TON CONDENSING UNIT Because oil separates from the refrigerant in the evaporator, the suction velocity must be adequate to sweep the oil along. Horizontal suction lines require a minimum of 800 fpm velocity for oil entrainment. Suction risers require 1200 fpm minimum and preferably 1500 fpm regardless of the length of the riser. Figure 6 illustrates the relationship between suction line sizing, pressure drop per 100 feet, velocity and cooling tonnage.
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Suction line velocity should not exceed 3000 fpm in order to avoid possible noise complaints. This rule may be slightly exceeded when added velocity is required to entrain oil vertically. 1-1/8 inch outside diameter line with 2.8 psi per 100 feet pressure drop and 1950 fpm velocity is selected. Now calculate pressure drop due to friction loss to determine if this is a good selection. 65 feet of pipe, plus eight elbows (1.8 equivalent feet each, from table 8) = 79.4 feet equivalent length.
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EXAMPLE 3: SUCTION LINE SIZING PROCEDURE Given: 7-1/2 ton condensing unit with evaporator lower than condenser, with 112 feet of piping and four elbows. The piping includes 20 feet of vertical lift and 92 feet of horizontal run. The capacity lost in the total equivalent length of the refrigerant line (using figures 8 and 10) = 1% x (2.4 – 0.5) x 90,000. Btuh lost = 0.01 x (1.9) x 90,000 Btuh lost = 1710 Capacity loss for the line selected is approximately 1.9%.
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Btuh lost = 0.01 x (2.55) x 180,000 How Double Suction Risers Work Btuh lost = 4590 Figure 14 shows a typical double suction riser installation. A trap is installed between the two risers as shown. During partial load operation (figure 15) when gas velocity is not sufficient to return oil through both risers, the trap gradually fills with oil until the second riser is sealed off. When this occurs, the vapor travels up the first riser only.
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From figure 6, select a pipe size for full load capacity. 1-3/8 inch outside diameter. pipe with 3.3 psi drop per 100 feet and 2400 fpm velocity is selected. Now, by using figure 6, find the velocity for the selected pipe size at part load capacity. The part load velocity is approximately 850 fpm. 850 fpm is sufficient to return oil in horizontal runs but not in vertical risers. Slope DOUBLE SUCTION RISER EXAMPLE 40 FT. 10 TON CONDENSING UNIT WITH HOT GAS BYPASS B DOUBLE SUCTION RISER 15 FT.
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The capacity lost in the total equivalent length of the refrigerant line (using figures 6 and 10) = 1% x (3.34 – 0.825) x 120,000. Btuh lost = 0.01 x (2.515) x 120,000 Btuh lost = 3018 Capacity loss for the line selected is approximately 2.5%. Two Stage Applications Many two stage applications will require a reduction in suction riser size to maintain adequate velocity for oil return at low stage. For example, a 5-ton two stage system will normally use a 1-1/8 inch suction line (figure 6).
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HOW TO CHARGE A UNIT USING SUBCOOLING 1. Indoor temperature must be between 70F and 80F. 2. Measure liquid line temperature with temperature sensor. 3. Hook up gauges to liquid and suction lines. 4. Turn on unit (cooling mode if heat pump – high stage if two stage compressor) and operate long enough for pressure to stabilize (at least five minutes). 5. Read condensing temperature from gauge and read liquid line temperature from the thermometer. 6.
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THERMOSTAT Y W G 1 R A/H TRANSFORMER L N TO A/H FAN TO A/H HEAT PUMP DOWN RELAY CONTROL RELAY 2 LOW PRESSURE SWITCH C/U Y1 TO COMPRESSOR CONTACTOR LIQUID LINE SOLENOID VALVE 24 VAC 1 IF NECESSARY REPLACE A/H TRANSFORMER WITH ONE OF ADEQUATE VA CAPACITY. 2 INSTALL LOW PRESSURE CONTROL ON SECTION LINE AT CONDENSING UNIT. TO AVOID OIL MIGRATION INTO THE CONTROL BODY, MOUNT THE LOW PRESSURE CONTROL ABOVE THE HEIGHT OF THE COMPRESSOR. Figure 19.
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OEM low ambient kits are available for all OEM (expansion valve equipped) units. These kits may need to be installed and may need to be supplemented with field installed equipment when applied to systems with long refrigerant lines. Field installed equipment may include any or all of the following: solenoid valve installed in the liquid line at the evaporator, pump-down controls, accumulator, additional crankcase heaters or capacity unloading.
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work, they should be properly isolated. If outside, the isolation material should be properly waterproofed. PIPING INSTALLATION Refrigerant lines must not transmit equipment vibration to any part of the structure. Lines should be supported by isolation hangers. See figure 20. In no case should refrigeration lines be left unsupported and free to touch the structure at any point.
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LINE SET IMPORTANT — Refrigerant lines must not contact structure. INSTALLATION REFRIGERANT LINE SET — INSTALLING VERTICAL RUNS (NEW CONSTRUCTION SHOWN) Line Set Isolation — The following illustrations are examples of proper refrigerant line set isolation: NOTE — Insulate liquid line when it is routed through areas where the surrounding ambient temperature could become higher than the temperature of the liquid line or when pressure drop is equal to or greater than 20 psig.
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Given: Ten ton commercial (single stage) condensing unit on ground with three evaporators above condenser. See figure 22. INSTALL UNIT AWAY FROM WINDOWS Find: Select tube size from figure 8. Solution: Size each segment based on the tons of refrigerant that will flow in the segment. Segment A to B First solve segment A to B (10 tons). Figure 8 indicates that, for a 10-ton system, 5/8 inch outside diameter. Liquid line should be selected (smallest liquid line with acceptable velocity).
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From figure 4, 5/8 inch outside diameter. liquid line with 7 tons capacity has 2.3 psi drop per 100 feet. When we multiply 2.3/100 by 11 equivalent feet, we see that the total friction loss is 0.25 psi. S S S Now, we must add the pressure drop for vertical lift. HCFC-22 pressure drop is 1/2 psi per foot of vertical lift. When multiplied by 10 feet vertical lift we find that pressure drop due to lift = five psi.
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Two feet of pipe, plus one tee (branch side of tee at 3.5 equivalent feet each), plus six ells (1.25 equivalent feet each) = 13 equivalent feet length. From figure 8, ¾ inch outside diameter. suction line with three tons capacity has 8.5 psi drop per 100 feet. When we multiply 8.5/100 by 13 equivalent feet, we see that the total friction loss is 1.11 psi. Segment B to D B to D has a capacity of seven tons. Select from figure 8 a 1-1/8 inch outside diameter. line (smallest line with acceptable velocity).
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THERMOSTATIC EXPANSION VALVE (Air Conditioning System Shown) RFCII REFRIGERANT FLOW CONTROL DEVICE SENSING BULB CAPILLARY TUBE SUCTION LINE LIQUID LINE STRAINER IS PROVIDED TO PROTECT ORIFICE FROM FOREIGN MATTER LIQUID LINE IN VAPOR LINE RFC II METERING DEVICE CUTAWAY EXPANSION VALVE RFC II METERING DEVICE FLARE FITTING FLARE FITTING UP‐FLOW COIL ILLUSTRATED EQUALIZER LINE RFCIV REFRIGERANT FLOW CONTROL DEVICE RFCIII REFRIGERANT FLOW CONTROL DEVICE ORIFICE BODY ORIFICE BODY DISTRIBUTOR DIS
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Putting the Segments Together Next, we must determine if the line sizes we selected will result in satisfactory pressure drop between the condensing unit and each evaporator. To do this we simply add the total pressure drop of each line segment between the condensing unit and each evaporator. Then we convert the pressure drop into a capacity loss for each coil. Remember, there is approximately 1% loss in capacity for each pound of pressure lost to the line.
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Table 14. Operating Temperatures HCFC22 Temperature (°F) Pressure (Psig) °F Psig °F Psig °F Psig °F Psig 40 30 20 10 0 10 12 14 16 18 20 0.6 0.9 10.2 16.6 24.1 32.9 34.9 36.9 39.0 41.1 43.3 22 24 26 28 30 32 34 36 38 40 45 45.5 47.9 50.3 52.7 55.2 57.8 60.5 63.3 66.1 69.0 76.6 50 55 60 65 70 75 80 85 90 95 100 84.7 93.3 102.4 112.2 122.5 133.4 145.0 157.2 170.0 183.6 197.0 105 110 115 120 125 130 135 140 145 150 155 212.9 228.6 245.2 262.5 280.7 299.7 319.6 340.3 362.0 384.6 406.
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Appendix B — XC25 / XP25 Line Set Requirements The XC/XP25 is a variable capacity cooling and heat pump system utilizing variable speed compressor technology. With the variable speed compressor and variable pumping capacity, additional consideration must be given to refrigerant piping sizing and application. The guidelines below are to be used exclusively for the XC/XP25 systems.
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Glossary of Terms accumulator A tank located in the suction line just ahead of the compressor. The purpose of the accumulator is to prevent liquid from entering the compressor. ambient The temperature of the air surrounding an object. For a liquid line passing through an attic, the ambient can approach 180F. OEM cooling and heat pump equipment is designed to provide adequate cooling when the outdoor ambient is 115F. bypass See Hot Gas Bypass. bypass valve A valve used in hot gas bypass systems.
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maximum allowable pressure drop The amount of pressure drop a liquid line can experience before flash gas will begin to form. This number can be calculated if the amount of sub-cooling leaving the condenser is known by subtracting the liquid temperature from the saturated liquid temperature then converting the results into a pressure on the HCFC-22 saturation chart. The difference in pressure between saturated liquid temperature and the liquid temperature is equal to the maximum allowable pressure drop.