Troubleshooting
Hot Water Temperature Keeps Changing
The classic hot-cold-hot shower problem.
Hot water that swings between hot and cold — often called the 'cold water sandwich' — is a common combi complaint. It can stem from low flow triggering the burner to cut out, a scaled heat exchanger, a worn flow sensor, or a diverter valve that's slow to respond.
A technician can pin down which component is causing the swing and correct it.
Why temperature fluctuates
- Flow rate dropping below the burner's minimum
- Scaled heat exchanger reducing transfer
- Worn flow sensor misreading demand
- Sticky diverter valve
- Very short hot-water draws
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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