How can I find the instruction manual for a tekmar control?

Each tekmar product has a three-digit product number. Most controls have the three-digit product number on the front; thermostats will have the three-digit product number inside the wiring area. Once you find the product number you can locate the installation and operation manual or the user manual on the tekmar website.

I have a tekmar thermostat that shows OPN or OPEN. What does this mean?

OPN or OPEN means that there is an open electrical circuit on an auxiliary temperature sensor input. In the wiring area, check to see if an auxiliary sensor has been connected to the thermostat. If there are no wires connected to the auxiliary sensor terminals, the SENSOR setting in the ADJUST MENU can be set to OFF to correct the problem. If there is a sensor connected, check the wiring for loose connections or broken wires. In some cases the auxiliary temperature sensor may have failed and requires replacement. For specific information, find out the three digit type number of the thermostats (shown in wiring area), and then refer to the product Installation and Operation Manual that is available on our website. Once the issue has been corrected, it is recommended to change the thermostat to the User access level.

Why won’t my boiler(s) fire? I wired the control with power and connected my boiler to it but it is not turning on the boiler(s). The boiler does fire when I press the test button.

Classic series tekmar controls require a call for heat, or demand, to be applied to the control. Check the display to see if a boiler demand is present, you may not have provided a demand to the control. Use the building thermostat, or end switches from zone valves or zone pump relays to apply either 24 V (ac) power to the demand terminals on the control.

I have a Boiler staging control and a couple of mixing controls (classic series). It doesn’t seem as if the mixing controls are providing enough heat and the building is under heating.

Both the Boiler staging controls and the Mixing controls have a ‘Boiler Minimum’ setting to protect the boiler(s). The boiler and mixing controls are reading the boiler temperature at different locations, supply vs. return. Therefore, you must set the ‘Boiler Minimum’ setting on the mixing controls at least 20°F cooler than the ‘Boiler Minimum’ setting on the boiler staging control. Otherwise the mixing controls back off too soon while the boiler control thinks everything is okay.

I have two controls on my system, can I connect them both to one outdoor sensor?

No, for classic series controls each control requires its own outdoor sensor. Example: Two 356 mixing controls, each require their own outdoor sensor 070.

However, professional and designer series communicating controls use a network to share information such as the outdoor temperature. Once a single outdoor sensor 070 is connected to a control or thermostat, the outdoor temperature is available on all products within the system.

My building is under heating, especially when it’s cold outside.

On the display the boiler control will show the outdoor temperature reading in the View menu. In some cases, the outdoor temperature is reading much warmer than the actual ambient outdoor air temperature. This results in the heating system using cooler water temperatures to heat the building.

The location and installation of the outdoor air sensor on the outside of the building is very important. The outdoor sensor should be installed on a north-facing wall and away from any heat sources such as direct sunlight, vents, doors, and windows. Warm air from the building can travel from inside the building along the hole in the wall where the sensor wire is pulled. Ensure this hole is sealed using silicone or spray foam.

I have a snow melt control and it is showing a RED ERR (664, 665, 667), Err 10 (662) or % Output Err (661).

These errors indicate there is a failure in the 090 sensor and that the sensor requires replacement.

I have a mixing control and it shows a mixing demand but it will not open the mixing valve or the variable speed injection pump.

Mixing controls are designed to provide boiler return protection. On the control display, check the boiler temperature measurement in the View menu. Then enter the Adjust menu and check the BOILER MIN setting. If the measured boiler temperature is below the boiler minimum setting, the mixing control is designed to close the mixing valve or reduce the speed of the variable speed injection pump.