A green light on a control panel does not prove that a building is being monitored properly. A flood sensor may be online but mounted above the first water path. A temperature alarm may activate but send its message to a former employee.
Winter turns these gaps into expensive problems. A small leak can spread overnight, a failed heater can freeze a pipe, and an exterior door left open can expose the building to cold, water and unauthorized entry.
Quick answer: A pre-winter detection-system test should confirm sensor placement, activation, zone labels, alarm thresholds, control-panel receipt, local sounders, remote notifications, monitoring-station response and staff escalation. Test the complete route from the physical condition to the person expected to act.
Detection-System Symptoms and Likely Causes
| Symptom | Likely cause | What should be checked |
| Sensor shows normal during a known problem | Poor placement, failed device, damaged wiring or disabled zone | Physical location, activation test, zone status and event history |
| Alarm reaches the panel but no one receives it | Outdated contacts, communication fault or notification rule | Call list, app/email/SMS route, communicator and monitoring account |
| Repeated low-temperature alarms clear quickly | Threshold too close to normal cycling, airflow or missing delay | Setpoint, hysteresis, delay, sensor position and HVAC operation |
| Flood alarm occurs after water has already spread | Sensor mounted too high or away from the first water path | Floor slope, drains, equipment, probe height and cable placement |
| Motion alarms increase during storms | Moving branches, blowing snow, heaters, reflections or drafts | Detection field, sensitivity, object movement and seasonal conditions |
| Door-open alarm remains active after the door closes | Contact misalignment, door sag, ice or latch problem | Magnet gap, hinges, closer, latch, threshold and contact wiring |
| Alarm identifies the wrong room | Incorrect zone label or changes not updated after renovations | Drawings, panel programming, device labels and test records |
| System works on utility power but fails during an outage | Weak battery or unprotected network/communication equipment | Panel battery, UPS, network switch, communicator and runtime |
| Staff receive an alarm but do not know what to do | No written response procedure or unclear ownership | Escalation list, after-hours roles, access and shutoff instructions |
1. Start With an Accurate Device and Zone Inventory
Testing is difficult when the building team does not know what is installed. Create or update an inventory that identifies:
- Device type
- Exact room or area
- Panel and zone number
- Sensor address, where applicable
- Equipment or risk being monitored
- Normal operating range
- Alarm setpoint and delay
- Local and remote notification path
- Backup-power source
- Last test and service date
- Person or contractor responsible for the response
Use names that make sense during an emergency. “Zone 18” is not enough. A useful label might be “P1 sprinkler room—north wall flood cable” or “Level 7 east electrical room—low temperature.”
Walk the building with the current drawings. Renovations, tenant changes and equipment replacements often leave sensors monitoring the wrong place or panel labels describing rooms that no longer exist.
ACS Systems’ Detection Systems page outlines the different devices that may be used for water, temperature, access and intrusion monitoring.
2. Test the Sensor With a Safe, Controlled Input
The test should reproduce the condition the device is meant to detect without damaging equipment or creating an unsafe situation.
Examples include:
- Using the approved test method for a water probe or sensing cable
- Changing a temperature input with approved test equipment
- Opening the monitored door or window
- Walking through a motion-detection field
- Activating a supervised input or approved test control
- Using manufacturer-approved methods for smoke or heat detection
Do not test a fire detector with an open flame, unapproved aerosol, building steam or another improvised method. Fire alarm devices require inspection and testing under the Ontario Fire Code and applicable standards. Review Ontario Regulation 213/07, the Fire Code.
Confirm More Than the Alarm Light
For each controlled test, record whether:
- The sensor recognized the condition.
- The correct zone appeared at the panel.
- The event carried the right time and location.
- The local sounder or indicator operated where intended.
- The communicator transmitted the event.
- The correct person or monitoring station received it.
- The recipient understood what action to take.
- The zone restored normally after the condition cleared.
A failure at any step leaves a gap, even if the sensor itself worked.
3. Review Flood and Low-Temperature Protection Together
Water and temperature problems are closely connected in Canadian buildings. A failed heater can freeze a pipe. A frozen pipe may not leak until the building warms and the split opens.
High-risk areas can include:
- Mechanical and boiler rooms
- Sprinkler rooms
- Water-entry rooms
- Cooling-tower and rooftop-equipment areas
- Server and communications rooms
- Underground parking
- Sump and sewage-ejector rooms
- Vacant tenant areas
- Exterior-wall plumbing spaces
- Rooms below kitchens, washrooms or laundry equipment
Flood Sensor Placement
A point sensor reacts only when water reaches that exact spot. A sensing cable covers a longer path but still needs to follow the likely route of the leak.
Check:
- Floor slope
- Drain and sump locations
- Pumps, valves and pipe joints
- Water-heater and boiler relief paths
- Fan-coil and condensate drains
- Raised equipment pads
- Barriers that may divert water
- Storage that can keep water away from the sensor
ACS Systems provides water flood sensors for commercial and multi-residential buildings. The related article, How to Protect Mechanical Rooms From Water, Fire, and Equipment Failure, explains why one sensor type rarely covers every mechanical-room risk.
Temperature Thresholds and Delays
A low-temperature threshold should provide enough time to act before pipes or equipment are damaged. A high-temperature threshold should reflect the equipment and room being protected.
Review:
- Normal occupied and unoccupied temperatures
- Seasonal HVAC schedules
- Sensor accuracy
- Distance from heaters, vents and exterior walls
- Alarm delay
- Hysteresis or reset difference
- Critical equipment limits
- Expected response time after hours
A sensor beside a supply-air grille may report the temperature of the air stream rather than the room. A sensor on a cold exterior wall may alarm before the equipment area is at risk. Placement and threshold must be reviewed together.
Hi/low temperature monitoring sensors can be connected to building alerts, but the setpoints should be based on the room, equipment and response plan.
4. Check Door, Window and Motion Detection After Seasonal Changes
Door contacts and motion detectors can behave differently after construction, tenant fit-outs or seasonal changes.
Door and Window Contacts
A magnetic contact has a permitted alignment and gap. If the door sags, the frame moves or ice prevents full closure, the contact may remain open even when the door looks closed.
Inspect:
- Magnet and contact alignment
- Loose surface-mounted parts
- Damaged armoured cable
- Door sag and hinge wear
- Closer and latch operation
- Weather seals and threshold ice
- Zone delay and alarm schedule
- Repeated events in the same location
The door and window contact monitoring page explains how openings can be supervised beyond normal credential use.
Motion Detectors
Changes inside the detection field can create false alarms or blind areas. Look for:
- New shelving or partitions
- Hanging signs and decorations
- Space heaters
- Supply-air movement
- Plants or loose plastic
- Reflections from polished surfaces
- Pests
- Snow or branches visible through glass
Do not simply reduce sensitivity until alarms stop. A setting that ignores moving snow may also miss a person at the edge of the protected area. Walk-test the complete area after any adjustment.
ACS Systems installs commercial motion detectors and intrusion sensors that can be coordinated with alarm and monitoring systems.
5. Follow the Alarm Through Every Communication Path
An alarm that remains inside an empty building is not an effective after-hours response system.
Depending on the installation, a signal may travel through:
- Local control panel
- On-site sounder or strobe
- Security desk
- Building-management system
- Mobile app
- Email or SMS service
- Internet communicator
- Cellular communicator
- Central monitoring station
- Property-management escalation list
During the test, confirm:
- The correct event type is transmitted
- The correct building and zone are identified
- Primary and backup communication paths work
- The monitoring account is active
- Contact names and numbers are current
- Call order reflects current responsibilities
- After-hours recipients can enter the building
- Staff know who can isolate water, reset equipment or call a contractor
Avoid sending every minor warning to every manager. Too many low-value alerts can cause alarm fatigue. Classify events by urgency and direct them to someone who can act.
6. Test Backup Power and Recovery
A winter storm can remove utility power, internet service and heating at the same time. Backup planning needs to include the full chain, not only the alarm panel.
Check whether backup power supports:
- Control panel
- Sensors that require external power
- Network switch
- Router and firewall
- Cellular or internet communicator
- Local annunciator
- Security workstation
- Monitoring gateway
- Building-management interface
A battery may show normal voltage at rest and still lose capacity quickly under load. Record battery age, test results and replacement date. Where a UPS is used, review load and expected runtime rather than relying on the front-panel percentage alone.
After a controlled outage or backup-power test, confirm that:
- All zones return online
- The system time remains correct
- Communication restores automatically
- No zone is left bypassed
- Alarm queues clear correctly
- Staff receive the expected fault and restore messages
7. Build the Human Response Into the Test
Technology detects the problem. People limit the damage.
For each high-priority alarm, the written response should identify:
- Who receives the first notification
- Who is called if there is no acknowledgement
- How the recipient enters the building
- Where the room is located
- What can be shut down safely
- Where water and equipment isolation points are located
- Which contractor or emergency service should be called
- What must not be reset before investigation
- How the event is documented
Test the procedure with a tabletop exercise. Ask the after-hours contact to explain what they would do after receiving “low temperature—sprinkler room” at 2:00 a.m. If the answer depends on calling someone whose number is not available, the response plan is incomplete.
The article 7 Areas Every Commercial Building Should Be Monitoring 24/7 can help facility teams identify other spaces that need an assigned response.
The Canadian Edge: Winter Changes the Failure Sequence
Autumn: Remove Grit and Confirm Placement
Before freezing weather, check sensors that may have been moved during cleaning, storage or summer work. Clear floor-level flood devices without placing them where routine washing will create nuisance alarms.
Early Winter: Watch Exterior Openings
Door contacts begin showing alignment problems as seals stiffen and metal contracts. Salt and moisture collect around thresholds. An opening that fails to latch can expose the building to both unauthorized entry and freezing air.
Deep Winter: A Small Temperature Drop Can Become a Water Loss
At -30°C, a failed heater, open damper or unsealed door can cool a vulnerable pipe space quickly. The temperature alarm must provide enough time for the after-hours contact to reach the building and correct the cause.
Freeze-Thaw Periods: Water Appears After the Cold Event
Damage may occur during the freeze, while the leak appears later during thawing. Keep flood monitoring active after temperatures recover. Do not close a temperature event without checking nearby piping and equipment.
Canadian Code and Accessibility Considerations
Fire alarm and smoke or heat detection requirements depend on the building, occupancy, approved system and Ontario Fire Code. A general-purpose environmental sensor or security-system heat detector is not automatically a substitute for a required fire alarm device.
Ontario’s Fire Code requires fire-safety devices to be maintained and sets inspection and testing duties for fire alarm systems. Required work should be completed by qualified personnel using the applicable standard and approved documentation. Review the Ontario Fire Code.
The 2024 Ontario Building Code came into effect on January 1, 2025. New work involving alarms, controls, accessible routes or connected door systems should be reviewed against the requirements applying to that project. Review Ontario’s current Building Code.
CSA/ASC B651:23 addresses accessible design in the built environment. Detection-system panels, cabinets, conduit and service equipment should not reduce the required clear width of an accessible route or block controls intended for public use.
The Accessible Canada Act applies to federally regulated organizations. It does not create a general detection-system requirement for every Ontario property, but federally regulated building teams must consider barriers in the built environment and information and communication technologies.
Pre-Winter Detection-System Checklist
Inventory and Placement
Confirm every sensor and zone location
Update room names and panel labels
Compare the inventory with current drawings
Check for renovations or equipment changes
Verify flood sensors follow likely water paths
Check temperature sensors against airflow and exterior walls
Functional Test
Use the approved test method for each device
Confirm the panel receives the correct zone
Verify time, date and event description
Confirm the device restores normally
Record test results and deficiencies
Arrange qualified fire alarm testing where required
Notifications and Response
Test local and remote notifications
Confirm monitoring-station receipt
Update the contact and escalation list
Verify after-hours building access
Review water and equipment shutoff instructions
Complete a tabletop response exercise
Power and Communication
Test panel batteries and UPS equipment
Confirm network equipment has backup power
Check internet and cellular communication paths
Review battery age and replacement dates
Confirm automatic recovery after an outage
Verify that no tested zone remains bypassed
Frequently Asked Questions
Is a green light enough to confirm that a sensor works?
No. It may show that the device has power or is connected. A controlled activation test is needed to confirm that the condition is detected and the alert reaches the right person.
Where should a flood sensor be installed?
It should be placed where water is likely to travel first, based on equipment, pipe joints, floor slope, drains and barriers. A sensor on a raised pad may not detect water spreading across the floor.
What temperature should trigger a low-temperature alarm?
There is no single setting for every room. The threshold depends on piping, equipment, normal room conditions, sensor position and how long the response will take.
Are heat detectors and temperature-monitoring sensors the same?
No. A fire-system heat detector is designed and approved for fire detection. A temperature-monitoring sensor tracks environmental conditions. Do not substitute one for the other without a qualified code and system review.
Why do door contacts cause more alarms in winter?
Cold can stiffen seals and contract metal, while ice and salt prevent full closure. The magnet and contact may then sit outside their permitted alignment or gap.
Should sensors be tested after renovations?
Yes. Walls, shelving, equipment, airflow and room use may have changed. Verify placement, labels, thresholds and the response procedure before relying on the system.
Schedule a Pre-Winter Detection-System Test
If flood, temperature, door or motion alarms have not been tested through to the final recipient, arrange the work before the first extended freeze.
ACS Systems installs and services detection and monitoring systems across Toronto and the GTA. Testing can include devices, panel zones, notification paths, monitoring connections, backup power and staff response information. Connected commercial alarm systems can be reviewed at the same time.
Contact ACS Systems to schedule a building detection-system review.
Trust Note From ACS Systems
This article provides general guidance for commercial, institutional and multi-residential properties. Fire alarm, detection, electrical, accessibility and monitoring requirements vary by building, occupancy, equipment and approved design. Required systems should be inspected and tested by qualified personnel under the codes, standards and manufacturer instructions that apply.
