Boiler support
Installation, repairs and servicing
Common questions about boiler faults, annual checks, replacement options and system protection.
Advice
Frequently asked questions
Common questions about boilers, heat pumps, smart controls, hot water cylinders, powerflushing, and plumbing — answered by our Gas Safe registered engineers.
BoilersInstallation, repairs and servicing
Heat pumpsDesign, sizing and commissioning
System careControls, cylinders and powerflushing
Low-carbon heating
Heat pumps and controls
Practical guidance on sizing, low-temperature heating design, smart thermostats and zoning.
System care
Cylinders and powerflushing
Answers about hot water performance, unvented cylinders, sludge, magnetic filters and long-term heating protection.
Boiler Repairs
My boiler keeps losing pressure — what could cause this?
Pressure loss is one of the most common boiler problems. Frequent causes include a small leak in the system, a failing pressure relief valve, or a faulty expansion vessel. Topping up the pressure temporarily is fine, but if it needs doing regularly, the underlying cause should be diagnosed and fixed.
My boiler is making a banging or rumbling noise — what does that mean?
Banging, kettling, or rumbling noises usually point to limescale or magnetite sludge build-up on the heat exchanger. This makes the boiler work harder, increases gas consumption, and accelerates wear. A boiler service and, where needed, a system powerflush can resolve this.
Should I repair or replace my boiler?
The right answer depends on the boiler's age, repair cost, and the frequency of past problems. A boiler under ten years old with a straightforward fault is usually worth repairing. An older boiler with recurring faults may be more economic to replace. We give honest advice on both options.
My radiators are not getting hot — what could cause this?
If all radiators are cold, the boiler may have locked out or the pump may have failed. If some radiators are cold and others are hot, common causes include air in the system, a blocked TRV, or sludge restricting flow. Cold spots at the bottom of a radiator specifically suggest magnetite sludge.
Boiler Servicing
How often should a boiler be serviced?
Most manufacturers recommend annual boiler servicing. Having your boiler serviced once a year by a Gas Safe registered engineer maintains efficiency, reduces breakdown risk, and helps to satisfy manufacturer warranty requirements.
What does a boiler service include?
A thorough service covers visual inspection of the boiler, flue, and pipework; burner and heat exchanger cleaning; combustion analysis; gas pressure and rate checks; safety device testing; expansion vessel assessment; pump and controls checks; condensate trap inspection; and checks of any magnetic filter and inhibitor levels.
Will having my boiler serviced reduce my gas bills?
A boiler that is serviced regularly maintains its designed efficiency. As components become dirty or fall out of calibration, efficiency drops and gas consumption rises. Regular servicing, clean system water, magnetic filtration, and correct inhibitor levels all contribute to lower running costs over time.
Boiler Installation
What type of boiler is right for my property?
The best boiler type depends on your property size, number of bathrooms, current hot water setup, and existing pipework. Combi boilers suit many smaller homes. Larger homes with multiple bathrooms often benefit from a system or regular boiler with a hot water cylinder. We assess the property before recommending an option.
Do I need a system flush before a new boiler is installed?
In many cases, yes. Older heating systems often contain magnetite sludge and corrosion debris. Installing a new boiler into a contaminated system risks damaging the new heat exchanger. We check system condition during the survey and advise honestly on whether a flush is needed.
Can you install any make of boiler?
We install boilers from a range of leading manufacturers. As Worcester Bosch Accredited Installers, we have particular expertise in the Worcester Bosch range and can offer extended warranty benefits available through that accreditation. If you have a brand preference, we are happy to discuss it.
Heat Pumps
What is an air source heat pump?
An air source heat pump extracts thermal energy from outdoor air and transfers it into your home's heating system using refrigeration cycle technology. It moves existing heat energy rather than burning fuel, and modern systems can extract usable heat even during cold UK winter temperatures.
How efficient are heat pumps?
Heat pump efficiency is measured by Coefficient of Performance. A well-specified and correctly installed heat pump can deliver several units of heat for every unit of electricity it consumes. Actual efficiency varies with outdoor temperature, system design, and how well the heat pump is matched to the property's heat loss.
Are heat pumps suitable for older properties?
Heat pumps can work well in older properties, but they need careful assessment. Because they operate at lower flow temperatures than gas boilers, they work best with larger heat emitters and good insulation. We carry out a full heat loss assessment before recommending any system.
Smart Controls
What is a smart thermostat?
A smart thermostat connects to your home's Wi-Fi and lets you control heating remotely via a smartphone app. Unlike a standard programmable thermostat, many smart systems can learn schedules, respond to routine changes, and provide useful heating usage information.
Can I control my heating remotely?
Yes. A smart thermostat with a companion app lets you adjust your heating from anywhere with a phone signal or internet connection. Some systems also allow remote control of individual room temperatures where smart radiator valves are installed.
What is zoned heating?
Zoned heating divides your home into separate areas that can be heated independently. Rather than heating every room to the same temperature on the same schedule, zones let you warm only the spaces in use, reducing energy waste.
Powerflushing
How do I know if my system needs a powerflush?
Common indicators include cold spots at the bottom of radiators, slow radiator warm-up, boiler kettling or rumbling noises, dirty water when radiators are bled, and higher gas bills without a clear reason. We assess the system first to confirm powerflushing is the right solution.
Will powerflushing damage my boiler or radiators?
When carried out correctly on a suitable system, powerflushing does not damage a boiler or radiators. Very old or weakened systems may not be suitable, which is why we assess the system first and discuss our findings before work begins.
What is a magnetic filter and do I need one?
A magnetic filter is fitted inline on the heating circuit and captures iron oxide particles as heating water circulates. It is cleaned at every service. Many boiler manufacturers recommend or require magnetic filtration, and after a powerflush it is strongly recommended to prevent sludge rebuilding.
Heating and plumbing engineers serving Bristol, Bath, and the surrounding areas
Hot Water Cylinders
What is the difference between a vented and unvented cylinder?
A vented cylinder relies on a cold water storage tank and delivers hot water under gravity pressure. An unvented cylinder connects directly to the mains supply and delivers hot water at mains pressure, giving stronger showers and better flow rates. Unvented systems require a G3 qualified engineer.
Can I upgrade to an unvented cylinder?
In most cases, yes, provided the incoming mains water supply has sufficient pressure and flow rate. We check this as part of the survey. In some older properties or those with shared supply pipes, additional work may be needed or the system may not be suitable.
Why does a heat pump need a different hot water cylinder?
Heat pumps produce hot water at lower temperatures than gas boilers. Standard cylinder coils are sized for boiler temperatures and may not transfer heat fast enough. Heat pump cylinders have larger coils with greater surface area, keeping the heat pump efficient and improving hot water recovery times.
Still not found the answer?
Get in touch with the details of your heating or plumbing question and we will point you towards the right next step.