Service Record .................................................................................................... 46
General Safety Information
1. Installation and maintenance to be performed only by qualied personnel who are familiar with this type of
equipment.
2. Some units are pressurized with dry air or inert gas.
All units must be evacuated before charging the system with refrigerant.
WARNING: Refrigerant can be harmful if it is inhaled. Refrigerant must be used and recovered responsibly.
Failure to follow this warning may result in personal injury or death.
Inspection
Responsibility should be assigned to a dependable individual at the
job site to receive material. Each shipment should be carefully checked
against the bill of lading. The shipping receipt should not be signed
until all items listed on the bill of lading have been accounted. Check
carefully for concealed damage. Any shortage or damages should be
reported to the delivering carrier. Damaged material becomes the
delivering carrier’s responsibility, and should not be returned to the
manufacturer unless prior approval is given to do so. When uncrating,
care should be taken to prevent damage. Heavy equipment should be
left on its shipping base until it has been moved to the nal location.
Check the serial tag information with invoice. Report any discrepancies
to your Heatcraft Refrigeration Products Sales Representative.
3. Make sure that all eld wiring conforms to the requirements
of the equipment and all applicable national and local codes.
4. Avoid contact with sharp edges and coil surfaces.
They are a potential injury hazard.
5. Make sure all power sources are disconnected before any service work is done on units.
area available through the distributor; the second through fth years,
the purchaser must submit a proof-of-purchase of a compressor and
supply it to Heatcraft Refrigeration Products Warranty Claims for
reimbursement.
Seller makes no express warranties except as noted above. All implied
warranties are limited to the duration of the Express Warranty. Liability
for incidental and consequential damages is excluded.
The forgoing is in lieu of all other warranties, express or implied,
notwithstanding the provisions of the uniform commercial code, the
Magnuson-Moss Warranty - Federal Trade Commission Improvement
Act, or any other statutory or common law, federal or state.
Warranty Statement
Seller warrants to its direct purchasers that products, including Service
Parts, manufactured by SELLER shall be of a merchantable quality, free
of defects in material or workmanship, under normal use and service
for a period of one (1) year from date of original installation, or
eighteen (18) months from date of shipmen
first occurs. Any product covered by this order found to Seller’s
satisfaction to be defective upon examination at Seller’s factory will
at SELLER’s option, be repaired or replaced and returned to Buyer
via lowest common carrier, or SELLER may at its option grant Buyer
a credit for the purchase price of the defective article. Upon return
of a defective product to SELLER’s plant, freight prepaid, by Buyer,
correction of such defect by repair or replacement, and return freight
via lowest common carrier, shall constitute full performance by SELLER
of its obligations hereunder.
SELLER shall have no liability for expenses incurred for repairs made by
Buyer except by prior, written authorization. Every claim on account
of breach of warranty shall be made to SELLER in writing within the
warranty period specied above – otherwise such claim shall be
deemed waived. Seller shall have no warranty obligation whatsoever if
its products have been subjected to alteration, misuse, negligence, free
chemicals in system, corrosive atmosphere, accident, or if operation
is contrary to SELLER’s or manufacturer’s recommendations, or if the
serial number has been altered, defaced, or removed.
MOTOR COMPRESSORS:
Motor compressors furnished by SELLER are subject to the standard
warranty terms set forth above, except that motor compressor
replacements or exchanges shall be made through the nearest
authorized wholesaler of the motor compressor manufacturer (not at
SELLER’s factory) and no freight shall be allowed for transportation of
the motor compressor to and from the wholesaler. The replacement
motor compressor shall be identical to the model of the motor
compressor being replaced. Additional charges which may be incurred
throughout the substitution of other than identical replacements
are not covered by this warranty. An optional, non assignable, four
(4) year extended compressor warranty may be purchased within
the boundaries of the United Sates of America, its territories and
possessions, and Canada. With this extended compressor warranty,
replacements are administered by an authorized compressor
distributor only. Replacements within the rst year of the warranty
2
t by SELLER, whichever
SELLER makes no warranty, express or implied, of fitness for any
particular purpose, or of any nature whatsoever, with respect
to products manufactures or sold by seller hereunder, except as
specically set forth above and on the face hereof. It is expressly
understood and agreed that SELLER shall not be liable to buyer,
or any customer of buyer, for direct or indirect, special, incidental,
consequential or penal damages, or for any expenses incurred by
reason of the use or misuse by buyer or third parties of said products.
To the extent said products may be considered "consumer products,"
As dened in Sec. 101 of the Magnuson-Moss Warranty - Federal Trade
Commission Improvement Act, SELLER makes no warranty of any kind,
express or implied, to "consumers," except as specically set forth above
and on the face hereof.
The following conditions should be adhered to when installing this
unit to maintain the manufacturers warranty:
(a) System piping must be in accordance with good
refrigeration practices.
(b) Inert gas must be charged into the piping during
brazing.
(c) The power supply to the unit must meet the
following conditions:
A. Three phase voltages must be +/ 10% of nameplate ratings. Single
phase must be within +10% or
-5% of nameplate ratings.
B. Phase imbalance cannot exceed 2%.
(d) All control and safety switch circuits must be
properly connected according to the wiring diagram.
(e) The factory installed wiring must not be changed
without written factory approval.
(f) All equipment is installed in accordance with
Heatcraft Refrigeration Products specied minimum
clearances.
Some general rules for evaporator placement which must be
followed are:
1. The air pattern must cover the entire room.
2.
NEVER locate evaporators over doors.
3. Location of aisles, racks, etc. must be known.
4. Location relative to compressors for minimum
pipe runs.
5. Location of condensate drains for minimum run.
The size and shape of the storage will generally determine the
type and number of evaporators to be used and their location. The
following are some typical examples:
Minimum Unit Clearances
Figure 1. Medium Prole and Large Unit Coolers
NOTE:
W = Total width
of evaporator
coil surface.
One evaporator
Figure 2. Low Prole Unit Coolers
NOTE:
H = Total height
evaporator
coil surface.
NOTE: Leave space equal to unit height between bottom of unit and
product. Do not stack product in front of fans.
Two evaporators
One evaporator
Figure 3. Center Mount Unit Coolers
Recommended Maximum - Minimum Dimensions for
E S M T
Max. Min. Max. Min. Max. Min. Max. Min.
25' 2' 20' 3' 40' 3' 40' 6'
Two evaporators
Center Mount Unit Cooler Installations.
3
Unit Cooler Mounting
Most evaporators can be mounted with rod hangers, lag screws, or
bolts. Use 5/16" bolt and washers or rod for up to 250 pounds, 3/8" for
up to 600 pounds and 5/8" for over 600 pounds. Care should be taken
to mount the units level so that condensate drains properly. Note that
some unit cooler designs achieve drain pan slope by using dierent
height mounting brackets. In this situation, the top of the mounting
brackets should be level. Adequate support must be provided to hold
the weight of the unit.
When using rod hangers, allow adequate space between the top of
Figure 4. Large Coolers and Freezers Placement.
the unit and the ceiling for cleaning. To comply with NSF Standard 7,
the area above the unit cooler must be sealed or exposed in such a way
to facilitate hand cleaning without the use of tools. When lagging or
bolting the unit ush to the ceiling, seal the joint between the top and
the ceiling with an NSF listed sealant and ends of open hanger channels
must be sealed to prevent accumulation of foreign matter.
When locating unit coolers in a cooler or freezer, refer to Figures 1
through 4 for guidelines.
NOTE: Always avoid placement of Unit Coolers
directly above doors and door openings.
Baed Unit
Whe re o ne wa ll e vap orato r
mounting is satisfactory.
Cooler or Freezer with Glass
Display Doors
Cooler or Freezers where one wall
will not accommodate all required
evaporators or where air throw
distance must be considered.
Bae
Glass
Display
Door
Allow sucient space between
rear of Unit Cooler and wall to
permit free return of air. Refer to
Figures 1 through 3 for proper
space.
Elevation view of glass display door
cooler or freezer. Be sure air discharge
blows above, not directly at doors.
Provide bae if door extends above
blower level.
Defrost
Many types of control arrangements can be used. In some applications,
it may not be necessary to have scheduled defrost periods. The normal
“o cycle” of the compressor may be adequate to keep the evaporator
coil clear of frost. In other applications, a defrost timer may be necessary
to help assure a clear coil. In a medium temperature environment, “air
defrost” is initiated by the timer, but the evaporator fans continue to
operate to facilitate the melting of frost on the n surface. Other types
of defrost schemes require that the fans on the evaporator shut o
4
during the defrost period.
For most applications, two to four defrost cycles per day should be
adequate. The defrost requirements will vary on each installation so
the defrost settings should be determined by observing the system
operation.
Defrost Thermostat
Adjustable (F25-209 Series)
The defrost duration is determined by the setting of the defrost
termination thermostat. Initially, the thermostat should be set at midrange. This will terminate the defrost at about a 60°F bulb temperature
which will be satisfactory for most applications. A somewhat longer or
shorter defrost can be obtained by adjusting the control clockwise for a
shorter defrost and counterclockwise for a longer defrost. The fan delay
temperature setting of the thermostat is factory set at 25°F. It can be
adjusted upward by turning the adjusting screw next to the duration
adjustment with a small screwdriver. Each complete clockwise rotation
of this screw raises the setting approximately 3°F. This screw should not
be adjusted more than four turns. Making this adjustment also raises
the defrost termination temperature setting of the thermostat by a
similar amount. For example, with the duration setting at mid-range,
the termination temperature would be approximately 60°F. Turning
the adjusting screw one turn would raise the fan delay temperature to
about 28°F as well as changing the termination temperature from 60°F to
63°F. On medium temperature applications it may be necessary to raise
the setting to assure that the thermostat will reset after a defrost.
Adjustable (060-100-00 Series)
This control has an adjustable defrost termination setpoint and an
adjustable dierential for controlling the fan delay. A typical termination
setting is 60°F with a 25°F dierential. Termination setting may be
adjusted to increase/decrease the length of defrost. The dierential
should be adjusted to turn on the fans at 30 to 35°F (Fan Temperature
= Termination Temperature – Dierential). Actual coil temperature will
be 5 to 10°F below this value. Some unit coolers are preset and labeled
at the factory with special settings.
Note: Defrost controls are positioned as determined
by engineering test. Job conditions may require
the sensing device to be relocated for optimal
defrosting.
Bimetal Disc
A bimetal disc type thermostat is wired to the control circuit to terminate
the defrost cycle when the coil temperature reaches approximately 55°F.
The bimetal disc thermostat provides a fan delay to allow moisture on
the coil to freeze after defrost termination.
Note: On systems where the suction temperature is
above approximately 25°F, the fans may not
start for an extended period of time.
On freezer applications, it may be necessary to apply a jumper to the
fan delay on a warm box. This can be corrected by jumping the fan
switch contacts. This will allow the fans to start immediately after
defrost termination. This will disable the fan delay.
If moisture blow-o is encountered without the fan delay, a higher
temperature defrost thermostat can be ordered. This thermostat
terminates defrost at 60°F and prevents the fans from running when
the coil temperature is above 40°F. Refer to the replacement parts list
for the correct number to order.
Table 1. Expansion Valve Selection For 100# Head Pressure Valve
BTUH R-507/R404A R-507/R404A R-22 R-22
at about -20
10° T.D. Sporlan ALCO Sporlan ALCO Sporlan ALCO Sporlan ALCO
3,000-5,000 EGSE 1/2 ZP HFESC-1/2-RZ EGSE 1/2 C HFESC-1/2-RC EGVE 1/2 Z HFESC-1-HZ EGVE 1/2 C HFESC-1/2-HC
5,500-7000 EGSE 1/2 ZP HFESC-1/2-RZ EGSE 1 C HFESC-1/2-RC EGVE 1 ZP HFESC-1-HZ EGVE 1 C HFESC-1-HC
7500-8000 EGSE 1 ZP HFESC-1/2-RZ EGSE 1 C HFESC-1-RC EGVE 1 ZP HFESC-1 1/2-HZ EGVE 1 C HFESC-1-HC
8500-10,000 EGSE 1 ZP HFESC-1-RZ EGSE 11/2 C HFESC-1 1/4-RC EGVE 11/2 ZP HFESC-1 1/2-HZ EGVE 1 C HFESC-1-HC
10,500-11,000 EGSE 1 ZP HFESC-1 1/4-RZ EGSE 11/2 C HFESC-1 1/4-RC EGVE 11/2 ZP HFESC-2-HZ EGVE 11/2 C HFESC-1-HC
11,500-13,000 EGSE 11/2 ZP HFESC-1 1/2-RZ EGSE 11/2 C HFESC-1 1/4-RC EGVE 11/2 ZP HFESC-2-HZ EGVE 11/2 C HFESC-1-HC
13,500-15,000 EGSE 11/2 ZP HFESC-2-RZ EGSE 2 C HFESC-1 1/2-RC EGVE 2 ZP HFESC-2 1/2-HZ EGVE 11/2 C HFESC-2-HC
15,500-17,000 EGSE 2 ZP HFESC-2-RZ EGSE 2 C HFESC-2-RC EGVE 2 ZP HFESC-2 1/2-HZ EGVE 2 C HFESC-2-HC
17,500-20,000 EGSE 2 ZP HFESC-3 1/2-RZ SSE 3 C HFESC-2-RC EGVE 3 ZP HFESC-3-HZ EGVE 2 C HFESC-2 1/2-HC
20,500-24,000 SSE 3 ZP HFESC-3 1/2-RZ SSE 3 C HFESC-3-RC SVE 3 ZP HFESC-3-HZ SVE 3 C HFESC-3-HC
24,500-28,000 SSE 3 ZP HFESC-3 1/2-RZ SSE 4 C HFESC-3-RC SVE 4 ZP HFESC-5 1/2-HZ SVE 3 C HFESC-3-HC
28,500-34,000 SSE 4 ZP HFESC-5-RZ SSE 4 C HFESC-3-RC SVE 5 ZP HFESC-5 1/2-HZ SVE 4 C HFESC-5 1/2-HC
34,500-40,000 OSE 6 ZP HFESC-5-RZ SSE 6 C HFESC-5-RC SVE 8 ZP HFESC-5 1/2-HZ SVE 4 C HFESC-5 1/2-HC
40,500-50,000 OSE 8 ZP HFESC-7-RZ OSE 8 C HFESC-5-RC SVE 10 ZP HFESC-8-HZ SVE 5 C HFESC-5 1/2-HC
50,500-60,000 OSE 9 ZP HFESC-10-RZ OSE 9 C HFESC-7-RC SVE 10 ZP HFESC-8-HZ SVE 8 C HFESC-8-HC
60,500-70,000 OSE 9 ZP HFESC-10-RZ OSE 9 C HFESC-10-RC OVE 15 ZP HFESC-10-HZ SVE 8 C HFESC-8-HC
70,500-80,000 OSE 12 ZP HFESC-10-RZ OSE 12 C HFESC-10-RC OVE 15 ZP HFESC-15-HZ SVE 10 C HFESC-10-HC
80,500-90,000 OSE 12 ZP HFESC-13-RZ OSE 12 C HFESC-10-RC OVE 15 ZP HFESC-15-HZ SVE 10 C HFESC-10-HC
90,500-100,000 OSE 12 ZP HFESC-13-RZ OSE 12 C HFESC-13-RC OVE 15 ZP HFESC-15-HZ OVE 15 C HFESC-15-HC
100,500-110,000 OSE 21 ZP TRAE-20-RZ OSE 21 C HFESC-13-RC OVE 20 ZP HFESC-20-HZ OVE 15 C HFESC-15-HC
110,500-120,000 OSE 21 ZP TRAE-20-RZ OSE 21 C HFESC-13-RC OVE 20 ZP HFESC-20-HZ OVE 15 C HFESC-15-HC
120,500-130,000 OSE 21 ZP TRAE-20-RZ OSE 21 C TRAE-20-RC OVE 20 ZP HFESC-20-HZ OVE 15 C HFESC-15-HC
NOTES:
1. Valve selections assume standard conditions and 100°F vapor-free liquid.
2. Equivalent valve may be used in place of selection.
3. For "Medium Temp R-507," valve designation will use “P” for refrigerant code.
Nozzles supplied with unit coolers are selected for numerous
refrigerants at cataloged operating conditions and 95˚F liquid entering
the expansion valve. If mechanical or another method of subcooling
is used, the nozzle and expansion valve selection should be checked.
For conditions outside those cataloged, use the charts to select a
proper nozzle. Nozzle capacity should be within 135% to 180% of
unit operating condition for optimum coil performance. Nozzles are
available from Sporlan Wholesalers or from Heatcraft Refrigeration
Products. A small nozzle can be drilled larger using the I.D. column in
table 3, page 8. The hole must be accurately centered in the nozzle. A
lathe is preferred for accurate drilling.
may occur and poor evaporator operation may be experienced.
For peak performance, it is important to select an expansion valve with
the correct capacity and selective charge. Thermostatic expansion
valves may be mounted in any position, but they should be installed
as close to the evaporator as possible. For best performance, the outlet
of the expansion valve should be installed directly to the distributor
body. If this is not possible, the distance between the valve outlet and
distributor should not exceed 24 inches. Elbows located between the
expansion valve and distributor will hinder proper distribution and
therefore, are not recommended. Some accessories may, however,
necessitate the use of elbows.
Expansion Valves and Distributor Nozzles
Before installing the expansion valve on the distributor of the
evaporator, the proper distributor nozzle must be installed. Two
nozzles are normally shipped with each evaporator for dierent
refrigerants. Select the nozzle for the refrigerant that will be used.
The size of the nozzles shipped with each evaporator is based on
ordinary conditions, usually 95˚F liquid temperature and a maximum
of 15˚F evaporator TD*. If a mechanical subcooler is to be used in
your system, consult the factory or a representative for distributor
nozzle sizing. This is very important as the nominal capacity of the
nozzle increases as the liquid refrigerant temperature is lowered.
If the correct size nozzle is not installed, poor refrigerant distribution
*Temperature Dierence
(design room temperature minus saturated suction temperature)
Selecting Distributor Nozzle at the Job Site
You must know 4 things:
1. Refrigerant
2. Evaporating Temperature
3. Tons or BTUH
4. Highest Liquid Temperature
Locate the expansion valve bulb on a horizontal length of suction
line as close to the suction header as possible. The bulb should be
clamped tightly on the suction line and insulated with a waterproof
type of insulation. The bulb should never be placed on a coupling or
other obstruction so as to not make 100 % contact with the suction line.
The bulb should never be placed in a trap or downstream of a trap in
a suction line. Locating the bulb on the bottom of a suction line is not
recommended. The bulb should be installed at the 3, 4 or 8, 9 o’clock
position on the suction line. See Figure 5 on page 6.
EXAMPLE: Select a nozzle for R404A, -20˚F suction; 9,400 BTUH, 60˚F liquid entering TXV.
9,400
12,000
= .78 Tons
[1.83 Factor
for 60˚F Liquid]
EXAMPLE: Select a nozzle for R22, 20˚F suction; 67,000
BTUH, 100˚F liquid entering TXV.
67,000
12,000
From Table 3 on page 8 select Size 4 rated at 3.84 tons. We prefer
selecting at 135% - 180% of nominal rating. This is typically two sizes
smaller than the closest tonnage in Table 3.
5.58
3.84
= 5.58 Tons
= 145% of Nominal Rating - okay.
0.78
1.83
From Table 3 on page 8 select Size 3/4 rated at 0.29 tons.
0.42
0.29
Typical selections would be between 135% and 180%.
= .42 Corrected Tons
= 145% of Nominal Rating - okay.
7
Worksheet:
Given Values
Refrigerant ____________________________
Suction Temperature ___________________˚F
BTUH _______________________________
Liquid Temperature _____________________˚F
Calculations: _____ BTUH ÷ 12,000 = _____ Tons
Liquid Correction Factor:
_____________˚F liquid = _____________ Factor
_____ Tons ÷ _____ Factor = ____Corrected Tons
Nozzle Selections (Table 3)
______ Tons ÷ _______ Nozzle Capacity = ______%
(if within 135% to 180%, it is acceptable)
Table 3. Distributor Nozzle Capacities in Tons of Refrigeration
Nozzle Evaporator (Saturated Suction) Temperature °F
Orice R22
Either copper or steel drain lines should be used and properly protected
from freezing. In running drain lines, provide a minimum 1/4 inch per
foot pitch for proper drainage. Drain lines should be at least as large as
the evaporator drain connection. All plumbing connections should be
made in accordance with local plumbing codes. All condensate drain
lines must be trapped, and run to an open drain. They must never be
connected directly to the sewer system. Traps in the drain line must be
located in a warm ambient. We recommend a trap on each evaporator
drain line prior to any tee connections. Traps located outside, or extensive
outside runs of drain line must be wrapped with a drain line heater.
The heater should be connected so that it operates continuously. It
is recommended that the drain line be insulated to prevent heat loss.
A heat input of 20 watts per linear foot of drain line for 0˚F (-18˚C)
room applications and 30 watts per linear foot for -20˚F (-29˚C) rooms
is satisfactory. In freezers, the evaporator drain pan tting should be
included when heating and insulating the drain line.
Inspect drain pan periodically to insure free drainage of condensate.
If drain pan contains standing water, check for proper installation. The
drain pan should be cleaned regularly with warm soapy water.
Figure 7. Condensate Drain Lines
WARNING: All power must be disconnected before clean-
Traps on low temperature units must be outside of refrigerated
enclosures. Traps subject to freezing temperatures must be wrapped
with heat tape and insulated.
NOTE: Always trap single evaporator system drain
lines individually to prevent humidity migration.
ing. Drain pan also serves as cover of hazardous
moving parts. Operation of unit without drain
pan constitutes a hazard.
9
Space and Location Requirements for
Air Cooled Condensing Units and Remote Condensers
The most important consideration which must be taken into account
when deciding upon the location of air-cooled equipment is the
provision for a supply of ambient air to the condenser, and removal of
heated air from the condensing unit or remote condenser area. Where
this essential requirement is not adhered to, it will result in higher
head pressures, which cause poor operation and potential failure of
equipment. Units must not be located in the vicinity of steam, hot air
or fume exhausts. Corrosive atmospheres require custom designed
condensers.
Figure 8. Space and Location Requirements for Condensing Units and Remote Condensers
Another consideration which must be taken is that the unit should be
mounted away from noise sensitive spaces and must have adequate
support to avoid vibration and noise transmission into the building.
Units should be mounted over corridors, utility areas, rest rooms and
other auxiliary areas where high levels of sound are not an important
factor. Sound and structural consultants should be retained for
recommendations.
Walls or Obstructions
The unit should be located so that air may circulate freely and not
be recirculated. For proper air ow and access all sides of the unit
should be a minimum of “W” away from any wall or obstruction. It
is preferred that this distance be increased whenever possible. Care
should be taken to see that ample room is left for maintenance work
through access doors and panels. Overhead obstructions are not
permitted. When the unit is in an area where it is enclosed by three
walls the unit must be installed as indicated for units in a pit.
Units in Pits
The top of the unit should be level with the top of the pit, and
side distance increased to “2W”.
If the top of the unit is not level with the top of pit, discharge
cones or stacks must be used to raise discharge air to the top of
the pit. This is a minimum requirement.
Multiple Units
For units placed side by side, the minimum distance between
units is the width of the largest unit. If units are placed end
to end, the minimum distance between units is 4 feet.
Decorative Fences
Fences must have 50% free area, with 1 foot undercut, a “W”
minimum clearance, and must not exceed the top of unit.
If these requirements are not met, unit must be installed as
indicated for “Units in pits”.
10
Walls or Obstructions for Horizontal Air Flow
* “W” = Total width of the condensing unit or condenser.
Multiple Units with Horizontal Air Flow
Requirements for Remote and Water Cooled
Condensing Units
General Installation
The indoor compressor units are designed to be used with a remote
condenser. The water cooled units are similar, except that they have
an integral water cooled condenser. Inlet and outlet water connections
are to be made in the eld. On units having a compressor water jacket,
incoming water shall be routed through the jacket prior to entering
the condenser. For cleaning purposes, condenser end plates can be
removed to give access to the water tubes. Cleaning is accomplished
by a simple spiral tool powered by an ordinary electric drill. During
installation, allow space for cleaning the condenser. Commercial
equipment of this type is intended for installation by qualified
refrigeration mechanics.
Typical Arrangements
Diagram 1 illustrates a typical piping arrangement involving a remote
condenser located at a higher elevation, as commonly encountered
when the condenser is on a roof and the compressor and receiver are
on grade level or in a basement equipment room.
In this case, the design of the discharge line is very critical. If properly
sized for full load condition, the gas velocity might be too low at
reduced loads to carry oil up through the discharge line and condenser
coil. Reducing the discharge line size would increase the gas velocity
suciently at reduced load conditions; however, when operating at
full load, the line would be greatly undersized, and thereby creating an
excessive refrigerant pressure drop. This condition can be overcome
in one of two of the following ways:
1. The discharge line may be properly sized for the desired pressure
drop at full load conditions and an oil separator installed at the bottom
of the trap in the discharge line from the compressor.
2. A double riser discharge line may be used as shown in Diagram 2.
Line “A” should be sized to carry the oil at minimum load conditions and
the line “B” should be sized so that at the full load conditions both lines
would have sucient ow velocity to carry the oil to the condenser.
Water Regulating Valve
Using this control on the water cooled condensing units, the head
pressure can be maintained by adjusting the ow of water through
the condenser section. This type control is most often located on the
water entering side of the condenser and is regulated by the refrigerant
condensing pressure.
Subcooler
Diagrams 1 and 2 below show typical subcooler piping. Diagram 1
is the preferred connection with receiver as it provides maximum
subcooling. Diagram 2 may be used if the receiver is located far from
the condenser.
Notes:
1. All oil traps are to be as short in radius as possible.
Common practice is to fabricate the trap using three
90 degree ells.
2. Pressure relief valves are recommended at the condenser for protection of the coil.
3. A pressure valve at the high point in the discharge line is recommended to aid in removing non-condensables.
4. The placement of a subcooler should be that it does not interfere with normal airow of the condenser. Increased static of the unit could cause a decrease in system capacity
and fan motor damage.
GPM Requirements
The GPM Requirements table below can be used as a guide for
determining water ow requirements of the condenser. Operation
below the minimum ow rates may result in excessive fouling and
poor heat transfer. Operation above the maximum ow rates risk
premature impingement corrosion and tube failure.
Rigging holes are provided on all units. Caution should be exercised
when moving these units. To prevent damage to the unit housing
during rigging, cables or chains used must be held apart by spacer
bars. The mounting platform or base should be level and located so
as to permit free access of supply air.
Ground Mounting
Concrete slab raised six inches above ground level provides a suitable
base. Raising the base above ground level provides some protection
from ground water and wind blown matter. Before tightening mounting
bolts, recheck level of unit. The unit should in all cases be located with
a clear space in all directions that is at a minimum, equal to the height
of the unit above the mounting surface. A condensing unit mounted in
a corner formed by two walls, may result in discharge air recirculation
with resulting loss of capacity.
Roof Mounting
Due to the weight of the units, a structural analysis by a qualied
engineer may be required before mounting. Roof mounted units should
be installed level on steel channels or an I-beam frame capable of
supporting the weight of the unit. Vibration absorbing pads or springs
should be installed between the condensing unit legs or frame and
the roof mounting assembly.
Access
Provide adequate space at the compressor end of the unit for servicing.
Provide adequate space on the connection side to permit service of
components.
Spring Mounted Compressor
Compressors are secured rigidly to make sure there is no transit damage.
Before operating the unit, it is necessary to follow these steps:
a. Remove the upper nuts and washers.
b. Discard the shipping spacers.
c. Install the neoprene spacers. (Spacers located
in the electrical panel or tied to compressor.)
d. Replace the upper mounting nuts and washers.
e. Allow 1/16 inch space between the mounting nut/
washer and the neoprene spacer. See Figures 9
and 11 below.
Rigid Mounted Compressor
Some products use rigid mounted compressors. Check the compressor
mounting bolts to insure they have not vibrated loose during shipment.
See Figure 10 below.
Figure 9. Spring Mount
Figure 10. Solid Mount for Mobile or Deep
Sump Application.
Figure 11. Spring Mount
12
Condensing Unit Accessories
Suction Filters, Driers, Sight Glasses
There are two types of suction and liquid lter/driers used on
Heatcraft Refrigeration Products units. Replaceable core and/or
sealed units are used, dependent upon the option package ordered.
Suction lters, regardless of type, are always installed upstream of
the compressor suction service valve, and any accumulators or other
options that may be installed. Suction lters are equipped with
“Schrader” type access valves to allow eld measurement of pressure
drop across the device. This allows plugged lters and elements to
be identied very quickly and easily so they can be replaced when
the pressure drop is excessive. Refer to the specic manufacturers’
recommendation on servicing these units by make and model.
Liquid lter/driers, regardless of type, are always installed downstream
of the receiver outlet service valve, and upstream of the liquid line
solenoid valve (if supplied). Liquid line driers may or may not have an
access valve, dependent on the size and application.
The basic servicing of these units is similar to suction lters. Liquid
line driers should be replaced whenever there is evidence of excessive
pressure drop across the lter, or the system becomes contaminated
due to system leaks, compressor burnouts, acid formation, or
moisture accumulation as indicated by the liquid line sight glass.
The sight glass is installed in the main liquid line assembly, downstream
from the receiver outlet service valve, and immediately after the liquid
line drier. The sight glass is designed to give a visual indication of
system moisture content with refrigerant owing. Slight color indication
on a new system is common and will be eliminated during system
evacuation. Generally, it requires no eld service. However, in cases of
extreme acid formation in a system after a compressor burnout, the
acid may damage the sensing element or etch the glass. This would
require that the sight glass be replaced, along with the liquid line drier
after any compressor motor burnout.
Table 6. Recommended Low Pressure Control Settings for Outdoor Air Cooled Condensing Units
* Minimum ambient or box temperature anticipated, high pressure control setting: R-22, 360 PSI; R-404A, R-507, 400 PSI; R-134a, 225 PSI
* The standard preset low pressure switch used for pumpdown is set for 15 PSI cut in / 4 PSI cut out and is a good setting for most pumpdown systems
* ZB Scroll compressors should be set for 25 PSI cut in / 17 PSI cut out (R-404A / R-507)
CAUTION: Fans closest to the headers should not be
cycled on standard temperature or pressure
controls. Dramatic temperature and pressure
changes at the headers as a result of fan
action can result in possible tube failure.
Fan motors are designed for continuous
duty operation.
Fan cycling controls should be adjusted to maintain a mini
mum of (5) minutes on and (5) minutes o. Short cycling of
fans may result in a premature failure of
motor and/or fan blade.
Compressors operating below +10°F SST must have air
owing over the compressor at all times when the compres
sor is running.
-
-
13
Evaporating Temperature (ºF)
Condensin
g
T
emper
atu
r
e (ºF)
Copeland Demand Cooling for Discus L2 Models
R-22, when used in a properly designed and controlled refrigeration
system, is a realistic low temperature refrigerant alternative to R-502,
which was phased out due to its high ozone depletion potential.
However, experience has shown R-22 can present problems as a low
temperature refrigerant because under some conditions the internal
compressor discharge temperature exceeds the safe temperature limit
for long term stability of refrigeration oil. For this reason suction to liquid
heat exchangers are not recommended unless they are necessary to
prevent another potential problem.
The Copeland Demand Cooling System
Copeland's demand cooling system uses modern electronics to provide a
reliable, cost-eective solution to this problem. It is required for all single
stage R-22 applications with saturated suction temperatures below -10˚F.
The Demand Cooling module uses the signal of a discharge head
temperature sensor to monitor discharge gas temperature. If a critical
temperature is reached, the module energizes a long life injection valve
which meters a controlled amount of saturated refrigerant into the
compressor suction cavity to cool the suction gas. Refer to Figure 13.
This process controls the discharge temperature to a safe level. If, for
some reason, the discharge temperature rises above a preset maximum
level, the Demand Cooling module will turn the compressor o (requiring
a manual reset) and actuate its alarm contact. To minimize the amount
of refrigerant which must be injected, the suction gas cooling process
is performed after the gas has passed around and through the motor.
Operating Range
Demand Cooling is designed to protect the compressor from high
discharge temperatures over the evaporating and condensing
temperature ranges shown in Figure 12 at a maximum return gas
temperature of 65˚F.
When Demand Cooling operates, it “diverts” refrigeration capacity
in the form of injected saturated refrigerant from the evaporator to
the compressor. The eect of this diversion on evaporator capacity is
minimal because the diverted capacity is used to cool the gas entering
the compressor. As the gas is cooled, it naturally becomes more
dense, increasing the mass ow through the compressor, which partly
compensates for the capacity diverted from the evaporator.
1. Compressor Return Gas Temperature: Suction lines
should be well insulated to reduce suction line heat gain.
Return gas superheat should be as low as possible
consistent with safe compressor operation. Minimum 20˚F
superheat at the compressor is required.
2. Condensing Temperatures: It is important when using
R-22 as a low temperature refrigerant that condensing
temperatures be minimized to reduce compression ratios
and compressor discharge temperature.
3. Suction Pressure: Evaporator design and system control
settings should provide the maximum suction pressure
consistent with the application in order to have as low a
compression ratio as possible.
In most cases, with floating head systems where condensing
temperatures are low during most of the year, Demand Cooling will
operate primarily as a compressor protection control much as the
oil failure control protects the compressor during periods of low oil
pressure. Demand Cooling will be allowed to operate only during those
periods when condensing temperatures and return gas temperatures
are high or in periods where a system failure (such as an iced evaporator,
an expansion valve which does not control superheat, blocked
condenser, or a failed condenser fan) raises condensing temperatures
or return gas temperatures to abnormally high levels or lowers suction
pressure to abnormally low levels.
Demand Cooling System Design
Figure 12. Demand Cooling Injection
Figure 13. Single Stage Internal Refrigerant Injection
14
Head Pressure Control
Several types of head pressure control systems are available on
condensing units:
A. Dual Valve System. (See section on operation
and adjustment.)
B. Single Valve system. No adjustments are necessary.
(See section on operation.)
C. Ambient Fan Cycle Control. (See section on operation
and adjustment.)
D. No Control.
A. Dual Valve System
Operation and Adjustment
Condensing units with dual valves require sucient charge to partially
ood the condenser during low ambient conditions.
Valve adjustment should be made with gauges connected to the
discharge port of the compressor. Adjustments should be made during
mild or low ambient conditions. Turning the valve stem “clockwise” on
the ORI valve will increase the discharge pressure, while turning the
valve stem “counterclockwise” will decrease the discharge pressure.
If adjustments are made during warm ambient conditions, it may not be
possible to adjust the regulator valve as low as desired. Readjustment
may be necessary once cooler conditions prevail.
The system employs an ORI (open on rise of inlet pressure) valve and
an ORD ( open on rise of dierential pressure) valve. The high pressure
discharge gas is introduced above the liquid in the receiver tank. The
receiver discharge is regulated by the ORI valve.
The discharge pressure of the ORI valve must be adjusted to regulate
the unit for proper operating conditions. Adjust the ORI valve shown
on the following diagram to maintain a discharge pressure of 160 to
180 PSIG.
B. Single Valve System
The standard valve used on high pressure refrigerant systems controls
the head pressure at approximately 180 PSIG. There is no adjustment
for this valve. On low pressure refrigerant systems the valve controls
pressure at approximately 100 PSIG. For energy eciency, the 100 PSIG
valve is sometimes used on high pressure refrigerant systems. When this
is done, refer to Table 1 on page 5 for expansion valve selections.
At condensing pressures above the valve setting, ow enters Port C
and leaves Port R. When the condensing pressure falls below the valve
setting, the valve modulates to permit discharge gas to enter Port D.
Metering discharge gas into the refrigerant ow leaving the condenser
produces a higher pressure at the condenser outlet, reduces the ow,
and causes the level of liquid refrigerant to rise in the condenser.
This “ooding” of the condenser with liquid refrigerant reduces the
available condensing surface, holding the condensing pressure at
the valve setting.
Figure 14. Dual Valve Piping Arrangement
Figure 15. Single Valve Flooding Valve Piping
Arrangement
C. Ambient Fan Cycle Control
This is an automatic winter control method which will maintain a
condensing pressure within reasonable limits by cycling fan motors
in response to outside air temperature. The thermostat(s) should be
eld adjusted to shut o the fan when the condensing temperature
is reduced to approximately 90˚F. Table 7 lists approximate settings
for several system T.D.’s. These settings are approximate as they do not
take into account variations in load.
CAUTION: Under no circumstance should all condenser
motors be allowed to cycle o on one control.
At least one motor shall be wired to operate
at all times. Under most circumstances, the
condenser motor nearest the inlet header
should remain on whenever the compressor
is operating.
With the changes that have taken place in our industry due to the CFC
issue, we have reevaluated our lubricants to ensure compatibility with
the new HFC refrigerants and HCFC interim blends oered by several
chemical producers. As a secondary criteria, it is also desirable that any
new lubricant be compatible with the traditional refrigerants such as
HCFC-22 or R502. This “backward compatibility” has been achieved
with the introduction of the Polyol ester lubricants.
Table 8 below summarizes which oils/lubricants are approved for use
in Copeland compressors:
Polyol Ester Lubricants
Hygroscopicity
Ester lubricants (POE) have the characteristic of quickly absorbing
moisture from the ambient surroundings. This is shown graphically in
Figure 16 where it can be seen that such lubricants absorb moisture
faster and in greater quantity than conventional mineral oils. Since
moisture levels greater than 100 ppm will results in system corrosion
and ultimate failure, it is imperative that compressors, components,
containers and the entire system be kept sealed as much as possible.
Lubricants will be packaged in specially designed, sealed containers.
After opening, all the lubricant in a container should be used at once
since it will readily absorb moisture if left exposed to the ambient.
Any unused lubricant should be properly disposed of. Similarly, work
on systems and compressors must be carried out with the open time
as short as possible. Leaving the system or compressor open during
breaks or overnight MUST BE AVOIDED!
Color
As received, the POE lubricant will be clear or straw colored. After use,
it may acquire a darker color. This does not indicate a problem as the
darker color merely reects the activity of the lubricant's protective
additive.
Oil Level
During Copeland's testing of Polyol ester oil, it was found that this
lubricant exhibits a greater tendency to introduce oil into the cylinder
during ooded start conditions. If allowed to continue, this condition
will cause mechanical failure of the compressor.
A crankcase heater is required with condensing units and it must be
turned on several hours before start-up.
Oil level must not exceed 1/4 sight glass.
Figure 16.
Table 8. Refrigeration Oils
Interims HFC's
Traditional Refrigerants R401A, R401B, R402A HFC-134a,
Refrigeration Oils HCFC-22 (MP-39, MP-66, HP-80) R404A, R507
POE's Mobil EAL ARCTIC 22 CC A A P
ICI (Virginia KMP) EMKARATE RL 32CF A A P
Suniso 3GS P PM
MineralTexaco WF32 P PM NOT OilsCalumet RO15 (Witco) P PM ACCEPTABLE
Sontex 200-LT (White Oil) (BR & Scroll Only)
Witco LP-200 P
A/BZerol 200TD AM PM NOTSoltex Type AB-200 PM ACCEPTABLE
P = Preferred Lubricant Choice A = Acceptable Alternative M = Mixture of Mineral Oil and Alkyl Benzene (AB) with minimum 50% AB.
*(Reprinted by permission from Copeland Corporation)
Mineral Oils
The BR and Scroll compressors use Sontex 200, a “white oil”. This oil is
not suitable for low temperature applications nor is it available through
the normal refrigeration wholesalers. For eld “top-o” the use of 3GS
or equivalent, or Zerol 200TD is permissible, as long as at least 50% of
the total oil charge remains Sontex 200.
Suniso 3GS, Texaco WF32 and Calumet R015 (yellow oils) are available
through normal refrigeration wholesalers. These oils are compatible if
mixed and can be used on both high and low temperature systems.
Polyol Ester Lubricants
The Mobil EAL ARCTIC 22 CC is the preferred Polyol ester due to unique
additives included in this lubricant. ICI Emkarate RL 32S is an acceptable
Polyol ester lubricant approved for use when Mobil is not available.
These POE’s must be used if HFC refrigerants are used in the system.
They are also acceptable for use with any of the traditional refrigerants or
interim blends and are compatible with mineral oils. They can therefore
be mixed with mineral oils when used in systems with CFC or HCFC
refrigerants when Copeland compressors are used. These lubricants
are compatible with one another and can be mixed.
Alkyl Benzenes
Zerol 200TD is an alkyl benzene (AB) lubricant. Copeland recommends
this lubricant for use as a mixture with mineral oil (MO) when using the
interim blends such as R-401A, R-401B and R-402A (MP39, MP66 and
HP80). A minimum of 50% AB is required in these mixtures to assure
proper oil return.
Shell MS 2212 is a 70/30 mixture of AB/MO. If this lubricant is used in a
retrot situation virtually all of the existing MO must be drained prior
to relling with the MS 2212 to assure a minimum 50% AB content.
16
Phase Loss Monitor
The combination phase sequence and loss monitor relay protects the
system against phase loss (single phasing), phase reversal (improper
sequence) and low voltage (brownout). When phase sequence is
correct and full line voltage is present on all three phases, the relay is
energized as the normal condition indicator light glows.
Note: If compressor fails to operate and the normal condition indicator
light on the phase monitor does not glow, then the supplied electrical
current is not in phase with the monitor. This problem is easily corrected
by the following steps:
1. Turn power o at disconnect switch.
2. Swap any two of the three power input wires.
3. Turn power on. Indicator light should glow and compressor
should start.
4. Observe motors for correct rotation.
Recommended Refrigerant Piping Practices
The system as supplied by Heatcraft Refrigeration Products, was
thoroughly cleaned and dehydrated at the factory. Foreign matter
may enter the system by way of the evaporator to condensing unit
piping. Therefore, care must be used during installation of the piping
to prevent entrance of foreign matter.
Install all refrigeration system components in accordance with
applicable local and national codes and in conformance with good
practice required for the proper operation of the system.
The refrigerant pipe size should be selected from the tables on pages
23-29. The interconnecting pipe size is not necessarily the same size
as the stub-out on the condensing unit or the evaporator.
The following procedures should be followed:
(a) Do not leave dehydrated compressors or lter-
driers on condensing units open to the atmosphere
any longer than is absolutely necessary.
(b) Use only refrigeration grade copper tubing, properly sealed against contamination.
(c) Suction lines should slope 1/4" per 10 feet towards the compressor.
(d) Suitable P-type oil traps should be located at
the base of each suction riser of four (4) feet or more
to enhance oil return to the compressor.
(e) For desired method of superheat measurement,
a pressure tap should be installed in each evaporator suction line in the proximity of the
expansion valve bulb.
(f) When brazing refrigerant lines, an inert gas
should be passed through the line at low
pressure to prevent scaling and oxidation inside
the tubing. Dry nitrogen is preferred.
(g) Use only a suitable silver solder alloy on suction
and liquid lines.
(h) Limit the soldering paste or ux to the minimum
required to prevent contamination of the solder
joint internally. Flux only the male portion of the
connection, never the female. After brazing, remove excess ux.
(i) See Table 11 on page 23 for discharge and liquid
drain line sizes for remote condenser connections.
(j) If isolation valves are installed at the evaporator,
full port ball valves should be used.
Refrigerant Pipe Support
1. Normally, any straight run of tubing must be supported in at
least two locations near each end of the run. Long
runs require additional supports. The refrigerant lines should
be supported and fastened properly. As a guide, 3/8 to 7/8
should be supported every 5 feet; 1-1/8 and 1-3/8
every 7 feet; and 1-5/8 and 2-1/8 every 9 to 10
feet.
2. When changing directions in a run of tubing, no corner
should be left unsupported. Supports should be placed a
maximum of 2 feet in each direction from the corner.
3. Piping attached to a vibrating object (such as a compressor
or compressor base) must be supported in such a manner
that will not restrict the movement of the vibrating object.
Rigid mounting will fatigue the copper tubing.
4. Do not use short radius ells. Short radius elbows have
points of excessive stress concentration and are subject to
breakage at these points.
5. Thoroughly inspect all piping after the equipment is
in operation and add supports wherever line vibration
is signicantly greater than most of the other piping.
Extra supports are relatively inexpensive as compared to
refrigerant loss.
Figure 17. Example of Pipe Support
Figure 18. Condensing Unit / Compressor to Wall Support.
17
Suction Lines
Horizontal suction lines should slope away from the evaporator toward
the compressor at the rate of 1/4 inch per 10 feet for good oil return.
When multiple evaporators are connected in series using a common
suction line, the branch suction lines must enter the top of the common
suction line.
For dual or multiple evaporator systems, the branch lines to each
evaporator should be sized for the evaporator capacity. The main
common line should be sized for the total system capacity.
Suction lines that are outside of refrigerated space must be insulated.
See the Line Insulation section on page 31 for more information.
Figure 19. Suction P-Traps.
Suction Line Risers
Prefabricated wrought copper traps are available, or a trap can be made
by using two street ells and one regular ell. The suction trap must be
the same size as the suction line. For long vertical risers, additional
traps may be necessary. Generally, one trap is recommended for each
length of pipe (approximately 20 feet) to insure proper oil movement.
See Figure 19 below for methods of constructing proper suction line
P-traps.
NOTE: A suction line trap must be installed at the
point where piping changes the direction of
refrigerant ow from any horizontal run to an
upward vertical run.
Slope 1/4"
per 10 ft.
toward
compressor
Figure 20. Double Suction Riser Construction
Sized for
Minimum Load
Sized for
Full
Load
Liquid Lines
Liquid lines should be sized for a minimum pressure drop to prevent
“ashing”. Flashing in the liquid lines would create additional pressure
drop and poor expansion valve operation. If a system requires long
liquid lines from the receiver to the evaporator or if the liquid has to
rise vertically upward any distance, the losses should be calculated to
determine whether or not a heat exchanger is required. The use of a
suction to liquid heat exchanger may be used to subcool the liquid to
prevent ashing. This method of subcooling will normally provide no
more than 20˚F subcooling on high pressure systems. The amount of
Sized for
Minimum
Load
Sized for
Full
Load
subcooling will depend on the design and size of the heat exchanger
and on the operating suction and discharge pressures. An additional
benet from the use of the suction to liquid type heat exchanger
is that it can help raise the superheat in the suction line to prevent
liquid return to the compressor via the suction line. Generally, heat
exchangers are not recommended on R-22 low temperature systems.
However, they have proved necessary on short, well insulated suction
line runs to provide superheat at the compressor.
18
Hot Gas Defrost Systems
EVAP. COIL
TXV
PAN LOOP
CHECK VALVE
REVERSE CYCLE DEFROST PIPING
CHECK VALVE
CHECK
VALVE
LIQUID
LINE
SUCTION
LINE
HEAT – X
Hot Gas Defrost systems can be described as reverse cycle, reevap., or alternating evaporator. Please see manual H-IM-HGD for
Mohave™ systems.
Refrigerant Piping
Install all refrigerant components in accordance with applicable
local and national codes and in accordance with good practice
for proper system operation. The thermostatic expansion valve
must be the externally equalized type. It can be mounted inside
the unit end compartment. Mount the expansion valve bulb on
a horizontal run of suction line as close as possible to the suction
header. Use the clamps provided with the valve to fasten the bulb
securely so there is a tight line-to-line contact between the bulb
and the suction line. Suction and hot gas connections are made on
the outside of the unit.
Suction lines should be sloped towards the compressor at the rate
of one (1) inch per ten (10) feet for good oil return. Vertical risers
of more than four (4) feet should be trapped at the bottom with
a P-trap. If a P-trap is used, the expansion valve bulb should be
installed between the unit and the trap.
Reverse Cycle System
The hot gas unit coolers can be used in reverse cycle hot gas
defrost systems using multiple evaporators connected to one
condensing unit. Generally, not more than one-third of the
system defrosts at one time. During the reverse cycle defrost, the
reversing valve, located in the compressor discharge line, diverts
hot gas through the suction line to the evaporator.
See the piping view in the Reverse Cycle Defrost Piping diagram.
The suction line check valve directs the hot gas through the drain
pan loop which prevents condensate in the pan from freezing.
The hot gas exits the loop at the pan loop outlet header and
enters the evaporator through the check valve assembly. As the
hot gas defrosts the coil, heat is removed from the hot gas and
eventually it condenses into a liquid and exits the coil at the
distributor side port. The liquid then ows through the check valve
of the thermostatic expansion valve bypass assembly, around the
thermostatic expansion valve, and into the system liquid line. The
liquid refrigerant then feeds other evaporators on the cooling
cycle, evaporates, and returns to the compressor through their
suction lines.
Three Pipe System
The three pipe system (sometimes called re-evap.) uses three
pipes: one for liquid line, one for suction line, and one for hot gas
line. In addition, a re-evaporator accumulator is used at the suction
outlet of the evaporator. The hot gas is taken from the discharge
line between the compressor and the condenser, through a
hot gas solenoid valve, then to the evaporator drain pan circuit,
distributor tee, through the coil. See the Three-Pipe Defrost Piping
Diagram on p. 20 for typical piping at the evaporator coil.
19
Alternating Evaporator System
EVAP. COIL
TXV
PAN LOOP
THREE-PIPE DEFROST PIPING
CHECK
VALVE
HOT GAS LINE
LIQUID LINE
SUCTION LINE
HEAT – X
In the alternating evaporator hot gas defrost system, a third line is
taken o the compressor discharge line as the re-evap system. It
is piped with solenoids at each evaporator, so that hot gas defrost
is accomplished on one or more evaporators while the remaining
IMPORTANT: It is imperative that with the alternating
evaporator hot gas defrost system, no more that 25% of the
operating refrigeration load be in defrost at any time.
evaporators continue to function in a normal manner. The liquid from
defrosting evaporators is reintroduced to the main liquid line and it
is necessary that 75% or greater capacity be retained in the normal
refrigeration cycle to oset the capacity that is being removed by the
units on the hot gas defrost.
Hot gas line sizes for R-22, R404A and R507
System
Capacity
BTU/Hr
4,0001/21/21/21/21/2
5,0001/21/21/21/21/2
6,0001/21/21/25/85/8
7,0001/21/25/85/85/8
8,0001/25/85/85/85/8
9,0001/25/85/85/85/8
10,0001/25/85/85/85/8
12,0005/85/85/87/87/8
14,0005/85/87/87/87/8
16,0005/85/87/87/87/8
18,0005/87/87/87/87/8
20,0005/87/87/87/87/8
25,0007/87/87/87/81 1/8
30,0007/87/87/81 1/81 1/8
35,0007/87/81 1/81 1/81 1/8
40,0007/81 1/81 1/81 1/81 1/8
45,0007/81 1/81 1/81 1/81 1/8
50,0007/81 1/81 1/81 1/81 1/8
60,0001 1/81 1/81 1/81 3/81 3/8
70,0001 1/81 1/81 3/81 3/81 3/8
80,0001 1/81 1/81 3/81 3/81 5/8
90,0001 1/81 3/81 3/81 5/81 5/8
100,0001 1/81 3/81 3/81 5/81 5/8
255075100150
Equivalent Discharge Length (Ft.)
Note: Use next larger hot gas line size for -200F. and lower sucton
temperatures.
20
Unit Cooler Piping
Pipe size example:
Given: -10°F Freezer with one system having (2) evaporators
• One condensing unit rated at 24,000 BTUH’s @ -20°F SST R404A
refrigerant.
• Two evaporators each rated at 12,000 BTUH’s @ 10°F TD.
• 75 feet of actual line run between condensing unit to rst
evaporator and 20 feet of actual line run between the rst
evaporator and the second evaporator (see gure below).
How to gure line sizes:
1. Determine equivalent line run = actual run + valves and tting
allowances.
2. Use Line Sizing Tables on pages 22-29 to size lines.
3. Note any special considerations.
Evap. 2
Evap. 1
Determine line size 1 (main line from
condensing unit):
1. Main line from the condensing unit to be sized for the total
capacity (balance) of the whole system of 24,000 BTUH’s
(Table 14 and 14A).
2. Refer to 24,000 @75 feet at -20°F SST R404A on the chart.
You will nd the suction line to be 1 1/8" and 1/2" liquid line.
3. Refer to Table 10. For every 1 1/8" 90° elbow you must add
3 equivalent feet of pipe and 2 equivalent feet of pipe for each
1 1/8" tee.
Therefore, total equivalent line run =
Actual line run 75 feet
+ (6) 1 1/8" elbows @ 3' 18 feet
+ (1) 1 1/8" tee @ 2'
Total equivalent line run 95 feet
4. Refer to Table 14A. For 95 total equivalent feet, the suction
line size should be 1 3/8" and the liquid line stays at 1/2" line.
Note: The gray shaded areas on Table 14. For 24,000 BTUH’s, the
maximum suction riser is 1 1/8" to insure proper oil return and pressure
drop from the bottom p-trap to the top p-trap.
2 feet
Fittings in this system:
• (6) 90° elbows in main line plus a 90° turn through
a tee.
• (5) addtional 90° elbows to rst evaporator.
• (4) additional 90° elbows to second evaporator.
Determine line size 2 (evaporators):
1. Line sizing to each evaporator is based on 12,000 BTUH’s and
equivalent run from condensing unit. First evaporator has an 80
ft. run and the second evaporator has a 95 ft. run.
2. Table 14 indicates 7/8" suction for the rst evaporator and Table
14A indicates 1 1/8" suction for the second evaporator.
3. Refer to Table 10. Each 7/8" 90° elbow adds 2 equivalent feet of
pipe. Each 1 1/8" 90° elbow adds 3 equivalent feet and a 90° turn
through a 1 1/8" tee adds 6 equivalent feet.
4. Actual line run (evap 1) 80 feet
+ (5) 7/8" elbows @ 2' 10 feet
+ (1) 90° turn through tee @ 6'
Total equivalent line run 96 feet
Actual line run (evap 2) 95 feet
+ (4) 1 1/8" elbows @ 3'
Total equivalent line run 107 feet
5. Table 14A indicates 1 1/8" suction line and 3/8" liquid line from
main line to both evaporators.
6 feet
12 feet
21
Table 9. Pressure Loss of Liquid Refrigerants in Liquid Line Risers (Expressed in Pressure Drop, PSIG,
and Subcooling Loss, ˚F).
R-134a R-22 R507 & R-404A
Liquid Line Liquid Line Liquid Line
Net Total Discharge Cond. to Discharge Cond. to Discharge Cond. to
Evaporator Equiv. Line Receiver Line Receiver Line Receiver
Capacity Length (O.D.) (O.D.) (O.D.) (O.D.) (O.D.) (O.D.)
The following Tables 12 through 14A on pages 22 through 29 indicate
liquid lines and suction lines for all condensing units for R22, R404A,
R134a, and R507.
When determining the refrigerant line length, be sure to add an
allowance for ttings. See Table 10. Total equivalent length of refrigerant
lines is the sum of the actual linear footage and the allowance for
ttings.
1. Sizes that are highlighted indicate maximum suction line sizes that should be used for risers. Riser size should not exceed horizontal size.
Properly placed suction traps must also be used for adequate oil return.
All sizes shown are for O.D. Type L copper tubing.
2. Suction line sizes selected at pressure drop equivalent to 2˚F. Reduce estimate of system capacity accordingly.
3. Recommended liquid line size may increase with reverse cycle hot gas systems.
4. Consult factory for R-134a operation at winter conditions below 0° ambient.
Heated and insulated receiver required below 0° ambient.
If system load drops below 40% of design, consideration to installing double suction risers should be made.
24
Table 12A. Recommended Line Sizes for R-134a (continued) *
1. Sizes that are highlighted indicate maximum suction line sizes that should be used for risers. Riser size should not exceed horizontal size.
Properly placed suction traps must also be used for adequate oil return.
All sizes shown are for O.D. Type L copper tubing.
2. Suction line sizes selected at pressure drop equivalent to 2˚F. Reduce estimate of system capacity accordingly.
3. Recommended liquid line size may increase with reverse cycle hot gas systems.
4. Consult factory for R-134a operation at winter conditions below 0° ambient.
Heated and insulated receiver required below 0° ambient.
If system load drops below 40% of design, consideration to installing double suction risers should be made.
1. Sizes that are highlighted indicate maximum suction line sizes that should be used for risers. Riser size should not exceed horizontal size.
Properly placed suction traps must also be used for adequate oil return.
All sizes shown are for O.D. Type L copper tubing.
2. Suction line sizes selected at pressure drop equivalent to 2˚F. Reduce estimate of system capacity accordingly.
3. Recommended liquid line size may increase with reverse cycle hot gas systems.
4. If system load drops below 40% of design, consideration to installing double suction risers should be made.
1. Sizes that are highlighted indicate maximum suction line sizes that should be used for risers. Riser size should not exceed horizontal size.
Properly placed suction traps must also be used for adequate oil return.
All sizes shown are for O.D. Type L copper tubing.
2. Suction line sizes selected at pressure drop equivalent to 2˚F. Reduce estimate of system capacity accordingly.
3. Recommended liquid line size may increase with reverse cycle hot gas systems.
4. If system load drops below 40% of design, consideration to installing double suction risers should be made.
27
Table 14. Recommended Line Sizes for R-404A and R507 *
1. Sizes that are highlighted indicate maximum suction line sizes that should be used for risers. Riser size should not exceed horizontal size.
Properly placed suction traps must also be used for adequate oil return.
All sizes shown are for O.D. Type L copper tubing.
2. Suction line sizes selected at pressure drop equivalent to 2˚F. Reduce estimate of system capacity accordingly.
3. Recommended liquid line size may increase with reverse cycle hot gas systems.
4. If system load drops below 40% of design, consideration to installing double suction risers should be made.
28
Table 14A. Recommended Line Sizes for R-404A and R507 (continued) *
1. Sizes that are highlighted indicate maximum suction line sizes that should be used for risers. Riser size should not exceed horizontal size.
Properly placed suction traps must also be used for adequate oil return.
All sizes shown are for O.D. Type L copper tubing.
2. Suction line sizes selected at pressure drop equivalent to 2˚F. Reduce estimate of system capacity accordingly.
3. Recommended liquid line size may increase with reverse cycle hot gas systems.
4. If system load drops below 40% of design, consideration to installing double suction risers should be made.
29
Table 15. Weight of Refrigerants in Copper Lines During Operation (Pounds per 100 lineal feet of type "L" tubing).
Line Size Suction Line at Suction Temperature
O.D. Liquid Hot Gas in Inches Refrigerant Line Line -40˚F -20˚F 0˚F +20˚F +40˚F
In the refrigeration industry “City” and “Tower” are designations of
temperature and ow conditions, not applications. The term “City”
refers to operating conditions where incoming water is 75˚F, and
condensing temperature is 105˚F. “Tower” refers to a higher temperature
relationship which is normally 85˚F, incoming water and 105˚F
condensing temperature.
Water circuits in some condenser models provide a center, or Tower,
outlet connection to allow divided inlet water ow. This extra water
port reduces water velocity, water pressure drop, and condenser wear
in applications such as cooling towers where higher inlet temperatures
and water ows occur.
Water Connections for City
For City water (open system)
high pressure applications,
the Tower connections is
plugged.
Water Connections
for Tower
For Tower usage and low
pressure applications, both
normal water connections
will be used as inlets and
the tower connection as
an outlet.
Figure 21. Water Connections
Leak Testing
After all lines are connected, the entire system must be leak tested. The
complete system should be pressurized to not more than 150 psig with
refrigerant and dry nitrogen (or dry CO2). The use of an electronic type
leak detector is highly recommended because of its greater sensitivity to
small leaks. As a further check it is recommended that this pressure be
held for a minimum of 12 hours and then rechecked. For a satisfactory
installation, the system must be leak tight.
Line Insulation
After the nal leak test, refrigerant lines exposed to high ambient
conditions should be insulated to reduce heat pickup and prevent the
formation of ash gas in the liquid lines. Suction lines must always be
insulated with 3/4" wall Armstrong “Armaex” or equal. When required,
Liquid lines should be insulated with 1/2 inch wall insulation or better.
The insulation located in outdoor environments should be protected
from UV exposure to prevent deterioration of insulating value.
Evacuation
CAUTION: Do not use the refrigeration compressor
to evacuate the system. Do not start the
compressor while it is in a vacuum.
Evacuation and Leak Detection
Due to the smaller molecule size of HFC’s, they will tend to leak more
readily than CFC’s. Consequently, it is of the utmost importance
that proper system evacuation and leak detection procedures be
employed.
Copeland recommends a minimum evacuation to 500 microns. In
addition, a vacuum decay test is strongly recommended to assure there
is not a large pressure dierential between the system and vacuum
pump. Good evacuation processes include frequent vacuum pump oil
changes and large diameter, short hose connections to both high and
low sides of the system preferably using bronze braided hose.
Leak detection can be carried out in the conventional manner.
If HCFC or CFC tracer gas is used, care must be taken to completely
remove all traces of the gas prior to introducing HFC’s.
Electronic leak detectors are now available that will sense HFC’s. This
is considered preferable since it removes the possibility of chlorine
remaining in the system after leak testing with HCFC’s and/or CFC’s.
There is a view that even small quantities of chlorine may act as a
catalyst encouraging copper plating and/or corrosion and should
therefore be avoided.
WARNING: HFC-134a has been shown to be
combustible at pressure as low as 5.5 psig
(at 350˚F) when mixed with air at
concentrations more than 60% air
by volume.
At lower temperature, higher pressures are
required to support combustion. Therefore,
air should never be mixed with HFC-134a
for leak detection.
A good, deep vacuum pump should be connected to both the low and
high side evacuation valves with copper tube or high vacuum hoses
(1/4" ID minimum). If the compressor has service valves, they should
remain closed. A deep vacuum gauge capable of registering pressure
in microns should be attached to the system for pressure readings.
A shut o valve between the gauge connection and vacuum pump
should be provided to allow the system pressure to be checked after
evacuation. Do not turn o vacuum pump when connected to an
evacuated system before closing shut o valve.
The vacuum pump should be operated until a pressure of 1,500 microns
absolute pressure is reached — at which time the vacuum should be
broken with the refrigerant to be used in the system through a drier
until the system pressure rises above “0” psig.
NOTE: Refrigerant used during evacuation cannot
be vented. Reclaim all used refrigerant.
EPA regulations are constantly being
updated to ensure your procedure follows
correct regulations.
Repeat this operation a second time.
Open the compressor service valves and evacuate the entire system
to 500 microns absolute pressure. Raise the pressure to 2 psig with
the refrigerant and remove the vacuum pump.
Within the last several years, manufacturers have developed uorescent
dye leak detection systems for use with refrigerants. These dyes mix
with the lubricant and, when exposed to an ultraviolet light “uoresce,”
indicates the location of leaks. Copeland has tested and approved
the Rigid “System Safe” dye and found it to be compatible with the
compressor materials in systems.
31
Refrigerant Charging Instructions
Check Out and Start Up
1. Install a liquid line drier in the refrigerant supply line between
the service gauge and the liquid service port of the receiver. This
extra drier will insure that all refrigerant supplied to the system is
clean and dry.
2. When initially charging a system that is in a vacuum, liquid
refrigerant can be added directly into the receiver tank.
3. Check equipment catalog for refrigerant capacity. System
refrigerant capacity is 90% of receiver capacity. Do not add more
refrigerant than the data tag indicates, unless the line run exceeds
25ft. Then, add additional refrigerant as per the chart on page 30.
Weigh the refrigerant drum before charging so an accurate record
can be kept of the weight of refrigerant put in the system.
4. Start the system and nish charging until the sight glass indicates
a full charge and the proper amount has been weighed in. If the
refrigerant must be added to the system through the suction
side of the compressor, charge in vapor form only. Liquid charging
must be done in the high side only or with liquid metering devices
to protect the compressor.
Low Head Pressure Systems
If you are charging the system by using a clear sight glass as an indication
of proper charge the following must be considered.
Check the condensing temperature. It must be above 105˚F. If not, it will
be necessary to reduce the amount of air going through the condenser
from fans still running. Simply reduce the eective condenser face area
to raise the discharge pressure above the equivalent 105˚F condensing
temperature and then proceed to charge to clear the sightglass. Adjust
evaporator superheat at this time. Return to full condenser face area
and allow the system to balance.
Field Wiring
WARNING: All wiring must be done in accordance with
The eld wiring should enter the areas as provided on the unit. The
wiring diagram for each unit is located on the inside of the electrical
panel door. All eld wiring should be done in a professional manner
and in accordance with all governing codes. Before operating unit,
double check all wiring connections, including the factory terminals.
Factory connections can vibrate loose during shipment.
1. The serial data tag on the unit is marked with the electrical
characteristic for wiring the unit.
2. Consult the wiring diagram in the unit cooler and in the con
densing unit for proper connections.
3. Wire type should be of copper conductor only and of the
proper size to handle the connected load.
4. The unit must be grounded.
5. For multiple evaporator systems, the defrost termination
controls should be wired in series. Follow the wiring diagrams
for multiple evaporator systems carefully. This will assure complete defrost of all evaporators in the system.
6. Multiple evaporator systems should operate o of one thermo
stat.
7. If a remote defrost timer is to be used, the timer should be
located outside the refrigerated space.
8. For air cooled condensers, due to multiple low amp motors, we
recommend using time delay fuse protection instead of circuit
breakers.
applicable codes and local ordinances.
-
After the installation has been completed, the following points should
be covered before the system is placed in operation:
(a) Check all electrical and refrigerant connections.
Be sure they are all tight.
(b) Observe compressor oil level before start-up. The oil level should be at or slightly above the 1/4 level of the sight glass. Refer to Table 8 on page 16 for proper compressor oil.
(c) Remove upper mounting nuts on the compressor feet. Remove the shipping spacers. Install the neoprene washers onto the compressor feet. Replace the upper mounting nuts and washers, allowing 1/16" space between the mounting nut and the neoprene spacer.
(d) Check high and low pressure controls, pressure regulating valves, oil pressure safety controls, and all other safety controls, and adjust if necessary.
(e) Check the room thermostat for normal operation and adjust.
(f ) Wiring diagrams, instruction bulletins, etc. attached to the condensing units should be read and led for future reference.
(g) All fan motors on air cooled condensers, evaporators, etc. should be checked for proper rotation. Fan motor mounts should be carefully checked for tightness and proper alignment.
(h) Electric and hot gas evaporator fan motors should be temporarily wired for continuous operation until the room temperature has stabilized.
(i) Observe system pressures during charging and initial operation. Do not add oil while the system is short of refrigerant unless oil level is dangerously low.
(j) Continue charging until system has sucient refrigerant for proper operation. Do not overcharge. Remember that bubbles in a sight glass may be caused by a restriction as well as a shortage of refrigerant.
(k) Do not leave unit unattended until the system has reached normal operating conditions and the oil charge has been properly adjusted to maintain the oil
level between 1/4 and bottom of the sight glass.
(l) Make sure all Schrader valve caps are in place and tight
CAUTION: Extreme care must be taken in starting
compressors for the rst time after system
charging. At this time, all of the oil and most
of the refrigerant might be in the compressor
creating a condition which could cause
compressor damage due to slugging.
Activating the crankcase heater for 24 hours
prior to start-up is required. If no crankcase
heater is present, then directing a 500 watt
heat lamp or other safe heat source on the
lower shell of the compressor for approximately
thirty minutes will be benecial in eliminating this condition which might never reoccur.
WARNING:
-
dependent. If noisy, change phase of input
wiring.
Scroll compressor is directional
32
Operational Check Out
System Balancing - Compressor Superheat
After the system has been charged and has operated for at least
two hours at normal operating conditions without any indication of
malfunction, it should be allowed to operate overnight on automatic
controls. Then a thorough recheck of the entire system operation
should be made as follows:
(a) Check compressor discharge and suction pressures.
If not within system design limits, determine why
and take corrective action.
(b) Check liquid line sight glass and expansion valve
operation. If there are indications that more refrigerant is required, leak test all connections and
system components and repair any leaks before
adding refrigerant.
(c) Observe oil level in compressor crankcase sight
glass. Add oil as necessary to bring level to bottom
1/4 of the sight glass.
(d) Thermostatic expansion valves must be checked
for proper superheat settings. Feeler bulbs must be
in positive contact with the suction line and should
be insulated. Valves set at high superheat will lower
refrigeration capacity. Low superheat promotes
liquid slugging and compressor bearing washout.
(e) Using suitable instruments, carefully check line
voltage and amperage at the compressor terminals.
Voltage must be within 10% of that indicated on the
condensing unit nameplate. If high or low voltage is
indicated, notify the power company. If amperage
draw is excessive, immediately determine the cause
and take corrective action. On three phase motor
compressors, check to see that a balanced load is
drawn by each phase.
(f) The maximum approved settings for high pressure
controls on our air cooled condensing equipment
is 425 psig. On air cooled systems, check as follows:
Disconnect the fan motors or block the condenser inlet
air. Watch high pressure gauge for cutout point.
Recheck all safety and operating controls for proper
operation and adjust if necessary.
(g) Check defrost controls for initiation and termination
settings, and length of defrost period. Set fail safe at
length of defrost + 25%.
Example: 20 minute defrost + 5 minutes
= 25 minute fail safe
(h) Check drain pan for proper drainage.
(i) Check winter head pressure controls for pressure
setting.
(j) Check crankcase heater operation if used.
(k) Install instruction card and control system diagram for
use of building manager or owner.
IMPORTANT: In order to obtain the maximum capacity from
a system, and to ensure trouble-free operation, it is necessary to balance each and every
system.
This is extremely important with any refrigeration system.
The critical value which must be checked is suction superheat.
Suction superheat should be checked at the compressor as
follows:
1. Measure the suction pressure at the suction service
valve of the compressor and determine the saturation
temperature corresponding to this pressure from a
“Temperature-Pressure” chart.
2. Measure the suction temperature of the suction line
about one foot back from the compressor using an
accurate thermometer.
3. Subtract the saturated temperature from the actual
suction line temperature. The dierence is superheat.
Too low a suction superheat can result in liquid being returned to the
compressor. This will cause dilution of the oil and eventual failure of
the bearings and rings or in the extreme case, valve failure.
Too high a suction superheat will result in excessive discharge
temperatures which cause a break down of the oil and results in piston
ring wear, piston and cylinder wall damage.
It should also be remembered that the system capacity decreases as the
suction superheat increases. For maximum system capacity, suction
superheat should be kept as low as is practical. Copeland mandates a
minimum superheat of 20˚F at the compressor. We recommend that
the superheat at the compressor be between 20˚F and 30˚F.
If adjustments to the suction superheat need to be made,
the expansion valve at the evaporator should be adjusted.
See instructions on page 34.
NOTE: All adjustable controls and valves must be eld
adjusted to meet desired operation. There are no
factory preset controls or valve adjustments.
This includes low pressure, high pressure,
adjustable head pressure systems and expansion
valves.
33
Evaporator Superheat
General Sequence of Operation
Check Your Superheat. After the box temperature has reached or is
close to reaching the desired temperature, the evaporator superheat
should be checked and adjustments made if necessary. Generally,
systems with a design TD of 10˚F should have a superheat value of 6˚
to 10˚F for maximum eciency. For systems operating at higher TD’s,
the superheat can be adjusted to 12˚ to 15˚ ˚F as required.
NOTE: Minimum compressor suction superheat of 20˚F may override these recommendations
on some systems with short line runs.
To properly determine the superheat of the evaporator, the following
procedure is the method Heatcraft recommends:
WARNING: If the condensing unit has no ooded con
denser head pressure control, the condens
-
ing unit must have the discharge pressure
above the equivalent 105˚F condensing
pressure. See refrigerant charging instruc
-
tions on page 32.
1. Measure the temperature of the suction line at the point
the bulb is clamped.
2. Obtain the suction pressure that exists in the suction line
at the bulb location by either of the following methods:
a. A gauge in the external equalized line will indicate the
pressure directly and accurately.
b. A gauge directly in the suction line near the evaporator or directly in the suction header of the
evaporator will yield the same reading as 2a above.
Refrigeration Cycle
1. Power is supplied to the timer at terminals “1” and “N”.
2. The fan delay and the defrost termination thermostat is closed in the
fan delay position and open in the defrost termination position.
The unit cooler fans run continuously.
3. The defrost heaters are o.
4. The room thermostat closes when the temperature rises
above the desired setting.
5. The liquid line solenoid is energized and opens, which allows liquid
refrigerant to ow through the unit cooler.
6. The low pressure control closes when the suction pressure rises
above the cutin setting of the control.
7. On systems with oil pumps, the oil safety control is closed. If the net
oil pressure is less than 9 PSIG for more than 120 seconds, the oil
safety opens, thus breaking the circuit to the compressor contactor
holding coil. The compressor will not operate. This control is reset
manually and must be reset before the compressor can be
restarted.
8. The compressor contactor closes. The compressor and co nde nse r
fan start simultaneously.
9. The room temperature gradually decreases to the desired
temperature.
10. Once the desired temperature is reached, the thermostat opens and
the liquid line solenoid closes, stopping refrigerant ow through the
evaporator.
11. Suction pressure decreases and the compressor contactor opens
when the pressure drops below the cutout setting on the low pressure
control. The compressor and condenser fan stop running.
12. This cycle is repeated as many times as necessary to satisfy the room
thermostat.
13. Frost starts to form on the evaporator coil and continues to form until
the defrost cycle is initiated.
3. Convert the pressure obtained in 2a or 2b above to
saturated evaporator temperature by using a
temperature-pressure chart.
4. Subtract the saturated temperature from the actual
suction line temperature. The dierence is Superheat.
Alternative Superheat Method
The most accurate method of measuring superheat is found by
following the previous procedure, Temperature/Pressure method.
However, that method may not always be practical. An alternative
method which will yield fairly accurate results is the temperature /
temperature method:
1. Measure the temperature of the suction line at the
point the bulb is clamped (outlet).
2. Measure the temperature of one of the distributor
tubes close to the evaporator coil (inlet).
3. Subtract the inlet temperature from the outlet
temperature. The dierence is Superheat.
This method will yield fairly accurate results as long as the pressure
drop through the evaporator coil is low.
Defrost Cycle
1. The defrost cycle starts automatically by the timer at
predetermined times. Typical settings are two to four
defrost cycles per day for freezers. For heavier frost loads
additional settings may be required.
2. Switch “2” to “4” opens in the time clock which breaks the
circuit to the room thermostat, liquid line solenoid, and
evaporator fan motors, allowing the compressor to pump
down and shut o. Simultaneously switch “1” to “3” closes
in the timer allowing current to ow to one side of the
defrost heater contactor. When the compressor shuts o,
an auxiliary contact will send power to the contactor holding
coil; thus, energizing the defrost heaters.
3. The heaters raise the temperature of the coil to 32
causing the frost to melt o the coil.
4. When the coil warms to 45˚F to 55˚F, the defrost
termination thermostat closes, which allows current to the
switching solenoid in the timer allowing the refrigeration
cycle to begin again.
5. The evaporator heaters are o. If the termination
thermostat fails to close, the fail-safe set on the timer will
terminate defrost.
6. The low pressure control closes and the compressor will
start.
7. When the coil temperature reaches 23˚F to 30˚F, the fan
delay closes. This allows the current to ow to the fan
motors. The fan motors start running.
8. The system will now operate in the refrigeration cycle until
another defrost period is initiated by the timer.
˚
F
34
Electric Defrost Troubleshooting
The electric defrost units are relatively simple and trouble-free in operation:
Timer
If the system does not go through its proper sequence , check timer operation through a defrost cycle. Check for loose wires or
terminals. Before replacing timer, check other components.
Operation of Paragon Timer
To set time of day grasp knob which is in the center of the inner (fail-safe) dial and rotate it in a counter-clockwise direction. This
will cause the outer (24 hour) dial to revolve. Line up the correct time of day on the outer dial with the time pointer. Do not try to
set the time control by grasping the other (24 hour) dial. Place pins in the outer dial at the time of day that defrost is required.
Operation of Grasslin Timer
To set the time, turn the minute hand clockwise until the time of day (and AM or PM) on the outer dial is aligned with the triangle
marker on the inner dial. Do not rotate minute hand counter-clockwise. Move the white tab (tripper) on the outer dial outward
at each desired initiation time. Each white tab (tripper) is a 15 minute interval and provides 15 minutes of defrost. For longer
defrost duration, move additional tabs (following in time) from the initiation tab. For example, if a 45 minute defrost is to start
at 7:00 AM, move the tabs outward that lie between 7:00 - 7:15, 7:15 - 7:30 and 7:30 - 7:45 on the AM side of the dial. The defrost
will initiate at 7:00 AM and time terminate at 7:45 AM (if temperature termination does not occur rst). For models with plastic
cover on timer assembly; re-install cover after adjustment.
Fan Motor
If the motor does not operate or it cycles on thermal overload, remove motor leads from terminal block and apply correct voltage
across the leads. If motor still does not operate satisfactorily, it must be replaced. Before starting the unit, rotate fan blades to
make sure they turn freely and have sucient clearance.
Fan Delay & Defrost Termination Control
This control is a single pole double throw switch. The red lead wire is wired to common. The black wire is wired in series with
the fan motors. The brown wire is wired in series with the defrost termination solenoid in the timer. The brown and red contacts
close and the black and red contacts open when the temperature is above 55ºF. The black and red contacts close and the brown
and red contacts open when the temperature is below 35ºF.
On initial “pull down” of a warm box the fan will not start until the coil temperature reaches approximately 35ºF. If the box is still
comparatively warm (60ºF) when the fan starts, then blowing this warm air over the coil may cause it to warm up to 55ºF and thus
stop the fan. Therefore, the fan may recycle on initial “pull down.” This control cannot be adjusted.
If the fan motor fails to start when the control is below 35ºF, disconnect the fan motor leads and check the motor as described
for fan motors. Also check whether current is being supplied at “N” and “4” from the timer. The fan delay control must be below
35ºF when checking for a closed circuit.
Defrost Heater
If unit shows very little or no defrosting and does not heat, disconnect heater and check to nd if it is burned out. To test, apply
correct voltage across heater or use continuity ashlight battery tester.
Drain Pan
If drain pan has an ice build-up, drain line may be frozen. The drain line should be pitched sharply and exit cabinet as quickly
as possible. Sometimes location and ambient at the drain outside of cabinet may cause freeze-up. A drain line heater may be
required to correct the freeze-up. Any traps in the drain line must be located in a warm ambient.
NOTE: After correcting faulty condition it is
essential that the coil and unit be free of
ice before placing unit back on automatic
operation.
35
NOTES:
1. Lockout relays or normally closed switch of auxiliary
contact on the compressor contactor may be wired to
defrost contactor. Its purpose is to prevent energizing
of the defrost heaters until the compressor has pumped
down and stopped, thus keeping power demand to a
minimum.
2. If the control voltage is to remain energized for any
period of time with the compressor disabled, remove the
defrost clock pins to prevent the defrost heaters from
energizing.
3. A Preventative Maintenance schedule should be set up
as soon as possible after start-up to maintain equipment
integrity.
Table 16. Evaporator Troubleshooting Chart
SYMPTOMS POSSIBLE CAUSES POSSIBLE CORRECTIVE STEPS
Fan(s) will not operate. 1. Main switch open. 1. Close switch.
2. Blown fuses. 2. Replace fuses. Check for short
circuits or overload conditions.
3. Defective motor. 3. Replace motor.
4. Defective timer or defrost thermostat. 4. Replace defective component.
5. Unit in defrost cycle. 5. Wait for completion of cycle.
6. Coil does not get cold enough to 6. Adjust fan delay setting of thermostat.
reset thermostat. See Defrost Thermostat Section of
this bulletin.
Room temperature too high. 1. Room thermostat set too high. 1. Adjust thermostat.
2. Superheat too high. 2. Adjust thermal expansion valve.
5. Unit cooler located too close to doors. 5. Relocate unit cooler or add strip curtain
to door opening.
6. Heavy air inltration. 6. Seal unwanted openings in room.
Ice accumulating on ceiling 1. Defrost duration is too long. 1. Adjust defrost termination thermostat.
around evaporator and/or on 2. Fan delay not delaying fans after 2. Defective defrost thermostat or not
fan guards venturi or blades. defrost period. adjusted properly.
3. Defective defrost thermostat or timer. 3. Replace defective component.
4. Too many defrosts. 4. Reduce number of defrosts.
Coil not clearing of frost during 1. Coil temperature not getting above 1. Check heater operation.
defrost cycle. freezing point during defrost. 2. Adjust timer for more defrost cycles.
2. Not enough defrost cycles per day. 3. Adjust defrost thermostat or timer for
3. Defrost cycle too short. longer cycle.
4. Defective timer or defrost thermostat. 4. Replace defective component.
Ice accumulating in drain pan 1. Defective heater. 1. Replace heater.
2. Unit not pitched properly. 2. Check and adjust if necessary.
3. Drain line plugged. 3. Clean drain line.
4. Defective drain line heater. 4. Replace heater.
5. Defective timer or thermostat. 5. Replace defective component.
2. Located too close to door or opening. 2. Relocate evaporator.
3. Defrost termination set too low. 3. Adjust defrost termination setting
higher.
4. Incorrect or missing distributor nozzle. 4. Add or replace nozzle with appropriately
sized orice for conditions.
36
Table 17. System Troubleshooting Chart
PROBLEM POSSIBLE CAUSES POSSIBLE CORRECTIVE STEPS
Compressor will not run 1. Main switch open. 1. Close switch.
2. Fuse blown. 2. Check electrical circuits and motor winding
for shorts or grounds. Investigate for possible overloading. Replace fuse after
fault is corrected.
3. Thermal overloads tripped. 3. Overloads are automatically reset. Check
unit closely when unit comes back on line.
4. Defective contactor or coil. 4. Repair or replace.
5. System shut down by safety devices. 5. Determine type and cause of shutdown and
correct it before resetting safety switch.
6. No cooling required. 6. None. Wait until calls for cooling.
7. Liquid line solenoid will not open. 7. Repair or replace coil.
8. Motor electrical trouble. 8. Check motor for open windings, short circuit
or burn out.
9. Loose wiring. 9. Check all wire junctions. Tighten all
terminal screws.
10. Phase loss monitor inoperative. 10. Refer to page 17.
Compressor noisy or vibrating 1. Flooding of refrigerant into crankcase. 1. Check setting of expansion valves.
2. Improper piping support on suction or 2. Relocate, add or remove hangers.
liquid line.
3. Worn compressor. 3. Replace.
4. Scroll compressor rotation reversed. 4. Rewire for phase change.
High discharge pressure 1. Non-condensables in system. 1. Remove the non-condensables.
2. System overcharges with refrigerant. 2. Remove excess.
3. Discharge shuto valve partially closed. 3. Open valve.
4. Fan not running. 4. Check electrical circuit.
5. Head pressure control setting. 5. Adjust.
6. Dirty condenser coil. 6. Clean.
Low discharge pressure 1. Faulty condenser temperature regulation. 1. Check condenser control operation.
2. Suction shuto valve partially closed. 2. Open valve.
3. Insucient refrigerant in system. 3. Check for leaks. Repair and add charge.
4. Low suction pressure. 4. See corrective steps for low suction pressure.
5. Variable head pressure valve. 5. Check valve setting.
High suction pressure 1. Excessive load. 1. Reduce load or add additional equipment.
At every six month interval, or sooner if local conditions cause clogging
or fouling of air passages through the nned surface, the following
items should be checked.
1) Visually inspect unit
• Look for signs of corrosion on ns, cabinet, copper tubing and solder joints.
• Look for excessive or unusual vibration for fan blades
or sheet metal panels when in operation. Identify fan cell(s) causing vibration and check motor and blade carefully.
• Look for oil stains on headers, return bends, and coil ns. Check any suspect areas with an electronic leak detector.
• Check drain pan to insure that drain is clear of debris, obstructions or ice buildup and is free draining.
2) Clean evaporator coil and blades
• Periodic cleaning can be accomplished by using a brush,
pressurized water or a commercially available evaporator
coil cleaner or mild detergent. Never use an acid
based cleaner. Follow label directions for appropriate
use. Be sure the product you use is approved for use in
your particular application.
• Flush and rinse coil until no residue remains.
• Pay close attention to drain pan, drain line and trap.
3) Check the operation of all fans and ensure airow is
unobstructed
• Check that each fan rotates freely and quietly. Replace
any fan motor that does not rotate smoothly or makes an
unusual noise.
• Check all fan set screws and tighten if needed.
• Check all fan blades for signs of stress or wear. Replace any blades that are worn, cracked or bent.
Air Cooled Condensing Units
Quarterly
1) Visually inspect unit
• Look for signs of oil stains on interconnection piping and
condenser coil. Pay close attention to areas around
solder joints, building penetrations and pipe clamps.
Check any suspect areas with an electronic leak detector.
Repair any leaks found and add refrigerant as needed.
• Check condition of moisture indicator/sightglass in the
sight glass if so equipped. Replace liquid line drier if there
is indication of slight presence of moisture. Replace
refrigerant, oil and drier if moisture concentration is
indicated to be high.
• Check moisture indicator/sightglass for ash gas. If found
check entire system for refrigerant leaks and add
refrigerant as needed after repairing any leaks.
• Check compressor sightglass (if equipped) for
proper oil level.
• Check condition of condenser. Look for accumulation
of dirt and debris (clean as required).
• Check for unusual noise or vibration. Take corrective
action as required.
• Inspect wiring for signs of wear or discoloration and
repair if needed.
• Check and tighten all are connections.
Semi-Annually
• Verify that all fan motors are securely fastened to the
motor rail.
• Lubricate motors if applicable.
4) Inspect electrical wiring and components
• Visually inspect all wiring for wear, kinks, bare areas and
discoloration. Replace any wiring found to be damaged.
• Verify that all electrical and ground connections are secure, tighten if necessary.
• Check operation/calibration of all fan cycle and defrost controls when used.
• Look for abnormal accumulation of ice patterns and adjust defrost cycles accordingly
• Compare actual defrost heater amp draw against unit data plate.
• Visually inspect heaters to ensure even surface contact
with the coil. If heaters have crept, decrease defrost
termination temperature and be sure you have even coil
frost patterns. Re-align heaters as needed.
• Check drain line heat tape for proper operation (supplied and installed by others).
5) Refrigeration Cycle
• Check unit cooler superheat and compare reading for
your specic application
• Visually inspect coil for even distribution
38
2) Repeat all quarterly inspection items.
3) Clean condenser coil and blades
• Periodic cleaning can be accomplished by using a brush,
pressurized water and a commercially available foam coil
cleaner. If foam cleaner is used, it should not be an acid
based cleaner. Follow label directions for appropriate use.
• Rinse until no residue remains.
4) Check operation of condenser fans
• Check that each fan rotates freely and quietly.
Replace any fan motor that does not rotate smoothly
or makes excessive noise.
• Check all fan blade set screws and tighten as required.
• Check all fan blades for signs of cracks, wear or stress.
Pay close attention to the hub and spider. Replace blades
as required.
• Verify that all motors are mounted securely.
• Lubricate motors if applicable. Do not lubricate
permanently sealed, ball bearing motors.
5) Inspect electrical wiring and components
• Verify that all electrical and ground connections are
secure, tighten as required.
• Check condition of compressor and heater contactors.
Commercial Refrigeration Parts
Look for discoloration and pitting. Replace as required.
• Check operation and calibration of all timers, relays
pressure controls and safety controls.
• Clean electrical cabinet. Look for signs of moisture, dirt,
debris, insects and wildlife. Take corrective action as
required.
• Verify operation of crankcase heater by measuring amp
draw.
6) Check refrigeration cycle
• Check suction, discharge and net oil pressure readings.
If abnormal take appropriate action.
• Check operation of demand cooling, liquid injection or
unloaders if so equipped.
• Check pressure drop across all lters and driers.
Replace as required.
• Verify that superheat at the compressor conforms to
specication. (30°F to 45°F)
• Check pressure and safety control settings and verify
proper operation.
Annually
2) Clean condenser coil and blades
• Periodic cleaning can be accomplished by using brush,
pressurized water or a commercially available coil cleaning
foam. If a foam cleaner is used, it should not be an acid based
cleaner. Follow label directions for appropriate use.
• Clear unnecessary trash and debris away from condenser.
3) Check the operation of all fans
• Check that each fan rotates freely and quietly. Replace
any fan motor that does not rotate smoothly or makes an
unusual noise.
• Check all fan set screws and tighten if needed.
• Check all fan blades for sighs of stress or wear. Replace any
blades that are worn, cracked or bent.
• Verify that all fan motors are securely fastened to the motor
rail.
• Lubricate motors if applicable (most Heatcraft condenser
motors are permanently sealed ball bearing type and do not
require lubrication)
4) Inspect electrical wiring and components
• Visually inspect all wiring for wear, kinks, bare areas and
discoloration. Replace any wiring found to be damaged.
7) In addition to quarterly and semiannual maintenance
checks, submit an oil sample for analysis
• Look for high concentrations of acid or moisture. Change
oil and driers until test results read normal.
• Investigate source of high metal concentrations, which
normally are due to abnormal bearing wear. Look for
liquid refrigerant in the crankcase, low oil pressure or low
superheat as a possible source.
8) Inspect suction accumulator (if equipped)
• If the accumulator is insulated remove insulation and
inspect for leaks and corrosion.
• Pay close attention to all copper to steel brazed
connections
• Wire brush all corroded areas and peeling paint.
• Apply an anticorrosion primer and paint as required.
Re-insulate if applicable.
Air Cooled Condensers and Fluid Coolers
At every six month interval, or sooner if local conditions cause
clogging or fouling of air passages through the nned surface, the
following items should be checked.
1) Visually inspect unit
• Look for signs of corrosion on ns, cabinet, copper tubing
and solder joints.
• Look for excessive or unusual vibration for fan blades or
sheet metal panels when in operation. Identify fan cell(s)
causing vibration and check motor and blade carefully.
• Look for oil stains on headers, return bends, and coil ns.
Check any suspect areas with an electronic leak detector.
• Verify that all electrical and ground connections are secure,
tighten if necessary.
• Check operation/calibration of all fan cycle controls when
used.
Replacement Parts by
InterLink is your link to a complete line of dependable and
certied commercial refrigeration parts, accessories and innovative
electronic controls for all Heatcraft Refrigeration Products (HRP)
brands - including Bohn, Larkin, Climate Control and Chandler.
At InterLink, we provide our wholesalers with a comprehensive
selection of product solutions and innovative technologies for the
installed customer base. And every product is built to ensure the
same high performance standards with which all HRP brands are
built — backed by a dedicated team to serve every customer need,
delivering at the best lead times in the industry.
Replacement parts should be obtained from your local InterLink
wholesaler. Replacement parts, which are covered under the
terms of the warranty statement on page 2 of this manual, will be
reimbursed for total part cost only. The original invoice from the
parts supplier must accompany all warranty claims for replacement
part reimbursement. Heatcraft Refrigeration Products reserves
the right to adjust the compensation amount paid on any parts
submitted for warranty reimbursement when a parts supplier's
original invoice is not provided with a claim. For more information,
call 800-686-7278 or visit www.interlinkparts.com.
39
Diagram 1. Typical Wiring Diagram for Single Evaporator with and without Defrost Timer.
Diagram 2. Typical Wiring Diagram for Single Evaporator with Defrost Timer Only.
40
Diagram 3. Typical Wiring Diagram for Multiple Evaporators with Defrost Timer Only.
Diagram 4. Typical Wiring Diagram for Single Evaporator / Single Phase Defrost and Evaporator Fan
Contactors.
41
Diagram 5. Typical Wiring Diagram for Single Evaporator Defrost and Evaporator Fan Contactors.
Diagram 6. Typical Wiring Diagram for Multiple Evaporators with Evaporator Fan Contactors but without
Heater Limit Defrost.
42
Diagram 7. Typical Wiring Diagram for Multiple Evaporators with Heater Limit Defrost and Evaporator
Fan Contactors.
Diagram 8. Typical Wiring Diagram for Multiple Evaporators Defrost and Evaporator Fan Contactors
with Unit Cooler Holdout Relay.
43
Diagram 9. Typical Wiring Diagram for Defrost Contactor with Evaporator Holdout Relay
without Heater Limit.
Diagram 10. Typical Wiring Diagram for Defrost Contactor with Evaporator Holdout Relay
with Heater Limit.
44
Diagram 11. Typical Wiring Diagram for Multiple Evaporators with Defrost Switches Connected in Series
and without Holdout Relays / Heater Limits.
45
Service Record
A permanent data sheet should be prepared on each refrigeration
system at an installation, with a copy for the owner and the original
for the installing contractor's les.
If another rm is to handle service and maintenance, additional copies
should be prepared as necessary.
System Reference Data
The following information should be lled out and signed by Refrigeration Installation Contractor at time of start-up.
Date System Installed: _____________________________________________________
Installer and Address: _____________________________________________________