Plumbers In Lincoln

Frequently Asked Questions

• What pressure should my boiler be running at?

  For most modern combi and system boilers, the pressure when the heating is off should sit between 1.0 and 1.5 bar on the gauge. When the heating is on, it is normal for this to rise slightly to around 2.0 bar. If the pressure drops below 0.5 bar the system has lost water and will need repressurising. If it rises above 2.5 bar this can indicate a fault with the expansion vessel or pressure relief valve, and a qualified engineer should be called.

• Why is my radiator hot at the bottom but cold at the top?

  This is almost always caused by trapped air in the radiator preventing hot water from circulating properly to the top. The solution is to bleed the radiator using a radiator key, which releases the trapped air. After bleeding, always check your boiler pressure gauge as bleeding can cause a drop in system pressure that will need topping up.

• What is a power flush and how do I know if my system needs one?

  A power flush is a deep cleansing process that pumps water at high velocity through your central heating system to remove built up sludge, rust and debris from inside the pipes, radiators and boiler.
  
  Signs that your system may need a power flush include radiators that take a long time to heat up, cold spots at the bottom of radiators, a noisy boiler or pump, and rooms that are consistently colder than others. A properly carried out power flush should last between five and ten years, provided a corrosion inhibitor is added to the system afterwards.

• Why does my boiler keep losing pressure?

  A boiler that repeatedly loses pressure usually indicates one of three things. The most common cause is a small leak somewhere in the system, either in the pipework, radiator valves or the boiler itself. It can also be caused by a faulty expansion vessel that is no longer able to absorb the pressure created when water heats up, or by a pressure relief valve that is releasing water. If your boiler loses pressure more than occasionally, it should be inspected by a Gas Safe registered engineer.

• What is the difference between a combi boiler, a system boiler and a regular boiler?

  A combi boiler heats water on demand directly from the mains, meaning there is no need for a separate hot water cylinder or cold water tank in the loft.
  
  A system boiler works with a hot water cylinder to store heated water but still connects directly to the mains, making it a good choice for homes with multiple bathrooms. A regular boiler, sometimes called a heat only or conventional boiler, requires both a hot water cylinder and a cold water tank in the loft and is typically found in older properties.
  
  The right choice for your home depends on the size of the property, the number of bathrooms and the existing pipework.

• What causes banging or knocking sounds in my pipes?

  Banging, knocking or rattling sounds in pipework are commonly referred to as water hammer. This can be caused by trapped air in the system, water pressure that is too high, or loose pipe fittings that move when water flows through them.
  
  A rumbling or popping sound from the boiler itself can indicate limescale buildup inside the heat exchanger, which restricts water flow and causes the water to overheat locally. These sounds should not be ignored as they can indicate issues that will worsen over time if left untreated.

• How often should my boiler be serviced?

  A boiler should be serviced by a qualified Gas Safe registered engineer once a year. An annual service includes a visual inspection for leaks or corrosion, a gas pressure check, a flue test to check for harmful emissions, and an inspection of the boiler controls. Regular servicing keeps the boiler running safely and efficiently, can identify small issues before they become costly repairs, and is often a requirement of the boiler manufacturer's warranty.

• Why is there no hot water even though my heating is working?

  On a combi boiler this is often caused by a faulty diverter valve, which is responsible for directing hot water either to the radiators or to the hot water taps. If the valve sticks or fails it can result in heating working normally while hot water to the taps is lost.
  
  On a system with a hot water cylinder it could indicate a failed immersion heater, a faulty thermostat on the cylinder, or an issue with the motorised valve. Our heating engineer will be able to diagnose the fault quickly and advise on the most cost effective solution.

• What causes low water pressure in my home and how can it be fixed?

  Low water pressure can be caused by several things including limescale buildup inside pipes, a partially closed stopcock, a leak somewhere in the system, or simply low pressure from the mains supply. If the low pressure affects only one tap it is likely a localised blockage or faulty fitting.
  
  If it affects multiple outlets throughout the property it may point to an issue with the incoming supply or a hidden leak. A plumber can carry out a pressure test to identify the cause and recommend the appropriate course of action.