Installer Manual

Commissioning

As with any thermostat, commissioning ensures that the thermostat and the equipment connected to it are operating correctly and as expected. Although the SMT-770 is a multifunctional thermostat, commissioning is quite a simple process. Follow the steps

detailed below and use the troubleshooting guide on page 44 if you encounter a

problem.

When the thermostat is fitted to the base plate and when 24VAC power is first applied, the LCD should briefly show all available segments (a LCD function test) then display the software version number before showing the time and operating mode etc.

The SMT-770 is fitted with a number of safety and energy saving time delays. If desired, these can be disabled for commissioning purposes by entering the installer mode and setting the CD=00 value to read CD=01. After exiting the installer menu you will note a “Spanner” icon flashing on the LCD to remind you that commissioning mode is Active. After commissioning has been completed it is important to disable commissioning mode by entering the installer menu once again and setting the CD=01 value back to CD=00.

Note- when in commissioning mode ALL time delays are either OFF or reduced to a extremely low value, it is therefore normal to potentially call for 3 rd

stage heating almost instantly 0.5deg below the heating set point.

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If you choose not to use commissioning mode you may see various words and Icons flashing in the LCD whenever a time period is in use. For example, the word “HEAT” may flash to indicate heating is required but being held off by the 4 minute anti-cycle timer. Or the word “HEATING” may be flashing to indicate set point has been achieved however heating is being held ON by the minimum run timer.

The golden rule with the SMT-770 is anything that flashes is a timer

overriding what would normally be expected to occur; either a function is being held on or off momentarily.

Please be patient.

Test fan operation.

With the thermostat OFF (tap the mode button to show OFF in the LCD). Simply tap the fan button to cycle through the available fan speeds. As the LCD changes to show the fan speed or fan mode you should here faint “clicks” as the SMT-770 internal relays change, the equipment fan speed should change accordingly.

Test heating and cooling (if both fitted).

Turn the SMT-770 to Auto season change mode by tapping the mode button until the words “Heat” and “Cool” are shown on the LCD.

Using the temp  or Temp  button set the desired temperature a few degrees below the ambient temperature. After a few moments you will hear a click and the word

“Heat” will change to “Heating”. Verify that the heating system is on and operating

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correctly. If stage 2 heat is being called the full stop “.” on the end of the word “MODE” will be seen to indicate 2 nd

stage heat. Stage 3 of heat is indicated by the full stop flashing.

Using the temp + or Temp – button set the desired temperature a few degrees above the ambient temperature. After a few moments you will hear a click and the word

“Cool” will change to “Cooling”. Verify that the cooling system is on and operating correctly. When stage 2 cool is being called, the full stop “.” on the end of word

“MODE” mode will be seen to indicate 2 nd

stage cool.

Tap the mode button turn the SMT-770 OFF. After any necessary timers have expired all heating, cooling and fan functions should stop. Verify that the system has shut down.

Note, in HP mode (SW2=ON) it is normal for the reversing valve to remain energised after the compressor has stopped. This is done to prevent “decompression HISS” and to limit the wear on the reversing valve. 30 minutes after the last reversing valve use it will de-energise to conserve power.

If commissioning mode has been used it is important that the function be turned OFF before handover to the user.

Using the User Manual as a guide set the real time clock and the preferred user programme (if applicable). Explain equipment & thermostat operation to the user.

Commissioning is complete.

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