Commercial HVAC problems do not always appear during the hottest or coldest days of the year. Some issues become noticeable during seasonal changeovers, when buildings move from steady cooling demand to a mix of cooling and heating throughout the day.

Those changing operating conditions can expose problems that were difficult to detect during the summer.

Heating Components May Have Been Idle for Months

Many heating components are used little, if at all, for a large part of the year in Arlington and Fort Worth commercial buildings. The first meaningful call for heat may reveal a problem that has been developing unnoticed for months.

Depending on the equipment, seasonal startup problems may involve ignition components, burners, safety devices, valves, pumps or other parts of the heating system.

Facility managers may not become aware of the problem until outdoor temperatures finally create enough heating demand for the system to operate for an extended period.

Heat Pumps Have to Change How They Operate

Heat pumps create another potential changeover issue because the same refrigeration system is used for both heating and cooling.

After operating in cooling mode throughout the summer, the system must reverse the refrigeration cycle when heating is required. Problems involving the reversing valve, defrost system or other heating-related components may not affect cooling performance at all.

As a result, a heat pump that performed reliably throughout the summer can still develop problems as soon as the building begins calling for heat.

Seasonal Changeovers Can Expose Outdated Operating Assumptions

HVAC schedules and setpoints are often carried forward from the previous heating or cooling season. If the building has changed since then, those settings may no longer match current conditions.

For example, a tenant improvement completed during summer may change occupancy, room layouts or internal heat loads. When fall arrives, the previous year’s heating schedule may be restored even though the space now behaves differently.

Economizer Problems May Become More Noticeable

Under appropriate conditions, an economizer can reduce the need for mechanical cooling by bringing cooler outside air into the building. However, problems involving dampers, actuators or sensors may become apparent when economizer operation increases during fall.

A damper that does not open properly can prevent the system from taking advantage of favorable outdoor conditions. A damper that remains open when it should not can introduce excessive outdoor air and affect temperature control.

Because economizers may operate differently depending on outdoor conditions, these problems can appear intermittently rather than producing a constant, easily identifiable failure.

Mixed Heating and Cooling Demands Can Reveal Building-Level Problems

Fall can also expose differences between areas of a commercial building that were less apparent during peak summer.

Perimeter offices may require heating on a cool morning while conference rooms, server areas or densely occupied interior spaces continue generating enough heat to require cooling. Solar exposure can cause those demands to change again later in the day.

These conditions can reveal airflow, zoning or system coordination problems that are difficult to recognize when virtually every area of the building is calling for cooling.

The HVAC equipment itself may still be operational. The problem may instead involve how conditioned air is distributed or how different areas of the building respond as loads change throughout the day.

Seasonal HVAC Problems Can Be Difficult to Diagnose in Tarrant County Buildings

One of the challenges with seasonal changeover problems is that they may not happen continuously.

A facility manager might receive complaints about a cold area at 8 a.m. only for the space to be comfortable by the time a technician arrives at noon.

Another problem may appear only when the outdoor temperature falls within a particular range or when the system switches operating modes.

Keeping track of when the problem occurs, which areas are affected, whether the system is heating or cooling and what the outdoor conditions are can provide useful information during troubleshooting.

If your facility develops intermittent heating, cooling or comfort problems as temperatures begin changing, call Tom’s Commercial at (817) 857-7400.