Sachs Consulting

HVAC and Building Controls Commissioning Experts



Terminal Units Training & Troubleshooting


Identify what type of unit it is:



            Series box

            Parallel box

            Is it electric heat, hot water heat, steam heat.


Identify what type of controls:






Identify what the problem is:


                        Is the fan coming on.

                        Is the fan motor bad.

                        Is the 1st and or 2nd stage of heat energizing.

                        Are the heat strips burned out.

                        Do we have control power.

                        Is the air flow safety switch made.

                        Is the high temp overload cut out open.

                        Is ultra high temp manual reset open.

                        Is the minimum primary air flow requirement met.

                        Is the control board bad.


                        Is there primary air available.

                        Is the air valve opening.

                        Are the pressure transducer lines pinched or disconnected.

                        Is the pressure transducer functioning properly.

Do we have low voltage.

Is the actuator working ok.

Is the control board bad.

How to calibrate actual air flow in cfm.