Owner’s Manual &
Installation Instructions
Zone Comfort
hot water air handler
and zoned distribution system
with iStat6 electronic controller for 2 to 4 zones
Vortex Source Systems
45 Cowansview Rd.
Cambridge, Ontario
N1R 7L2
Phone: 888-781-8151
Fax: 888-670-2544
info@vortexsource.com
www.vortexsource.com
Table of Contents
CHECKLIST FOR THE INSTALLER .................................................................................................................. 3
TYPICAL PLUMBING CONNECTIONS ............................................................................................................. 4
ELECTRICAL WIRING DIAGRAM – 4 ZONE COMPLETE................................................................................. 5
ELECTRICAL WIRING DIAGRAM – 4 ZONE BASE ........................................................................................... 7
EQUIPMENT SPECIFICATIONS AND SIZING TABLES ................................................................................ 8
INTRODUCTION .................................................................................................................................................... 9
HOW IT WORKS..................................................................................................................................................... 9
Zone One ................................................................................................................................................................. 9
Off ......................................................................................................................................................................... 10
Heating .................................................................................................................................................................. 10
Cooling.................................................................................................................................................................. 10
Continuous Fan ..................................................................................................................................................... 10
Features ................................................................................................................................................................. 10
Evaporator Coil Freeze Protection........................................................................................................................ 10
PRODUCT DESCRIPTION .................................................................................................................................. 10
Cabinet .................................................................................................................................................................. 11
Heating coils ......................................................................................................................................................... 11
Fan and Motor ....................................................................................................................................................... 11
Circulating pump .................................................................................................................................................. 11
Check Valve .......................................................................................................................................................... 11
EQUIPMENT SIZING AND SELECTION ......................................................................................................... 12
Procedure .............................................................................................................................................................. 12
Heat Loss / Heat Gain ........................................................................................................................................... 12
Air Handler Selection ........................................................................................................................................... 12
Define Zones ......................................................................................................................................................... 12
INSTALLATION ................................................................................................................................................... 13
Air Handler Mounting .......................................................................................................................................... 13
Ductwork .............................................................................................................................................................. 13
Risk of Freezing .................................................................................................................................................... 14
ELECTRICAL ........................................................................................................................................................ 14
Thermostat ............................................................................................................................................................ 14
Heat Anticipator Setting ....................................................................................................................................... 15
Dehumidistat ......................................................................................................................................................... 15
START-UP PROCEDURE .................................................................................................................................... 16
SERVICE AND MAINTENANCE........................................................................................................................ 16
Filter ...................................................................................................................................................................... 16
Duct cleaning ........................................................................................................................................................ 16
Coils ...................................................................................................................................................................... 16
Air conditioning coil ............................................................................................................................................. 16
Fan and motor ....................................................................................................................................................... 16
Pump ..................................................................................................................................................................... 17
TROUBLESHOOTING ......................................................................................................................................... 17
Page 2 ZC-KI6-VSS1707
CHECKLIST FOR THE INSTALLER
A Quick Check List
Are the water connections to the water heater oriented in a way to avoid
trapping air in the heating circuit? (see diagram on next page)
Is the purge valve installed on the return water line from the air handler
upstream from the isolation valve?
Is the air handler hung and isolated to avoid transmitting vibration through
framing and duct work?
Are the isolation valves full-port? Restrictive valves will limit performance.
Is outdoor cooling unit contactor wired according to the wiring diagram?
Are Thermostat connections correct, including cooling and continuous run
connections? Do they operate their intended zone?
Have the packing materials been removed from the blower?
Is there an installation manual and controls user manual for the home owner ?
Is the unit accessible? Are there clearances for service and component
replacement?
Is the return duct/drop acoustically lined ? (recommend lining at least 6 ft. of
the return duct/drop)
Is the filter cover in place? Is a clean filter in place?
Has the electronic controller been properly configured as per instructions in the
controls user manual?
Page 3 ZC-KI6-VSS1707
TYPICAL PLUMBING CONNECTIONS
Page 4 ZC-KI6-VSS1707
EQUIPMENT SPECIFICATIONS AND SIZING TABLES
REFER TO Small-D design Guide for additional duct sizing options.
TABLE 1 - Air Handler Selection Table
Model
ZC24L
ZCT24L
Min. 4” Branches per Zone 6 8 9 11 12 15 15
Min. 14”x8” Return Air Grilles 5 7 8 8 9 10 11
Heating Capacity1
(Btu/h)@130ºF
Heating Capacity1
(Btu/h)@140ºF
Heating Capacity1
(Btu/h)@160ºF
Heating Capacity1
(Btu/h)@180ºF
Air flow rate at full heating
(cfm)
Max. Ext. Static Pressure (“wc)
50,000 58,000 65,000 65,000 69,000 73,000 91,000
54,000 63,000 70,000 70,000 75,000 80,000
66,000 80,000 90,000 90,000
81,000 99,000 110,000
1000 1200 1400 1400 1600 1800 2000
1.3 0.6 1.1 1.1 1.2 0.7 0.8
ZC30L
ZCT30L
ZC36L
ZCT36L
ZC42L
ZCT42L
110,000 117,000 125,000 164,000
ZC48L
ZCT48L
97,000 103,000 135,000
ZC60L
ZCT60L
ZC100
106,000
USGPM Heating 6 6 6 6 6 6 10
Cooling Capacity
Blower Motor Full Load
(Amps)
2,3
(Tons) 2.0 2.5 3.0 3.5 4.0 5.0 5.0
5.5 5.5 7.7 7.7 9.6 9.6 9.6
Circulator Full Load (Amps) 0.8 0.8 0.8 0.8 0.8 0.8 1.4
Cabinet Width (in.) 22 22 22 22 22 22 22
Cabinet Depth (in.) 25 25 25 25 25 25 25
Cabinet Height (in.)
(Regular ZC)
Cabinet Height (in.)
(Tall ZCT)
44 44 44 44 44 44 65
65 65 65 65 65 65 N/A
Supply Air ( per Zone) 8”Φ 8”Φ 8”Φ 10”Φ 10”Φ 10”Φ 10”Φ
Return air (in.) 18x23 18x23 18x23 18x23 18x23 18x23 18x23
Supply and Return Water
Connections (in.)
Weight-air handler only
(pounds)
1. capacity based on 70ºF return air, high speed and 12.5 feet length per branch at 4”
diameter. Two 3” branches = one 4”, two 4” = one 6”. Do not exceed grille rating. Higher
static pressure/reduced heating capacity available at lower airflow.
3/4 3/4 3/4 3/4 3/4 3/4 1
150 150 155 170 175 175 200
2. Regular ZC requires external cooling coil (extra) in the return air duct.
3. Tall ZCT can use cooling A-coil supplied by others. Cabinet opening is 20W x 24D x 21H.
Page 8 ZC-KI6_VSS1709
INTRODUCTION
The Zone Comfort system is a heating
and cooling system that enhances
comfort and improves efficiency by giving
more control over the distribution of
conditioned air. Homeowners enjoy
many benefits such as healthy indoor air,
comfortable basements and cool
summer evenings. Multiple thermostats
provide the means to zone the home by
section or level in order to gain more
control. This will virtually eliminate over
or under conditioned spaces as is
common in a lot of homes today.
The Zone Comfort system is designed
for use in hydronic (boiler) systems or
combination space and water heating
systems (Combo Systems). Combo
heating systems use the home’s water
heater to provide both the space heating
and domestic hot water, eliminating the
need for a furnace. The equipment can
be configured for heating only, heating
and cooling or cooling only applications.
Contact Vortex for Zone Comfort
systems to be connected to a heat pump.
The Zone Comfort duct system can be
much smaller than conventional ducting
making it ideal for retrofit applications or
where a conventional duct system would
result in unsightly bulkheads and wasted
space.
When used as the warm air distributor of
a boiler heating system the Zone
Comfort air system can provide
warmer more comfortable air
temperature than a gas furnace with less
noise and much smaller duct
requirements. This is ideal for large
custom homes where a premium heating
product is required that is quiet,
comfortable and out of sight.
Controls usage and settings are covered
in a separate document.
HOW IT WORKS
The key to the Zone Comfort system is
the level of comfort and efficiency
provided by the unique control system.
Zone dampers in the air handler operate
to increase or decrease the capacity in
each zone of the house as needed.
Heating and cooling air flow for each
zone can be set by the installer to
customize every installation.
Cooling mode uses a fixed or automatic
strategy to maximize homeowner
comfort. In auto mode, blower speed is
carefully controlled to optimize
dehumidification. When cooling demand
is low (determined based on the number
of zones calling or on the measured
supply air temperature) the blower runs a
little slower. The air has more residence
time in the evaporator coil. This results
in removing more moisture from the air,
thus maintaining the humidity in an
optimum range.
Zone One
The primary or master or zone one tells
the air handler whether it is heating
season or cooling season or if
continuous air circulation is desired. Any
zone can be zone one but it is typically
Page 9 ZC-KI6-VSS1709
the main area of the building (living
area).
Additional zones act as slaves to the
primary zone. The primary zone must
call for heating or cooling at least
once (a short, 5 second call is
adequate) at the beginning of the
season to tell the Zone Comfort air
handler that it is in heating mode or
cooling mode. The switch on the
primary thermostat is not enough!
Until this happens, a call on zone two,
three or four is ignored.
Off
All zone dampers are open if there is no
call for heating or cooling or power is off.
Heating
When a thermostat calls for heating, the
internal pump starts and the boiler is
activated (if connected to TT). The zone
damper for any zone not requiring heat
closes. The fan will gradually ramp up to
the programmed speed for the given
zone.
Cooling
When a thermostat calls for cooling, the
outdoor air conditioning (AC) condenser
is activated. The zone damper for any
zone not requiring cooling closes. Fan
speed can be controlled based on
number of zones calling and their
programmed cooling loads, or on
measured supply air temperature. Two-
stage air conditioners are strongly
recommended as a means of
improving efficiency, lowering fan
speed for single zone calls and more
closely matching AC output to the
home’s cooling requirements.
Continuous Fan
When the thermostat fan switch for the
primary zone is set to continuous fan, the
fan will run at the set speed for all zones.
When there is a call for heating or
cooling, the normal heating or cooling
speed will over-ride the continuous fan
setting. Zones not requiring heating or
cooling will close. Once the thermostat is
satisfied, continuous fan speed will
resume.
Features
Vortex air handlers offer many unique
features that set them apart from the
competition:
Soft Start is a feature that starts the fan
slowly and quietly rather than a large
“thump” common in some furnaces and
air handlers.
Evaporator Coil Freeze Protection
If the evaporator coil air temperature
drops outside of the expected operating
range this indicates a potential
evaporator coil freeze condition. Coil
freezing can lead to slugging (liquid
refrigerant going back to the compressor)
which will damage the compressor. All
Zone Comforts come equipped with a
sensor and controller which will respond
by shutting off the outdoor cooling unit to
allow the system to warm up. Note that
this freeze condition is not normal and
may indicate blocked ducts, dirty filter or
an over-sized cooling unit.
PRODUCT DESCRIPTION
Page 10 ZC-KI6_VSS1709
Cabinet
All cabinets have a tough, durable low
maintenance painted finish.
Cabinet dimensions are designed to
provide maximum installation flexibility.
Refer to installation requirements for
more details.
Heating coils
All heating coils are potable water grade
copper suitable for use in plumbing
systems. No lead solder is used in any
component construction. All coils and
internal piping conform to ASTM B68 or
ASTM B88 standards.
High-density aluminum fins provide
maximum heat transfer for small coil
surface.
Fan and Motor
All fans are wide body dynamically
balanced for extra quiet operation. Multidirectional sleeve bearing motors allow
mounting in any direction for maximum
installation flexibility.
Circulating pump
The circulating pump is matched for
maximum performance. Air handlers
come with internally mounted pumps for
ease of installation. Air handlers can be
special ordered with external, field
installed pumps, when it is desirable to
locate the circulator below the air
handler, such as in attic installations.
Check Valve
Check valves serve two purposes:
• protect against back-flow of water
to avoid short circuiting around the
water heater during domestic
water use.
• protect against thermal siphoning.
Thermal siphoning is flow of water
through the space heating circuit while
the circulating pump is not operating, due
to hot water rising by natural convection.
During summer months this will cause
overheating, interfere with air
conditioning and waste energy.
All Vortex air systems come supplied
with spring-loaded check valves. The
check valve may be integral with the
pump. These check-valves have been
tested and proven to resist thermal
siphoning for installations where the air
handler elevation does not exceed the
distance above the water heater shown
in the table below.
valve size Maximum elevation
1/2”(12mm) 25 feet(8 metres)
3/4”(20mm) 50 feet(15 metres)
Page 11 ZC-KI6-VSS1709
EQUIPMENT SIZING AND SELECTION
Procedure
1. Conduct a complete heat loss / heat
gain calculation.
2. Determine inlet water temperature
3. Select Air Handler
4. Determine zones within the space.
Three is typical but it can be 2 or 4.
5. Select # outlets per room
6. Determine Duct Layout
Heat Loss / Heat Gain
Room by room calculations need to be
completed using HRAI, ASHRAE, or
another approved sizing methods.
Air Handler Selection
The selected air handler must be sized
according to the following rules:
a) Heating capacity must be between
100% and 140% of the heat loss.
(110% to 140% for combo systems
130°F water temp)
b) Cooling capacity must be between
75-100% of the heat gain. Note that
slightly under-sizing the cooling
equipment improves efficiency and
provides better humidity control.
Zoning ensures the space will be
comfortable even on the hottest days.
When using a boiler system, select a
boiler with an output that meets or
exceeds the heat loss of the space being
heated. If the boiler is serving additional
loads, size the boiler to meet the total
combined load.
For combo heating systems, use an
approved sizing method such as the
Unified Combo Guidelines published by
HRAI.
Define Zones
The space served by the air handler
should be divided up into zones. Three is
typical. Each of these zones is to be
served by a single main duct by the air
handler. Zones can represent areas such
as the basement, main floor and second
floor. In some applications, it may be
desirable to divide the area into east
facing, west facing and basement zones
depending on solar gain. Zoning based
on usage is also acceptable: office, living
and sleeping areas for example.
Page 12 ZC-KI6-VSS1709
INSTALLATION
The installer must adhere strictly to all
local and national code requirements
pertaining to the installation of this
equipment. Detailed instructions are
shipped with all accessory items and
should be followed closely.
Air Handler Mounting
The Zone Control air handler can be
installed in any direction. Some
precautions must be observed for some
of the possible mounting positions. For
installations where the access door faces
up or down, select an air handler with an
external pump to avoid the pump being
mounted with its shaft vertical. The pump
shaft must be mounted horizontally to
avoid premature failure.
The air handler can be hung by securing
straps through any of the existing screw
holes in the cabinet. When the existing
screw is too short for securing a
mounting strap, a longer screw can be
used provided care is taken not to
damage any internal components. When
fastening straps using screws other than
those supplied with the cabinet, special
care should be taken in the vicinity of the
coil to avoid tube puncture.
The cabinet is designed so that the
return air can be located on either side of
the cabinet, through the bottom of the
cabinet, or from the back. Position the
filter rack so that the filter is readily
accessible.
Install the air handler with the door firmly
screwed in place to make sure the
cabinet remains square.
Provide at least 2 feet (0.75 metres) of
service clearance in front of the access
panel of the air handler. Zero clearance
is acceptable on all other faces.
Ductwork
Zone Comfort air handlers are suitable
for conventional ductwork or small D™
systems.
Duct selection for each zone should be
based upon ease of installing ductwork.
Final assignment of zones can be done
by changing zone damper wires on the
terminal strip in the top section of the air
handler. Duct connections at the air
handler should be labeled for future
reference (eg. bsmt, main, upstairs).
Supply trunks may be square or round.
SEAL all joints and seams with metal
tape or sealing compound. Locate outlets
at least 6 inches from outside walls or
window coverings.
For small D™, one 25 ft length of flex
duct will provide two 12.5ft branches.
Use only Class 1 flex duct or duct
connector. All vertical portions of branch
connections (such as to high wall grilles)
must be rigid duct. Flexible duct may only
be used in horizontal portions of the
branch.
Return air plenum should be the same
cross sectional area as the air handler
return air opening. In vertical
installations, a conventional return air
drop and elbow is acceptable.
Ductwork installed in unheated spaces
such as attics must be installed between
the insulation and the heated space.
Page 13 ZC-KI6_VSS1709
Provide at least R-12 of insulation above
ducts. If cooling is required, the branch
and trunk lines must be insulated and
sealed with a vapour barrier prior to
applying house insulation.
Risk of Freezing
Steps must be taken to prevent the
hot water coil from freezing. Coils
that have failed due to freezing and
damage caused by frozen coils are
not covered under warranty.
HRV and Fresh air connections
If a fresh air duct is required, make
connection to return air plenum at least
18 inches from filter. Insulate all fresh air
ducts.
Fresh air and HRV connections to
ductwork can pose a risk of dumping
cold air into ductwork during periods of
stand-by or continuous run. Calculate
mixed air stream temperatures and
provide interlock controls to prevent
freezing conditions.
Evaporator coils
The Zone Comfort is designed to provide
acceptable airflow for cooling even if only
one zone is operating in cooling mode.
However, a small, single-zone operating
for a long time or abnormal conditions
such as plugged filter can pose the risk
of freezing. All Zone Comforts with
electronic controls include a temperature
sensor that will detect a near freezing
condition and will interrupt the outdoor air
conditioner until it warms up. (Refer to
Controls User Manual).
Attic and crawl spaces
Air handlers may be located in areas
subject to freezing conditions. It is
necessary to protect the hot water coil
from freezing. Contact Vortex for freeze
protection options.
ELECTRICAL
Warning! - Make sure unit is properly
grounded. Locate air handler on a
separate electric circuit.
All air handlers operate on
115VAC/1ph/60hz line voltage, less than
12 Amps. All control circuits are low
voltage, either 24VAC or 0-10VDC.
Thermostat
The Zone Comfort air handlers are
compatible with most thermostats. Some
electronic thermostats (primarily “power
robbing” types) require the addition of a
resistor between the W & C terminals
and the Y & C terminals. This is usually
covered in the thermostat instruction
manual. A 1,000 ohm, 5 watt resistor on
each of the W and Y terminals will
usually be enough to drain the current
required to power the thermostat. Some
thermostats will need 250 ohm, 10 watt
resistors on each of the W and Y
terminals.
Any zone with cooling will require a
heat/cool thermostat. The Zone
Comfort air handler is compatible with
all standard setback thermostats.
Setback thermostats can be used to
achieve greater energy savings. Twostage thermostats are not required with
two-stage air conditioning. The Zone
Comfort™ will determine when to bring
on second stage cooling based on total
building demand.
Page 14 ZC-KI6_VSS1709
Heat Anticipator Setting
For optimum comfort the anticipator
setting should be set to provide
approximately 4 cycles per hour
Typical Heat
Anticipator Setting
0.25 amps
Note: The wires from each thermostat
should be labeled for future reference.
Label suggestions are: 1, 2, 3, 4 or
bsmt., main, upstairs. If labels are not
available, use one, two or three “stripes”
of tape.
Thermostat wires should be connected to
terminal strip inside the air handler.
Each zone has its own terminal for R.
W1, W2, and W3 represent heating for
zone 1, 2, 3, 4. Y1, Y2, Y3, Y4
represents cooling for zone 1, 2, 3, 4.
Only G from the primary thermostat
should be connected to the air handler.
Thermostats with a C terminal should be
connected.
Dehumidistat
Dehumidistats are not necessary, as
dehumidification may be achieved
through Zone Comfort’s automatic
control of cooling speed. Refer to
Controls User Manual for more details.
Zone Selection & Set-up
Zone 1:
Any zone can be the primary zone or
Zone One. However, it is strongly
recommended that this be the main zone
to be heated and cooled. In a home, this
is typically the main living area. This
thermostat is the only one that is used to
select continuous fan operation. It also
plays a critical role in telling the air
handler whether to be in heating mode or
cooling mode.
When initially started or during seasonal
changeover from heating/cooling, this
thermostat must call at least once before
the air handler control will properly
recognize a heating or cooling call from
the other zones.
Other Zones (2,3,4):
These zones are the same and any area
to be heated and/or cooled can be
selected as zone 2, 3 or 4.
Duct/Zone Connections to Air
Handler:
The 6”/8”/10” round duct connections on
top of the air handler are labeled zone 1,
2, 3 and 4. The colours yellow, orange,
blue and violet correspond to the wire
colours connecting them to the air
handler control. NOTE: THESE ARE
FACTORY DEFAULT ZONE
SELECTIONS AND THE
INSTALLATING CONTRACTOR CAN
REASSIGN ANY DUCT CONNECTIONS
ON TOP OF THE AIR HANDLER ZONE
ONE, TWO, THREE OR FOUR.
To change duct connection assignments,
change the wires connected to the
terminal block. The output is as follows:
thermostat #1 = Yellow, #2 = Orange, #3
= Blue, #4 = Violet. The factory default is
for the same coloured wires connected to
the dampers and labeled zones 1, 2, 3
and 4. The colour labels on top of the air
handler correspond to the wire colours to
the damper. For example, to reassign
the blue duct connection to thermostat
#1, and yellow duct connection to
thermostat #3, reverse the yellow and
blue wires on the terminal block.
Page 15 ZC-KI6_VSS1709
START-UP PROCEDURE
Do not start the air handler or water
heater until ALL air has been purged!
1. Fill the boiler loop or water heater
with water, but do not start it.
2. Purge all air from the boiler heating or
domestic water system.
3. Purge all air from the space-heating
loop by closing the isolation valve on
the return leg of the loop and open
the drain to purge air. Open the return
leg isolation valve and then close the
drain valve.
4. Start the boiler or water heater
according to the manufacturer’s
instructions. Set the design water
temperature and wait for the system
to shut off. You can check that the
water heater is set properly during the
warm up by running a small amount
of water into a glass in a sink while
the water heater is warming up. Using
a thermometer measure the
temperature of the water as soon as
the water heater burner shuts off. If
the set-point temperature is too low or
is above 140F/60C, reset the tank
control, run water until the burner
starts again and repeat the
measurement.
5. Turn on the power to the air handler
and set up the electronic controller as
per instructions in the Controls User
Manual. This is important to ensure
that the correct airflows are used for
the equipment as installed.
6. Set the room thermostat for heat to
energize the fan and pump. If a
gurgling sound is present, it should
subside within one minute. If noise is
still present after one minute, repeat
step 3 to purge air as necessary.
7. Check pipes for heating to make sure
there is flow and feel the pump motor
to see if it is running hot.
SERVICE AND MAINTENANCE
Filter
The filter should be inspected monthly
and replaced as required.
Duct cleaning
If proper filter maintenance is adhered to,
duct cleaning will not be required for the
life of the equipment.
Coils
Air conditioning and heating coils should
not require cleaning if the filter
maintenance schedule is adhered to. If a
filter is damaged or collapses from
Page 16 ZC-KI6-VSS1709
plugging, dust may foul the coils. If this
happens, replace the filter and carefully
vacuum the heating coil. The fan may
need to be removed to gain access to
the face of the heating coil.
Air conditioning coil
At the start of each cooling season,
check the drain connection to the cooling
coil to ensure it is free of debris. If a
plugged air conditioning coil is
suspected, call a service technician for
testing and cleaning
Fan and motor
Check fan for dust once a year. If dirty,
vacuum to remove dust. Keeping the fan
blades clean will reduce noise and
improve the capacity and efficiency of
the heating system.
Pump
The circulating pump is water lubricated
TROUBLESHOOTING
Also refer to the controls
troubleshooting guide.
Thermostat Call Error
Thermostat calls are displayed on the
8_gang relay board. ANY valid heating
call will be illuminated as well as the
pump relay LED. Likewise, ANY valid
cooling call will illuminate as well as
AIR_COND LED.
If both Z1_HEAT and Z2_COOL are on
at the same time, there is a thermostat
error. Check wiring and that the
thermostat is set as a regular heat/cool
and not heat pump mode.
Calls on thermostats two, three and four
are ignored if the air handler system
(through zone one) has not switched
over to the same season. For example,
if zone one is in heating mode, any
cooling call on zones 2, 3 or 4 are
ignored and Z2_CALL, Z3_CALL and
Z4_CALL will not illuminate. If the air
handler does not run when zones two,
three or four are calling, activate the
primary zone briefly ( at least 5 seconds)
to set the air handler in heating or
cooling mode. Note that some
thermostats have a delay (typically five
minutes) before they will start the air
handler in cooling the first time.
and should require no regular
maintenance. A cycle timer feature is
available on the Vortex control to
exercise the pump even during
prolonged periods of no heat to avoid
seizing from long idle periods.
Relay failure – a 24vac DPDT relay acts
as a latching relay for zones 2 and 3 to
prevent incorrect thermostat calls from
reaching the control. A second relay
may be present for zones 4 and 5.
Wrong Zones Operating
Change the damper wires on the
terminal block. Refer to the labels on the
thermostat wires and colour code at the
damper connections.
Pump does not run
The pump is activated by a 12vdc DPDT
relay powered by the control. One side
runs the pump (120vac) and the other
side provides a dry contact (TT) for a
boiler. If the PUMP LED is illuminated
but the pump does not run, the issue is
the pump.
• Seized due to lime build-up; clean
or replace
• Air bound (re-purge)
• Valves closed in error
Second Stage Air Conditioning
Second stage air conditioning is
activated by a 12vdc DPDT relay
powered by the control. Only one set of
contacts is used to provide 24vac to the
air conditioner second stage. First stage
Page 17 ZC-KI6_VSS1709
is driven from the control through the 8gang relay.
Insufficient or no heat
• Plugged air filter or coil. Refer to
Maintenance section for filter care
and coil cleaning.
• Air in heating loop; purge system.
• Inlet and outlet connections to air
handler backwards; reverse
connections.
• Water heater supply tube (dip
tube) is restricted or damaged;
check and/or replace.
• Supply water temperature set too
low or not calibrated properly;
check water temperature. In the
case of water heater; If the
temperature has been set low
because of homeowner
preference, it may be necessary
to install an anti-scald valve to
control the faucet temperature and
raise the operating temperature of
the water heater.
• Restrictions in heating loop;
remove restrictions, check valve
stuck, isolation valves too
restrictive, left partially closed after
purging or closed valve.
Cold water at hot faucet
When heat source is a water heater, the
most probable cause is reverse flow
through the heating loop from a stuck
check valve or a faulty single-lever faucet
somewhere in the home; repair or
replace valve.
Fan runs for cooling but not heating
Room thermostat may be connected
improperly. Refer to Electrical section or
wiring schematic on air handler for
proper installation.
Heating during Standby Mode
Probable cause is thermal siphoning.
See check valve description for details;
repair or replace check valve. Check
elevation of air handler above water
heater to see if motorized valve required
for positive shut-off.
Page 18 ZC-KI6_VSS1709
ZONE COMFORT ISTAT6 Air Handler Parts & Accessory List
Part No. Description
L,
L
0L,
C24L,
L
L,
L
L,
L,
L,
L
L,
100L
UC20203
UC20203ASS Coil assembly c/w pump-20x20
UCA100
GUPS15-58RU
GUPS26-99BFC
XED008
XED010
XELH620
XELK710
XELK711
XELK715
XELK721
XELK725
XELK740
XELR012DC5L
XELR024DPDT5L Relay 24VAC DPDT, DIN rail + LED S S S S S
XELT002
Hot Water Coil – 20”x20” S S S S
S S S S
Hot Water Coil – Dual 20x20 S
Pump-Grundfos S S S S
Pump-Grundfos c/w check S
8in. motorized damper S S
10in. motorized damper S S S
Wire Harness - power S S S S S
EVO ECM motor speed control S S S S S
Motor speed cable S S S S S
8 Gang Relay Board S S S S S
10k Thermister S S S S S
Remote monitoring gateway O O O O O
iStat6 Programmable control S S S S S
Relay 12vdc DPDT, DIN rail + LED S S S S S
Transformer 24VAC, 40 VA S S S S S
XELD002
XECM03E
XECM04E
XECM06E
XBLF108
XBLF128T
CPVA06
S=Standard, A=Alternate, O=Option
Contact Vortex for blower/control assemblies or cabinet parts.
Door interlock switch S S S S S
EC Blower motor -- -1/3 HP S
EC Blower motor -- -1/2 HP A S S
EC Blower motor -- -3/4 HP S S
Blower – 10x8 DD S S S
Blower – 12x8T DD S S
Valve Assembly – ¾” full port sweat
ball valves plus drain
Page 19 ZC-KI6_VSS1709
O O O O
Product Warranty
This product is warranted by Vortex Source Systems to be free from defects in materials and
workmanship that affect product performance under normal use and maintenance within the
applicable periods specified below. Replacements furnished will carry only the un-expired
portion of the original warranty.
Two-Year Parts
Vortex Source Systems will provide replacement parts for ANY part that fail within two years of
purchase, subject to the terms below.
Five-Year Parts
Vortex Source systems will provide replacement parts for any heating coils, cooling coils,
cabinetry and piping that fail within five years of purchase, subject to the terms below.
Terms
Reasonable proof of original purchase date must be provided in order to establish the
effective date of the warranty, failing which, the effective date will be based on the date of
manufacture plus thirty days.
The warranty does not cover failure or damages caused by:
improper installation or operation
accident, abuse or alteration
operation of device at temperatures or pressures outside of the rated capacities
lime or scale deposits
corrosive operating environment
equipment moved from original installation location
Replacements furnished under this warranty will be F.O.B. Vortex Source Systems product
distribution points in the United States and Canada. They will be invoiced at regular prices.
The account will be credited the full amount when the defective part is received by Vortex,
examined and approved as a valid warranty.
Warranty applies to the original purchaser, but may be transferred to another owner
provided the equipment is not moved from the original installation site.
This warranty does not apply to labour, freight or any other cost associated with the service
repair or operation of the product.
Vortex shall not be liable for any direct, special, incidental or consequential damages
caused by the use, misuse, or inability to use this product.
Vortex is under no legal obligations to rectify, including but not limited to, lost profits,
downtime, good will, damages to, or replacement of equipment and property
Purchaser assumes all risk and liability of loss, damage or injury to purchaser and
purchaser’s property and to others and their property arising out of the use, misuse or
inability to use this product.
Page 20 ZC-KI6_VSS1709
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