HVAC Procedure and Performance Guide

Calibrate humidistat

Training for this procedure can be found in these courses:

                         131 – Oil Heat l  and  161 – Boilers l


Humidistat must be calibrated according to manufacturer’s specifications. Calibrated humidistat must respond to humidity level of space in which sensing element is located and humidistat must control humidifier to maintain space relative humidity within specified limits.  Applicable safety procedures must be followed.


  1. Review manufacturer’s specifications.
  2. Collect tools, equipment and materials.
  3. Put on safety and protective equipment and apparel.
  4. Determine humidity of space and compare to humidistat setting.
  5. Reset humidistat and determine that humidistat responds; note when humidistat is satisfied.
  6. Check space humidity again and adjust humidistat according to manufacturer’s specifications to correspond to test readings.
  7. Leave equipment in required operating status.
  8. Remove safety and protective equipment and apparel.
  9. Gather tools, equipment and leftover materials, and leave work site clean.