Phase 1: Electrical System Verification
Run these checks on a dry day each fall, before the first snowfall. A thirty-minute check prevents a blizzard-morning failure.
| Step | Check | Pass Standard |
|---|---|---|
| 1 | Junction boxes — inspect every box for watertight seals, clean terminations, tight connections | No moisture, no corrosion, no loose lugs |
| 2 | Cold leads — verify conduit protection where leads emerge from the slab | Conduit intact, no exposed wiring |
| 3 | Conductor resistance — digital multimeter, compare to the CSA label value | Within -5% to +10% (some models ±15%) |
| 4 | Insulation resistance — 500 VDC megohmmeter (Megger) test | Infinite ohms — any reading means a breach |
| 5 | GFEP breaker — confirm a dedicated 30mA trip breaker per circuit (NEC) | 30mA GFEP, not a 5mA GFCI |
| 6 | Amp draw test — measure the live current per circuit | 15A breaker → max 12A; 20A → 16A; 30A → 24A; 40A → 32A |
| 7 | Trigger voltage — verify the control relay panel | Clean signal, no voltage drop |
Phase 2: Hydronic System Checks
| Check | What to Look For |
|---|---|
| Glycol concentration | Freeze point must beat the coldest local design temperature; 30–50% propylene glycol |
| Fluid condition | Check pH (corrosion), degradation, and impedance buildup in the mixture |
| Loop flush | Flush if the fluid is dirty or the pH is off |
| Boiler & pump operation | Fire the boiler, confirm pump circulation, listen for air in the lines |
| Controls & sensors | Test automatic sensors; confirm the 38–39°F + moisture trigger logic |
| Pressure test | Hold system pressure; any drop = a leak to find before winter |
Phase 3: Surface & Site Checks
- Surface condition: inspect for cracks, spalling, or paver settling that could stress embedded elements
- Drainage: confirm meltwater paths are clear — standing water refreezes into the exact hazard the system exists to prevent
- Sensor surfaces: sensors must be flush and exposed — clear debris, leaves, or snow buildup off the sensor zones
- Record everything: keep the resistance/insulation readings in a log — the year-over-year trend is the early warning system
The math that matters: variance = (measured − nominal) ÷ nominal × 100. Log it, date it, keep it — a drift toward the edge of the ±10% window is the first sign of a degrading element, and the only cheap moment to act is before the surface is buried under a foot of snow.