Tekmar 521 User manual

Programmable Thermostat 521
Installation & Operation Manual
521
_
D
12/20
Zoning Replaces: 01/14
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A Watts Water Technologies Company
The Programmable Thermostat 521 is
designed for three different modes of
operation: single stage heating, two stages
of heating with a fan, or one stage of
heating and one stage of cooling with
a fan. Two auxiliary sensors may be
added to measure the floor, outdoor or
room temperature. A Slab Sensor 079 is
included to measure floor temperature to
protect the floor from overheating and
enhance comfort. The programmable
schedule supports either a 7 day or 24
hour schedule with 2 or 4 events per day.
A permanent temperature hold button
overrides the programmable schedule.
An optional Adaptor Plate 012 is available
to allow the thermostat to mount onto a
single gang electrical box.
Introduction
Energy Saving Features
• 7 Day Programmable Schedule
Additional Features
• Optimum Start
• Permanent Temperature Hold
• Radiant Floor Heating
• Two Stage Heating
• Cooling
• Fan
• Backlight
• Outdoor and Floor Temperature
Display
• Time Clock
• Four Hour Battery-free Clock
Backup

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Congratulations on the purchase of your new tekmar® thermostat.
This manual will step through the complete installation, programming and sequence
of operation for this control. At the back, there are tips for control and system
troubleshooting.
Getting Started
Table of Contents
Getting Started ...............................2
Important Safety Information ...............3
Installation ...........................................4
Preparation .....................................4
Removing The Thermostat Base ....4
Mounting The Thermostat ...............5
Slab Sensor 079 Installation ...........6
Slab Sensor 079 Wiring .................7
Slab Sensor 079 Testing .................8
Temperature vs. Resistance Table ... 8
Thermostat Wiring .....................9 -11
Testing the Thermostat Wiring ......12
Switch Settings ..................................13
User Interface ....................................14
Home Screen ................................14
Symbols Description .....................14
Programmable Settings .....................15
Fan Menu ......................................15
Set Temp Menu .............................16
Time Menu ....................................17
Schedule Menu ........................18-19
Setup Menu ............................. 20-21
Sequence of Operation ......................22
Mode Button Operation ................22
Heating Operation .........................22
Cooling Operation .........................23
Fan Operation ...............................23
Time Clock ....................................24
Programmable Schedule ..............24
Optimum Start ...............................25
Temperature Adjustment...............25
Access Levels ...............................25
Troubleshooting .................................26
Error Messages ............................26
Frequently Asked Questions .........27
Technical Data ..............................27
Limited Warranty and Product
Return Procedure .........................28

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A Watts Water Technologies Company
To avoid serious personal injury and damage to the equipment:
Important Safety Information
It is your responsibility to ensure that this control is safely installed
according to all applicable codes and standards. tekmar is not responsible
for damages resulting from improper installation and/or maintenance.
• Read Manual and all product labels BEFORE using the equipment.
Do not use unless you know the safe and proper operation of this
equipment.
• Keep this Manual available for easy access by all users.
• Replacement Manuals are available at tekmarControls.com
• Disconnect all power before opening the control.
• It is the installers responsibility to ensure that this control is safely installed according
to all applicable codes and standards.
• Improper installation and operation of this control could result in damage to the
equipment and possibly even personal injury or death.
• This electronic control is not intended for use as a primary limit control. Other
controls that are intended and certified as safety limits must be placed into the
control circuit.
• Do not attempt to service the control. There are no user serviceable parts inside
the control. Attempting to do so voids warranty.

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Preparation
Installation
Choose the placement of the thermostats early in the construction process to enable
proper wiring during rough-in.
Consider the following:
• Interior Wall.
• Keep dry. Avoid potential leakage onto the control.
• Relative Humidity less than 90%. Non-condensing environment.
• No exposure to extreme temperatures beyond 32-122°F (0-50°C).
• No draft, direct sun, or other cause for inaccurate temperature readings.
• Away from equipment, appliances, or other sources of electrical interference.
• Easy access for wiring, viewing, and adjusting the display screen.
• Approximately 5 feet (1.5 m) off the finished floor.
• The maximum length of wire is 500 feet (150 m).
• Strip wire to 3/8" (10 mm) for all terminal connections.
• Use standard 5 conductor, 18 AWG wire.
Installation Location ------------------------------------------------ ------------------------------------------------
• tekmar or jeweller screwdriver
• Phillips head screwdriver
• Wire Stripper
Tools Required ----------------------------------------------------- -----------------------------------------------------
Materials Required ------------------------------------------------- -------------------------------------------------
• 18 AWG LVT Solid Wire
(Low Voltage Connections)
Removing The Thermostat Base
To remove the thermostat base:
• Locate the tab on the bottom of the thermostat.
• Push the tab with either your thumb or with a
screwdriver.
• Lift the thermostat front away from the
thermostat’s base.

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Mounting The Thermostat
If mounting directly to the wall:
• Drill holes and install the wall anchors.
• Feed the wiring through the large hole in the thermostat base.
• Fasten the thermostat base to the wall using the wood screws to the wall
anchors.
• Terminate wiring to the wiring strip.
• Push the thermostat front onto the thermostat base.
If a single gang box is used:
• Adapter Plate 012 is required (sold separately).
• Feed the wiring through the hole in the adaptor plate and the thermostat base.
• Fasten the adaptor plate to the gang box.
• Fasten the base of the thermostat to the adaptor plate.
• Terminate wiring to the wiring strip.
• Push the thermostat front onto the thermostat base.
Wall
Thermostat
Front
Thermostat
Base
3 1/4"
(83 mm)
Stud
Gang
Box
Thermostat
Front
Thermostat
Base
Adapter Plate 012

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Thick Floor Coverings (greater than 3/8" (10 mm))
If a thick floor covering is to be installed directly to the subfloor, a groove 1/8" (4 mm) wide
by 1/16" (2 mm) deep can be cut into the back of the flooring material to accommodate
the wire for the sensor. Ensure that the sensor is located in such a position that the
attached wire is able to reach to a suitable junction location.
Splices under the floor covering should be avoided
to ensure trouble free operation. A groove 3/16"
(5 mm) wide by 3/16" (5 mm) deep by 1-3/4" (45
mm) long should be cut to accommodate the
sensor. The sensor should be located mid way
between the heating elements to ensure a proper
temperature reading.
If it is not practical to cut a groove in the surface
covering, follow the installation method used for
thin floor coverings.
Slab Sensor 079 Installation
Thin-Set or Thin-Pour Applications
If the floor covering is to be installed over either a thin-set or thin-pour material of sufficient
depth, the 079 slab sensor can be placed directly into either the thin-set material or the
thin-pour material and covered over. Ensure
that the sensor is located in such a position that
the attached wire is able to reach to a suitable
junction location. Splices within the thin-set or
thin-pour should be avoided to ensure trouble
free operation. The sensor should be located
mid way between the heating elements to ensure
a proper temperature reading.
Tiles
Thin-set
Electric
Cables
Thin Floor Coverings (less than 3/8" (10 mm))
If a thin floor covering is to be installed directly to the subfloor, a groove 1/8" (4 mm)
wide by 1/16" (2 mm) deep can be cut into the surface of the subfloor to accommodate
the wire for the sensor. Ensure that the sensor is located in such a position that the
attached wire is able to reach to a suitable junction
location. Splices under the floor covering should
be avoided to ensure trouble free operation.
A groove 3/16" (5 mm) wide by 3/16" (5 mm)
deep by 1-3/4" (45 mm) long should be cut to
accommodate the sensor. The sensor should be
located mid way between the heating elements to
ensure a proper temperature reading.
Hardwood
Subfloor
Hardwood
Subfloor
New Installations --------------------------------------------------- ---------------------------------------------------

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Tile Floor Coverings
If a Slab Sensor 079 is to be installed into an existing tile floor with sufficiently large
grout lines, the sensor and wire can be installed in one of the grout lines between the
tiles. Select a low traffic area of the floor that is mid way between the heating elements
for the sensor location. Ensure that the sensor is located in such a position that the
attached wire is able to reach to a suitable junction location. Splices within the grout
should be avoided to ensure trouble free operation. Remove the appropriate grout line
and place the sensor and wire in the floor. Re-grout the area.
Installing the Sensor to the Bottom of a Subfloor
If the sensor is to be installed to the bottom of a subfloor, cut a piece of 1" (25 mm)
thick rigid insulation into a 6" (150 mm) by 6" (150 mm) square. A groove 3/16" (5 mm)
wide by 3/16" (5 mm) deep by 1-3/4" (45 mm) long should be cut into the insulation to
accommodate the sensor. Place the sensor in the groove and sandwich the sensor
between the insulation and the subfloor. Use a suitable fastening method to affix the
insulation to the subfloor.
Retrofit Installations ------------------------------------------------ ------------------------------------------------
The Slab Sensor 079 is supplied with 10' (3 m) of cable. If a longer length is
required, 24 AWG or larger wire can be spliced onto the two wires from the sensor.
The splices should be properly soldered and protected in an accessible junction
box. Follow the sensor testing instructions given in this brochure and then connect
the wires to the control.
Slab Sensor 079 Wiring
Do not run sensor wires parallel to telephone or power cables. If the sensor
wires are located in an area with strong sources of electromagnetic interference,
shielded cable or twisted pair should be used or the wires can be run in a grounded
metal conduit.

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Slab Sensor 079 Testing
A good quality test meter capable of measuring up to 5,000 kΩ (1 kΩ = 1000Ω) is
required to measure the sensor resistance. In addition to this, the actual temperature
must be measured with either a good quality digital thermometer, or if a thermometer
is not available, a second sensor can be placed alongside the one to be tested and
the readings compared.
First measure the room temperature using the thermometer. Disconnect the S1 or S2
and Com wires from the thermostat. Using an electrical meter, measure the resistance
of the S1 or S2 and Com wires at the thermostat location. Using the temperature
versus resistance table, estimate the temperature measured by the sensor. The sensor
measurement and thermometer readings should be close. If the test meter reads a very
high resistance, there may be a broken wire, a poor wiring connection or a defective
sensor. If the resistance is very low, the wiring may be shorted, there may be moisture
in the sensor or the sensor may be defective. To test for a defective sensor, measure
the resistance directly at the sensor location. Once the test has been completed,
reconnect the S1 or S2 and Com wires to the thermostat.
Do not apply voltage to the temperature sensor terminals at any time as damage to
the sensor may result.
Temperature vs. Resistance Table
Temperature Resistance
°F °C
-50 -46 490,813
-45 -43 405,710
-40 -40 336,606
-35 -37 280,279
-30 -34 234,196
-25 -32 196,358
-20 -29 165,180
-15 -26 139,402
-10 -23 118,018
-5 -21 100,221
0-18 85,362
5-15 72,918
10 -12 62,465
15 -9 53,658
20 -7 46,218
Temperature Resistance
°F °C
25 -4 39,913
30 -1 34,558
35 2 29,996
40 4 26,099
45 7 22,763
50 10 19,900
55 13 17,436
60 16 15,311
65 18 13,474
70 21 11,883
75 24 10,501
80 27 9,299
85 29 8,250
90 32 7,334
95 35 6,532

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Temperature vs. Resistance Table - Continued
Temperature Resistance
°F °C
100 38 5,828
105 41 5,210
110 43 4,665
115 46 4,184
120 49 3,760
125 52 3,383
130 54 3,050
135 57 2,754
140 60 2,490
145 63 2,255
150 66 2,045
155 68 1,857
160 71 1,689
Temperature Resistance
°F °C
165 74 1,538
170 77 1,403
175 79 1,281
180 82 1,172
185 85 1,073
190 88 983
195 91 903
200 93 829
205 96 763
210 99 703
215 102 648
220 104 598
225 107 553
Thermostat Wiring
Zone Valve --------------------------------------------------------- ---------------------------------------------------------
C
N
L
R
CR Y/W2 Rc GGRh W1 S1 S2Com
No Power
TT
Zone
Valve
Boiler
Transformer
Field Jumper Required:
R to Rh

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A Watts Water Technologies Company
Wiring Center 315 or 316 -------------------------------------------- --------------------------------------------
Relay 003 ---------------------------------------------------------- ----------------------------------------------------------
Switching Relay ---------------------------------------------------- ----------------------------------------------------
T T
C
N
L
R
CR Y/W2 Rc GGRh W1 S1 S2Com
No Power
2
1
8
7
3
4
5
6
Thermostat Wiring
Boiler
Relay
003
Pump
Transformer
tN4 CW
R
CR Y/W2 Rc GGRh W1 S1 S2Com
No Power
Wiring Center
CR Y/W2 Rc GGRh W1 S1 S2Com
No Power
RW
24 V
RW
HNXX HNHN NH
Com Switching Relay
Zone 1 Zone 2 Zone 3
Class 2
Transformer
RW
Zone 1 Zone 2 Zone 3
Pump
N L
Field Jumper Required:
R to Rh
Field Jumper Required:
R to Rh