Troubleshooting
Radiators Not Heating Evenly
Cold spots usually mean air or sludge, not a broken boiler.
If some radiators stay cold while others get hot — or a radiator is warm at the bottom but cold at the top — the boiler itself is often fine. The usual culprits are trapped air, a sludge buildup, or balancing issues in the heating loop.
Bleeding a radiator is a common homeowner task, but persistent cold radiators, or cold-at-the-bottom radiators (which indicate sludge), usually need a power flush or system service.
Common causes
- Trapped air (cold at the top — bleed the radiator)
- Sludge buildup (cold at the bottom — needs a flush)
- Unbalanced system (some rooms hot, others cool)
- Failed thermostatic radiator valve
- Pump unable to push flow to far radiators
This is not a DIY repair
Combi boilers are gas-fired appliances regulated under the BC Safety Standards Act. Opening the unit, touching the gas valve, or working on the flue without a valid BC gas-fitter licence is both unsafe and illegal. Diagnosing the fault is helpful — fixing it should always be left to a certified technician.
Call 778-909-5731Related symptoms & help
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