Before Replacing Commercial HVAC Equipment, Check the Controls
When a commercial building has uneven temperatures, recurring complaints or rising utility bills, equipment replacement can quickly enter the conversation. Before approving a major project, ask your mechanical contractor to review how the existing system operates.
Schedules, sensor readings, setpoints and equipment sequencing all belong in that review. For Ontario property managers responsible for commercial, multi-residential and institutional buildings, the aim is a clearer decision: what should be adjusted, what needs repair and what should be replaced?
Five questions for a controls review
1. Do operating schedules match the building?
Review start-up times, evening operation, weekends and holiday settings against actual occupancy. Have tenant hours changed? Were temporary overrides left in place?
Different areas may need different schedules. An office, an apartment building's common areas and an institutional space should each be assessed against their actual use. Any proposed adjustment should account for comfort, ventilation, freeze protection and other operational requirements.
2. Are heating and cooling operating as intended?
Ask whether setpoints and control sequences support the building's needs through changing outdoor conditions. Where heating and cooling operate together, the contractor should establish whether that is required by the system's design or points to a control issue.
The review should identify conflicting settings or overrides and explain the proposed correction before changes are made.
3. Can the sensor readings be trusted?
Ask the provider to verify relevant temperature, pressure and airflow readings against actual conditions. Which sensors need checking or calibration? Are the readings available to the control system reliable enough to support the decisions it makes?
Record the findings so future troubleshooting starts with a known baseline.
4. Are pumps and fans responding to demand?
Where variable-speed equipment is installed, ask whether its controls respond appropriately as demand changes. The review should consider the equipment's design and required flow, pressure and ventilation conditions.
A recommendation should explain what will change, why the change is appropriate and how satisfactory operation will be confirmed.
5. Is equipment starting and staging correctly?
Ask the contractor to review when boilers, chillers, rooftop units and supporting equipment start, stop or add capacity. Compare actual operation with the intended sequence.
Where trend data is available, use it to investigate recurring complaints and unusual operation. Ask for any remaining alarms, overrides or control limitations to be documented.
Turn the findings into a decision
A useful review should leave you with a written explanation of the problems found, the recommended work and the basis for each recommendation.
Ask the provider to distinguish between adjustments, component repairs and equipment replacement. For each proposed action, request an explanation of the expected outcome, the cost and any disruption to building operations.
Record changes to settings and schedules, then agree on a follow-up period to check the result. When comparing energy use, account for changes in weather, occupancy and operating hours.
This approach is consistent with ENERGY STAR's operation and maintenance guidance, which recommends reviewing schedules, setpoints and occupant needs and keeping control documentation current.
Plan the next step with RackAir
RackAir's controls and energy management services support existing building systems and help identify operating issues. If you are weighing an equipment replacement or dealing with recurring comfort complaints, contact RackAir to discuss a controls review and the information needed to make the next decision.