WaterFurnace Envision2 NXW Chiller User Manual
NXW 10 to 50 Tons
Commercial Reversible Chiller - 60 Hz
Installation Information
Water Piping Connections
Electrical Data
Microprocessor Control
Startup Procedures
Preventive Maintenance
NXW Reversible Chiller Installation Manual
IM2502WN 06/14
Table of Contents
Model Nomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
General Installation Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
NXW REVERSIBLE CHILLER INSTALLATION MANUAL
Physical Dimensions
Physical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Field Connected Water Piping. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-11
Typical Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Water Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
System Cleaning and Flushing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Electrical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15-16
Wiring Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17-18
Field Wiring and Control Setup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-20
Control Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-22
Sequence of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Inputs and Outputs Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Networking Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Unit Display and Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25-26
Reference Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Legend . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Unit Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8
Operating Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Pressure Drop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Compressor / Thermistor Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Operating Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Heating and Cooling Cycle Analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
Troubleshooting Form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
Factory Start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35-37
Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
Replacement Fuse Chart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Service Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39-41
Revision Guide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
ENVISION2 NXW REVERSIBLE CHILLER INSTALLATION MANUAL
NXW 120 R 3 A E 8 N N
1-3 4-6 7 8 11 12 13
Vintage
Non-Standard Options
Future Option
Future Option
Controls
Rev.:
SS
14-15*16
9 10
Model Nomenclature
Model
NXW – Envision
Reversible Chiller
Unit Capacity (MBTUH)
120, 180, 240, 360, 600
Operation
R - Reversible
Voltage
3 – 208-230/60/3
4 – 460/60/3
5 – 575/60/3
8 – 380/60/3
Phase Protection
A – Non-Fused Disconnect, Phase Guard
B – Non-Fused Disconnect, IntelliStart®
C – Fused Disconnect, Phase Guard
D – Fused Disconnect, IntelliStart
Chassis
E – Enclosed
P – Enclosed with Pressure Gauges
Notes:
See electrical availability table for detailed offering by voltage
2
Series
* - Factory Use Only
SS - Standard
N – Future Use
N – Future Use
8 – FX10 without Communication,
with User Interface
9 – FX10 with Open N2 Communication
Card with User Interface
0 – FX10 with Lonworks Communication
Card with User Interface
3 – FX10 with BacNet Communication
Card with User Interface
14 February 2014D
Voltage Availability
Voltage
208-230/60/3
460/60/3
575/60/3
380/60/3
Legend:
NA = Not Available
120 180 240 360 600
•• ••
•• •• •• • •
•••••
••
NA NA
Model
• = Voltage available in this size
•• = Voltage and IntelliStart available in this size
NA
••
03/05/14
4
General Installation Information
ENVISION2 NXW REVERSIBLE CHILLER INSTALLATION MANUAL
Safety Considerations
Installing and servicing air conditioning and heating
equipment can be hazardous due to system pressure and
electrical components. Only trained and qualified service
personnel should install, repair or service heating and air
conditioning equipment. When working on heating and
air conditioning equipment, observe precautions in the
literature, tags and labels attached to the unit and other
safety precautions that may apply.
Follow all safety codes. Wear safety glasses and work
gloves. Use quenching cloth for brazing operations. Have
fire extinguisher available for all brazing operations.
NOTE: Before installing, check voltage of unit(s) to ensure
proper voltage.
WARNING: Before performing service or
maintenance operations on the system, turn off
main power switches to the unit. Electrical shock
could cause serious personal injury.
Application
Units are not intended for heating domestic (potable water)
by direct coupling. If used for this type of application, a
secondary heat exchanger must be used.
Unit Location
Provide sufficient room to make water and electrical
connections. If the unit is located in a confined space,
provisions must be made for unit servicing. Locate the
unit in an indoor area that allows easy removal of the
access panels and has enough space for service personnel
to perform maintenance or repair. These units are not
approved for outdoor installation and, therefore, must be
installed inside the structure being conditioned. Do not
locate units in areas subject to freezing conditions.
WARNING: Do not store or install units in
corrosive environments or in locations subject
to temperature or humidity extremes (e.g. attics,
garages, rooftops, etc.). Corrosive conditions and
high temperature or humidity can significantly
reduce performance, reliability, and service life.
WARNING: To avoid equipment damage and
possible voiding of warranty, be sure that
properly sized strainers are installed upstream
of both brazed plate heat exchangers to protect
them against particles in the fluid.
Moving and Storage
Move units in the normal “Up” orientation as indicated by
the labels on the unit packaging. When the equipment
is received, all items should be carefully checked against
the bill of lading to ensure that all crates and cartons
have been received in good condition. Examine units for
shipping damage, removing unit packaging if necessary
to properly inspect unit. Units in question should also
be internally inspected. If any damage is observed, the
carrier should make the proper notation on delivery receipt
acknowledging the damage. Units are to be stored in a
location that provides adequate protection from dirt, debris
and moisture.
WARNING: To avoid equipment damage, do not
leave the system filled in a building without heat
during cold weather, unless adequate freeze
protection levels of antifreeze are used. Heat
exchangers do not fully drain and will freeze
unless protected, causing permanent damage.
5
ENVISION2 NXW REVERSIBLE CHILLER INSTALLATION MANUAL
General Installation Information cont.
Mounting Units
Remove the unit from the wooden shipping skids (see physical dimensions). Units will be shipped with heavy duty rubber
grommets to reduce sound that can be transmitted through the floor via the frame (see isolator drawing). For additional
sound attenuation, use heavy duty spring isolation that can reduce sound levels by 3 dBA (see springs drawing).
Rubber Isolators RD2 RD3
Part
Number
99S502-01 RD2 Green 380 0.50 4
• Compatible with NXW120-180
Type
Color
Code
Max Load,
lbs
Deflection, in Qty
Part
Number
99S502-02 RD3 Green 750 0.50 4
• Compatible with NXW240-600
Type
Color
Code
Max Load,
lbs
Deflection, in Qty
Spring Isolators
Number
IS-325-01 NXW120-180 Brown 325 lbs 1.23" 264 lbs/in 1/2 x 3.5 4
IS-750-01 NXW240-600 Orange 750 lbs 1.06" 707 lbs/in 1/2 x 3.5 4
Compatible
With
Spring
Color
Rated
Capacity
Rated
Deflection
Isolator
Constant
Adjustment
Bolt
Qty
Unpacking the Unit
Remove the stretch warp and protective cardboard from the unit. Where applicable, remove the compressor shipping
brackets located at the base of each compressor. To do so, lift up the bottom of the compressor sound jacket and remove
the two bolts that hold the bracket .
6
Physical Dimensions
SERVICE PORTS
SOURCE
WATER OUT
ENVISION2 NXW REVERSIBLE CHILLER INSTALLATION MANUAL
EMERGENCY STOP SWITCH
DISCONNECT SWITCH
CONTROL BOX COVER
MAIN POWE R CONNECTION
SOURCE
WATER IN
LOAD
WATER IN
LOAD
WATER OUT
2.40
TO PORT
(SERVICE)
TOP
FX-10
CONTROLLER
DISPLAY
ACCESS DOOR
SIDE ACCESS
PANEL DOORS
VIBRATION PADS
NOTES:
1. DO NOT SCALE DRAWING.
FRONT
"B"
J
SOURCE
WATER OUT
SOURCE
WATER IN
REARSIDE
"G"
7.50
4.50
7.00
ELECTRICAL
HIGH VOLTAGE
ELECTRICAL
LOW VOLTAGE
4.50
4.00
"A"
LOAD
WATER IN
LOAD
WATER OUT
"C"
"H"
"F"
"E"
"D"
Model A B C D E F G H J
120-180
240-360
600
57.3
[1455]
64.2
[1631]
71.1
[1806]
24.1
[612]
24.1
[612]
24.0
[610]
42.5
[1080]
50.5
[1283]
58.5
[1486]
5.0
[127]
6.9
[175]
6.5
[165]
17.0
[432]
17.0
[432]
17.0
[432]
8.8
[224]
13.9
[353]
19.5
[495]
17.0
[432]
17.0
[432]
17.0
[432]
11.9
[302]
12.1
[307]
15.0
[381]
4.6
[117]
3.6
[91]
3.2
[81]
All dimensions in inches, [mm] 5/12/14
7
ENVISION2 NXW REVERSIBLE CHILLER INSTALLATION MANUAL
Physical Dimensions, cont.
T
S
T
DETAIL A
25.00
24.00
R
P
N
M
A
52.00
24.00
SHADED AREAS REPRESENT REQUIRED CLEARANCE
FOR SERVICE & MAINTENANCE OF EQUIPMENT.
K
L
Model K L M N P R S T*
120-180
240-360
600
57.0
[1448]
65.0
[1651]
70.0
[1778]
42.0
[1067]
42.0
[1067]
42.0
[1067]
63.1
[1603]
69.9
[1775]
76.8
[1951]
15.9
[404]
19.9
[505]
22.0
[559]
19.5
[495]
19.5
[495]
19.5
[495]
9.7
[246]
9.7
[246]
12.7
[323]
1.3
[33]
1.8
[46]
1.8
[46]
All dimensions in inches, [mm]
*T - Units shipped with groove pipe connection
2.0
[50.8]
2.0
[50.8]
2.5
[63.5]
5/12/14
8
Physical Data
ENVISION2 NXW REVERSIBLE CHILLER INSTALLATION MANUAL
Model Compressor
120
180
240
360
600
Weights shown in Pounds, [kg] 1/30/2014
* Refrigerant per circuit in Pounds, [kg]
Add 32 lbs [15 kg] for fluid weight when full. (120)
Add 48 lbs [22 kg] for fluid weight when full. (180)
Add 64 lbs [29 kg] for fluid weight when full. (240)
Add 110 lbs [50 kg] for fluid weight when full. (360)
Add 144 lbs [65 kg] for fluid weight when full. (600)
Scroll (2)
Scroll (2)
Scroll (2)
Scroll (2)
Scroll (2)
Refrigerant
Charge*
5.3 720 710
[2.4] [327] [323]
7.8 838 844
[3.5] [381] [384]
10.5 1130 1152
[4.8] [514] [524]
17.9 1320 1388
[8.1] [600] [631]
27.3 1748 1850
[12.4] [795] [841]
Total Weight
Shipping Installed
NOTE: See page 12 for minimum fluid volume guidelines.
9
ENVISION2 NXW REVERSIBLE CHILLER INSTALLATION MANUAL
Field Connected Water Piping
General
System piping should be kept as simple as possible to
minimize the pressure drop, but hand valves should be field
installed to facilitate unit servicing. The piping installation
should provide service personnel with the ability to measure
and/or monitor water temperatures and pressures.
Source and load fluid connections are provided with 2-inch
[50.8mm] Victaulic grooved nipples (see Figure 4). Each
nipple will also have a PT port installed for test and balance
purposes. It will be the installing contractor’s responsibility
to adequately support incoming piping to avoid damage to
the unit’s piping or heat exchangers. The water lines should
be routed so as not to interfere with access to the unit.
For any installation where the transmission of vibration
through the piping connections could cause unacceptable
noise levels in occupied spaces it is important to provide
adequate vibration damping. One method is to use the
optional Adapter Hose Kit (kit number TKC16S-4). This Kit
consists of four pieces of a braided stainless steel flexible
hose with a 2” Victaulic connection on one end and a 2”
MPT connection with pipe union on the other. Overall length
of each piece is 18”.
NOTE: Units are factory run-tested using propylene
glycol. Prior to connecting piping to unit, thoroughly flush
heat exchangers.
NOTE: The placement and connection of the water
circulating pump(s) must be taken into consideration prior
to designing the final water piping systems.
Closed Loop Tower/Boiler Systems
The water loop is usually maintained between 60°F [15.5°C]
and 90°F [32.2°C] for proper heating and cooling operation.
This is accomplished with a cooling tower and a boiler.
To reject excess heat from the condenser water loop, the
use of a closed-circuit evaporative cooler or an open type
cooling tower with a secondary heat exchanger between
the tower and the condenser water loop is recommended.
If an open type cooling tower is used without a secondary
heat exchanger, continuous chemical treatment and filtering
of the water must be performed to ensure the water is free
from damaging materials.
CAUTION: Water piping exposed to outside
temperature may be subject to freezing.
Open Loop Well Water Systems
Installation of an open loop system is not recommended
without using a secondary heat exchanger unless water
quality guidelines are met.
Before final connection to the unit, the supply and return
hose kits must be connected to each other, bypassing
the unit, and the system flushed to remove dirt, piping
chips and other foreign material. Normally, a combination
balancing and close-off (ball) valve is installed at the return,
and a rated gate or ball valve is installed at the supply. The
return valve can be adjusted to obtain the proper water
flow. The valves allow the unit to be removed for servicing.
The proper water flow must be delivered to each unit
whenever the unit heats or cools. The proper flow rate
cannot be accurately set without measuring the water
pressure drop through the refrigerant-to-water heat
exchanger. A 3 GPM flow rate per ton [0.054 LPS per kW]
of cooling capacity (2.25 GPM per ton [0.0404 LPS per
kW] minimum) is required.
CAUTION: Remove the plastic protective caps in the ends of each of the four water pipes on the heat
exchangers prior to piping connection. Failure to remove the caps will result in serious damage and could void
the warranty.
Earth Coupled Systems
All supply and return water piping should be insulated to
prevent excess condensation from forming on the water
lines. Ensure pumping system is capable of providing
adequate flow rate at the system pressure drop, 3.0 GPM
per ton [0.054 LPS per kW] (source side) is recommended.
Antifreeze in the loop is strongly recommended.
10
Envision2 NXW Typical Piping
Standard Piping
ENVISION2 NXW REVERSIBLE CHILLER INSTALLATION MANUAL
Field Supplied and InstalledFactory Installed
Pump
Water
Temperature
Sensors
Brazed Plate
Heat Exchanger
1/4” NPT
Pressure/Temperature
Port
Isolation Valves
Strainer
FS
Isolation Valve
Note: System piping should have drain ports to enable flushing and cleaning of heat exchangers. On systems utilizing
pumps with VFDs, an automatic flow control valve must be installed.
Pressure Regulated Piping
Field Supplied and InstalledFactory Installed
Isolation Valves
Pump
Pressure Actuated
Water Valve
From Load
To Load
Compressor
Discharge
Pressure
Strainer
FS
Isolation Valve
Water
Temperature
Sensors
Brazed Plate
Heat Exchanger
1/4” NPT
Pressure/Temperature
Port
Note: System piping should have drain ports to enable flushing and cleaning of heat exchangers. On systems utilizing
pumps with VFDs, an automatic flow control valve must be installed.
From Load
To Load
11
ENVISION2 NXW REVERSIBLE CHILLER INSTALLATION MANUAL
Envision2 NXW Application Data
1.0. Minimum Fluid Volume
A. Water-to-water heat pumps require a minimum amount
of source and load side fl uid volume to ensure accurate
and stable temperatures during system operation.
For normal air conditioning type applications, it is
recommended to use at least 7 gallons/ton.
B.
Applications that require more precise temperature
control or low loading will occur the minimum
fl uid volume shall be no less than 10 gallons/ton.
Installation of a buffer tank that will properly mix the
fl uid is recommended.
1.1. Water-to-Water Heat Pump Sizing
A. Heat pumps should be adequately sized for optimal
system effi ciency and run time. Oversizing by more
than 15% can diminish performance resulting in higher
power consumption, short cycling of compressors, and
unstable conditioning temperatures.
B. In applications where the minimum load is signifi cantly
less than the design condition, it is better to install 2
smaller heat pumps for load matching rather than a
single large heat pump.
1.2. Heat Pump Piping
A. Multiple heat pumps can be installed in series or
parallel confi gurations. The preferred system design is
to pipe the equipment in parallel due to its simplicity
and fl exibility. In parallel systems, the heat pump
equipment can vary in size as long as fl ow rate and
system volume are accounted for.
B. Piping equipment in series is not desired; however,
it can be done if proper guidelines are followed.
Always observe proper temperature and fl ow rate
requirements for each unit. Sometimes this method is
desired to achieve larger temperature differences.
1.3. Strainers
A. All brazed-plate heat exchangers shall have a
strainer within 8 ft of the water/brine inlet. It is highly
recommended to use a minimum of 60 mesh in order
to provide maximum fi ltration. In any case, the strainers
should never have a mesh size less than 20.
B. Failure to install proper stainers and perform regular
service can result in serious damage to the unit, and
cause degraded performance, reduced operating life
and failed compressors. Improper installation of the
unit (which includes not having proper strainers to
protect the heat exchangers) can also result in voiding
the warranty.
C. Strainers should be selected on the basis of acceptable
pressure drop, and not on pipe diameter. The strainers
selected should have a pressure drop at the nominal
fl ow rate of the units; low enough to be within the
pumping capacity of the pump being used.
1.4. Flow Sensing Devices
A. A fl ow switch or equivalent must be installed on the
evaporator for each unit to be installed. If the unit is to
operate as both modes (heating/cooling), a fl ow switch
is needed on both heat exchangers.
B. A differential pressure switch can be used in place of a
fl ow switch. The differential switch must be capable of
pressure range as indicated in the pressure drop tables.
1.5. Water Quality
A. General: Reversible chiller systems may be successfully
applied in a wide range of commercial and industrial
applications. It is the responsibility of the system
designer and installing contractor to ensure that
acceptable water quality is present and that all
applicable codes have been met in these installations.
B. Water Treatment: Do not use untreated or improperly
treated water. Equipment damage may occur. The
use of improperly treated or untreated water in this
equipment may result in scaling, erosion, corrosion,
algae or slime. The services of a qualifi ed water
treatment specialist should be engaged to determine
what treatment, if any, is required. The product
warranty specifi cally excludes liability for corrosion,
erosion or deterioration of equipment.
The heat exchangers in the units are 316 stainless steel
plates with copper brazing. The water piping in the
heat exchanger is steel. There may be other materials
in the building’s piping system that the designer may
need to take into consideration when deciding the
parameters of the water quality.
If an antifreeze or water treatment solution is to be
used, the designer should confi rm it does not have a
detrimental effect on the materials in the system.
C. Contaminated Water: In applications where the
water quality cannot be held to prescribed limits, the
use of a secondary or intermediate heat exchanger
is recommended to separate the unit from the
contaminated water.
The following table outlines the water quality
guidelines for unit heat exchangers. If these conditions
are exceeded, a secondary heat exchanger is required.
Failure to supply a secondary heat exchanger where
needed will result in a warranty exclusion for primary
heat exchanger corrosion or failure.
WARNING: Must have intermediate heat exchanger
when used in pool applications.
12
ENVISION2 NXW REVERSIBLE CHILLER INSTALLATION MANUAL
Envision2 NXW Application Data cont.
1.6. Insulation
A. Heat pumps are built with factory installed insulation
on any surface that may be subject to temperatures
below the room dew point.
Surface Condensation Chart
Room Ambient Condition
Normal (Max 85°F, 70% RH) 1/2" 3/4" 1"
Mild (Max 80°F, 50% RH) 1/8" 1/4" 1/2"
Severe (Max 90°F, 80% RH) 3/4" 1" 2"
Surface Temperature
50°F 35°F 0°F
Water Quality Guidelines
Material 316 Stainless Steel
pH Acidity/Alkalinity
Scaling
Corrosion
Iron Fouling
(Biological Growth)
Erosion
NOTES: Grains = ppm divided by 17
mg/L is equivalent to ppm
Calcium and
Magnesium Carbonate
Hydrogen Sulfide Less than 1 ppm
Sulfates Less than 200 ppm
Chlorine Less than 0.5 ppm
Chlorides Less than 300 ppm
Carbon Dioxide 10 - 50 ppm
Ammonia Less than 20 ppm
Ammonia Chloride Less than 0.5 ppm
Ammonia Nitrate Less than 0.5 ppm
Ammonia Hydroxide Less than 0.5 ppm
Ammonia Sulfate Less than 0.5 ppm
Total Dissolved Solids (TDS) 1000 - 1500 ppm
LSI Index +0.5 to -0.5
2
Iron, FE
Bacterial Iron Potential
+ (Ferrous)
Iron Oxide
Suspended Solids
Threshold Velocity
(Fresh Water)
(Total Hardness)
less than 350 ppm
< 0.2 ppm
Less than 1 ppm, above this
level deposition will occur
Less than 10 ppm and filtered
for max. of 600 micron size
< 6 ft/sec
7 - 9
1.7. Brine Applications
A. Applications where the leaving fl uid temperature goes
below 40°F a suitable brine solution must be used.
Failure to do so can cause immediate damage to the
system. The brine must be approved for use with heat
exchangers. Automotive antifreeze solutions are not
suitable for use in brazed plate heat exchangers.
B.
The freeze detection must be adjusted appropriately
for brine applications. The brine solution
concentration should be at least 15°F below the
lowest leaving fl uid temperature.
2/22/12
13
ENVISION2 NXW REVERSIBLE CHILLER INSTALLATION MANUAL
System Cleaning and Flushing
Cleaning and Flushing
Prior to start up of any heat pump, the water circulating
system must be cleaned and flushed of all dirt and debris.
If the system is equipped with water shutoff valves, the
supply and return runouts must be connected together
at each unit location (This will prevent the introduction of
dirt into the unit, see Flushing with Water Shutoff Valve
Equipped Systems illustration). The system should be filled
at the water make-up connection with all air vents open.
After filling, vents should be closed.
Flushing with Water Shutoff Valve Equipped Systems
Return Runout
Supply Runout
Mains
Rubber Hose
Runouts Initially
Connected Together
The contractor should start the main circulator with the
pressure reducing valve makeup open. Vents should be
checked in sequence to bleed off any trapped air and to
verify circulation through all components of the system.
As water circulates through the system, the contractor
should check and repair any leaks found in the piping
system. Drain(s) at the lowest point(s) in the system should
be opened for initial flush and blowdown, making sure
water fill valves are set at the same rate. Check the pressure
gauge at the pump suction and manually adjust the makeup water valve to hold the same positive pressure both
before and after opening the drain valves. Flushing should
continue for at least two hours, or longer if required, until
drain water is clean and clear.
The supplemental heater and/or circulator pump, if used,
should be shut off. All drains and vents should be opened
to completely drain the system. Short-circuited supply and
return runouts should now be connected to the unit supply
and return connections.
Refill the system with clean water. Test the system water
for acidity and treat as required to leave the water slightly
alkaline (pH 7.5 to 8.5). The specified percentage of
antifreeze may also be added at this time. Use commercial
grade antifreeze designed for HVAC systems only.
Environol™ brand antifreeze is recommended.
Once the system has been filled with clean water and
antifreeze (if used), precautions should be taken to protect
the system from dirty water conditions. Dirty water will
result in system-wide degradation of performance, and
solids may clog valves, strainers, flow regulators, etc.
Additionally, the heat exchanger may become clogged
which reduces compressor service life and can cause
premature unit failure.
In boiler/tower application, set the loop control panel
set points to desired temperatures. Supply power to all
motors and start the circulating pumps. After full flow has
been established through all components including the
heat rejector (regardless of season), air vented and loop
temperatures stabilized, each of the units will be ready for
check, test and start up and for air and water balancing.
Ground Source Loop System Checkout
Once piping is completed between the unit pumping
system and ground loop, final purging and charging of
the loop is needed. A high pressure pump is needed to
achieve adequate flow velocity in the loop to purge air
and dirt particles from the loop itself. Antifreeze solution
is used in most areas to prevent freezing. Flush the
system adequately to remove as much air as possible;
then pressurize the loop to a static pressure of 40-50
PSI (summer) or 50-75 PSI (winter). This is normally
adequate for good system operation. Loop static pressure
may decrease soon after initial installation, due to pipe
expansion and loop temperature change. Running the
unit for at least 30 minutes after the system has been
completely purged of air will allow for the “break-in”
period. It may be necessary to adjust static loop pressure
(by adding water) after the unit has run for the first time.
Loop static pressure will also fluctuate with the seasons.
Pressures will be higher in the winter months than during
the cooling season. This fluctuation is normal and should be
considered when charging the system initially.
14
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