What Our Glycol Service Includes
Glycol concentration test (refractometer) — freeze protection level
pH test — acidic glycol corrodes heat exchangers
Inhibitor level test — prevents internal corrosion
Visual inspection for discolouration and sludge
Full system flush if glycol is degraded or contaminated
Recharge with correct inhibited propylene glycol mix
System pressure test after flush and refill
Purge and bleed to remove air from all zones
Documentation of glycol spec, concentration, and service date
Compatible with all boiler brands — Navien, NTI, Viessmann, Weil-McLain
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📞 647-699-2474Our Repair Process
- Glycol sample and testing — we draw a sample from the system and test freeze point concentration with a refractometer, and pH and inhibitor level with chemical test strips.
- Pass or fail — if concentration is adequate (typically -30°C or lower for Ontario) and pH is in range (7.5–10.5) and inhibitors are active, we document and you're good for another 2 years. If any parameter fails, we recommend a flush.
- System flush — we drain the system completely, flush with clean water to remove degraded glycol and any sludge, and inspect the drained fluid for signs of corrosion or contamination.
- Recharge with inhibited glycol — we refill with the correct concentration of inhibited propylene glycol (never automotive antifreeze — the inhibitors are wrong for hydronic systems).
- Purge and test — we purge all air from the system zone by zone, restore correct operating pressure, and run the boiler through a full heat cycle to confirm proper circulation.
Common Questions
Automotive antifreeze (ethylene glycol) should never be used in a boiler system. It contains silicate-based inhibitors designed for aluminum engine blocks — not copper tubing, stainless heat exchangers, and brass fittings. Hydronic systems require inhibited propylene glycol with corrosion inhibitors specifically formulated for boiler materials. Using the wrong product can void your boiler warranty and cause rapid internal corrosion.
Signs include: discoloured (brown or black) fluid when you drain from a purge valve, the system is over 5 years old with no glycol service on record, a recent boiler or component replacement that opened the system, or unexplained pressure loss suggesting internal corrosion. The safest approach is to test — we bring the testing equipment and give you a pass/fail answer on the spot.
Glycol in a boiler system isn't just about freeze protection — the inhibitors prevent internal corrosion of metal components. Even if your mechanical room never freezes, degraded glycol without adequate inhibitors will corrode your heat exchanger, pump components, and zone valves from the inside. Many Navien warranty claims are denied because of degraded glycol causing heat exchanger failure.
Every 4–5 years is standard. York Region's water is moderately hard — especially in Vaughan, Richmond Hill, and Markham — which can accelerate inhibitor depletion. If your system has had any components replaced that required draining, the glycol should be tested after the repair. We recommend testing at every annual maintenance visit.
Yes — and Navien is aware of this. Acidic glycol (pH below 7.0) attacks the primary stainless steel heat exchanger and the secondary copper heat exchanger on NCB combi units. Navien Canada has seen warranty claims denied specifically because glycol was found to be acidic or the wrong type. Maintaining correct glycol is one of the most cost-effective things you can do to protect a $3,000–$5,000 Navien unit.
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