BoilerBuying Guide2026-03-10
Combi Boiler Not Enough Hot Water
Insufficient hot water usually means undersizing, scale or low flow — diagnosable and fixable.
If your combi can't keep up with hot-water demand, a few causes are likely.
Sizing and scale
An undersized combi or one scaled up in hard water can't deliver enough hot water, especially with multiple outlets running.
What to do
Descaling restores a scaled unit; if it's genuinely undersized for your home, we'll recommend the right capacity.
Key takeaways
- Undersizing is a common cause
- Scale reduces hot-water output
- Descaling can restore it
- We size correctly at replacement
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Licensed, gas-certified technicians serving Greater Vancouver since 1999. CombiBoiler.ca — A division of ROMA Heating Ltd..
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