KLH Engineers

Reduce potential temperature / equipment issues for hydronic systems

With upcoming cold weather, when temperatures hover below zero, we'd like to remind you of some proactive steps that you can take with your building and HVAC systems to help reduce potential indoor temperature and equipment issues.

  • · Have your mixed air low limit sensor tested. This is one of the first lines of defense in preventing coil freezing.
  • Have your freezestats tested to confirm proper working order.
  • Cycle or exercise your outside air dampers and exhaust air dampers to ensure proper operation. Repair or replace actuators or dampers as needed.
  • Cycle or exercise your hot water control valve to ensure proper operation.
  • Keep a watchful eye on plenum space temperatures. If plenum space temperatures start falling below 60F, remove a few ceiling tile to allow warmer air to circulate through the plenum space.
  • Check heat trace systems for water piping for proper operation. This includes storm, sanitary, sprinklers, domestic water and other piping systems that may be exposed to outdoor temperatures.
  • Check glycol percentages.
  • Consider temporarily disabling night setback features on the HVAC systems. Heating systems will work harder and longer during extreme outside temperatures especially during morning warm-up sequences.
  • Consider temporarily leaving a portion of the interior lighting systems on during night setback. The lighting system can be used as an additional heating source. This is less effective if high efficient luminaires are installed.
  • Make sure all doors and windows are fully closed and their weather seals are in good working condition.
  • Check your stairwells, storage rooms, vestibules, etc… that have unit heaters and wall heaters. Make sure these supplemental forms of heating are operating properly.
  • Verify if your outdoor air sensors are working properly. If your outdoor temperature sensor is indicating 20F, verify the reading with a thermometer.
  • Refer to you O&M manuals for additional maintenance recommendations.

To protect your building and system components from the adverse effects of subzero outside air temperatures, you may need to temporarily reduce outside airflows.  Please note that this should be done with caution as it may negatively affect building pressures resulting in overwhelming HVAC systems near building entrances. 

Taking a proactive approach to checking these items may save you from costly repairs or shutdowns in the future.


Kris Schnitgen, PE, LEED AP

Kris Schnitgen, PE, LEED AP | Principal | Fort Thomas, Kentucky

A member of the firm since 2004, Kris has designed HVAC, plumbing and fire protection systems for the healthcare, education, civic, retail, and commercial market segments. He now manages the entire KLH mechanical department and has been the lead mechanical engineer and project manager for countless projects.