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Boiler Losing Pressure? Here’s Why

07/22/2020 12:54 pm


Combi boilers need constant water pressure. To help you stay calm under (low) pressure, below are some of the most common reasons & fixes:

  • Leak in the pressure relief valve

Debris may have got lodged inside. Valve has to be replaced or cleaned.

  • Expansion vessel is faulty

If there’s an issue in the expansion vessel, it won’t be able to handle the expanding hot water. You’ll need an expert to do a pressure check.

  • Air in combi boiler system

Find the radiator bleed valve and slowly turn the valve counterclockwise until water starts dripping out. This will release trapped air and let hot water into the cold fins. If bleeding the radiators doesn’t work, contact a technician. You may have a bigger issue such as air lock in the system. 

  • Leak in the your central heating system

Look for signs of leakage such as a stain on your ceiling, a damp floor, leaky pipes, or a small hole in a radiator. A leak may be located in corroded pipes and radiators.

How does a combi boiler work?

There are 3 types of boilers: regular, system, and combi. While regular and system boilers need a cylinder to store hot water, combi boilers heat water from the mains. Basically, a combi boiler is a combination of a water heater and central heating boiler in one compact unit. For it to work as efficiently as possible, your water pressure needs to be stable.

A combi boiler heats cold water that flows around a circuit of pipes and radiators through your home, and produces hot water when you turn a tap on, or when it detects the household is below than the preset temperature. It responds automatically by sending hot water to the required tap, or firing up the central heating, which means that hot water is available 24/7.

Combi boilers are preferred in the majority of new boiler installations in Canada because of their high energy efficiency, convenience, and compact size. The best combi boiler, such as Navien, will deliver plenty of hot water for your showers, baths, and sinks, and will keep your radiators piping hot throughout the coldest of winters.


Read more

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