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Tekmar Universal Reset Module 422 - User Manual

Tekmar Universal Reset Module 422
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D 422
08/07
- Data Brochure
Universal Reset Module 422
1 of 32 © 2007 D 422 - 08/07
tN4 Compatible
Two Outdoor Reset Temperatures
Single On-Off or Modulating Boiler
Powered Pump Outputs
DHW Operation
Variable Speed Injection Pump
Floating Action Valve
Includes Sensors
Features:
Information
Brochure
Choose controls
to match
application
1
Application
Brochure
Design your
mechanical
applications
2
Wiring
Brochure
Wiring and
installation of
specific control
4
Job
Record
Record settings &
wiring details for
future reference
6
Data
Brochure
Control settings
and sequence of
operation
5
Rough-in
Wiring
Rough-in
wiring
instructions
3
The Universal Reset Module 422 provides outdoor reset to a hydronic heating system in order to maximize comfort and
efficiency. The 422 can operate a single on / off boiler or a single modulating boiler. The 422 can override the outdoor reset
water temperature to provide Domestic Hot Water or Setpoint operations. The 422 can operate two outdoor reset water
temperatures, either one boiler water temperature and a single mix water temperature, or two mix water temperatures. To
operate two mixing devices, a Mixing Expansion Module must be connected to the 422. The single mix output can operate
a floating action mixing valve or a variable speed injection pump.
Introduction
51
52 53 54 55 56 57 58 59 60 61 62 63 64 65
Boiler DHW Setpoint C C2 tN4 C Com Boil Mix Com Out+Opn Cls
Demand Demand 24 V (ac) Boil/Mix2 R R Mod (dc)
R
66 67 68 69 70
Primary Mix Sys P1
10 A
max.
75 76 77 78
NN
DHW Variable Speed
71 72 73 74
Pump Pump
N
Pump NPump
tN4
H7008B
tN4 Boiler / Mix 2
Boil Sens Sup / Ret
Boiler On-Off / Mod
Off / tekmar Stager
Off / Flushing
Powered OutputOutput 1 VA
Floating Output:
24 V (ac) 8 VA
Made in Canada
Meets Class B: Canadian
ICES & FCC Part 15
Test
Var. Pump Fuse
T2.5 A 250 V
Universal Reset Module 422
Item
Menu
tektra 991-03
Var. Pump: 115 V (ac) 2.5 A
Demands: 20 - 260 V (ac)
Relay Rating: 115 V (ac) 5 A
/
Do not apply power
2.5 A

Other manuals for Tekmar Universal Reset Module 422

Questions and Answers

  • W
    William SanchezJul 25, 2025
    What to do if my Tekmar Control Unit display is not on?
    • J
      james97Jul 25, 2025
      If the display is not on, first verify that there is voltage reaching the control by checking the breaker panel or disconnect and testing the voltage with a voltmeter. Next, make sure the plugs are securely connected between the 422 and the Zone Manager pins. Finally, inspect the fuse on the Zone Manager and check the total VA draw on all thermostats and zone valves connected to the Zone Manager, ensuring it does not exceed 40 VA. If the fuse is blown, replace it.
  • C
    Connor SanchezAug 2, 2025
    Why Tekmar Control Unit boiler does not fire when there is a DHW or Setpoint Demand?
    • C
      Craig SmithAug 2, 2025
      The boiler might not fire due to several reasons. There may be no voltage present on the demand terminals, so test the voltage across the demand terminals using a voltmeter. The control could be in Unoccupied mode and DHW Unoccupied or Setpoint Unoccupied is set to OFF, so check which schedule the 422 is operating on. Also, the boiler contact might not be connected to the boiler thermostat connection; in this case, trace the wires from the boiler contact to the boiler thermostat connection and use the Test sequence to check the boiler contact.
  • A
    Andrew RodriguezAug 9, 2025
    What to do if Tekmar Universal Reset Module 422 Control Unit variable speed injection pump does not operate?
    • A
      Alicia GravesAug 9, 2025
      If the variable speed injection pump isn't working, first check that the Mix 1 Mode setting is set to VAr, because there may be no current present on the variable speed injection pump. Also, the variable speed injection pump will not operate until the boiler supply temperature exceeds the boiler minimum setting due to Boiler Return Protection. Ensure that a wet rotor pump has been installed. If a non-wet rotor pump has been installed, read E 021 and check pump type. Finally, check if the fuse is blown; if so, determine if the pump is jammed or seized and replace the fuse.
  • R
    Roy MartinAug 16, 2025
    How to fix a Tekmar Control Unit mixing valve that will not open?
    • M
      meganallenAug 17, 2025
      If the mixing valve won't open, it could be due to several reasons. Check that the Mix 1 Mode setting is set to FLt, because there may be no voltage present on the actuator motor. The mixing valve will also not open until the boiler supply temperature exceeds the boiler minimum setting due to Boiler Return Protection. Another possible cause is the actuator rotating in the wrong direction to open the valve; if this is the case, reverse the open and close wires on the actuator.

Summary

Display and DIP Switches

Dip Switch Settings

Set the DIP switch settings prior to making adjustments to the control through the user interface.

Adjust Menu

Adjust Menu Settings (1 of 5)

Details the programmable settings for operating the mechanical equipment.

Control Testing

Test Sequence

Describes the built-in test routine for checking control functions and individual outputs.

Sequence of Operation

Outdoor Reset Operation

Describes how outdoor temperature affects heating system water temperature via a characterized heating curve.

Boiler Outdoor Reset

Mix 1 and Mix 2 Outdoor Reset

Boiler Temperature Control

Boiler Minimum

Sets the lowest allowed boiler target temperature to protect the boiler.

On-Off Boiler Operation

Boiler Differential

Explains how differential settings prevent short cycling in on-off boilers.

Modulating Boiler Operation

Modulation Settings

tekmar Stager Operation

Boiler Enable

Zone Load Shedding

Mixing Operation

Mix 1 Mode

Selects the type of mixing device for Mix 1, either variable speed injection or floating action.

Domestic Hot Water (DHW) Operation

DHW Mode and Priority Operation

DHW Mode 2: Parallel, Priority

Describes DHW mode with priority, shutting off zones if boiler cannot maintain target temp.

DHW Mode 4: Primary;Secondary, Priority

Describes DHW mode with priority, shutting off zones if boiler cannot maintain target temp.

DHW Priority Override

Setpoint Temperature Operation

Setpoint Modes

Pump Operation

Error Messages

Locating Error Messages

Provides steps to view error messages on the control's display.

Boiler Bus Error

Indicates communication loss on the boiler bus, requiring wire checks.

Bus 1 Error

Indicates communication loss on the Mix 1 bus, requiring wire checks.

Bus 2 Error

Indicates communication loss on the Mix 2 bus, requiring wire checks.

Mix 1 Sensor Short Circuit

Indicates a short circuit in the Mix 1 supply sensor, resulting in fixed output operation.

Mix 1 Sensor Open Circuit

Indicates an open circuit in the Mix 1 supply sensor, resulting in fixed output operation.

Mix 2 Sensor Short Circuit

Indicates a short circuit in the Mix 2 supply sensor, resulting in fixed output operation.

Mix 2 Sensor Open Circuit

Indicates an open circuit in the Mix 2 supply sensor, resulting in fixed output operation.

Boiler Sensor Short Circuit

Indicates a short circuit in the boiler sensor, disabling control and providing boiler enable.

Boiler Sensor Open Circuit

Indicates an open circuit in the boiler sensor, disabling control and providing boiler enable.

Boiler Bus and Return Sensor Conflict

Indicates a DIP switch conflict between Boiler and tN4 bus settings.

tekmar Stager Setting Conflict

Indicates a DIP switch conflict between tekmar Stager and Boiler Sensor settings.

Troubleshooting

Tekmar Universal Reset Module 422 Specifications

General IconGeneral
Model422
CategoryControl Unit
Input Voltage24 VAC
Operating Voltage24 VAC
Output Voltage24 VAC
MountingSurface mount
Temperature Range0 to 50°C
Operating Temperature0 to 50 °C
ApplicationUniversal Reset Module

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