Need urgent heat pump repairs? At Banshee Boilers, our approach includes preventative maintenance, prompt repairs, and comprehensive inspections to ensure your heat pump operates efficiently and safely.
Waterlogged potable expansion vessels are a common issue in newer homes with Booster Pumps.
Potable Expansion Vessels accommodate expanding water, and pressure fluctuations. If the vessel becomes filled with water it can no longer perform its function.
Although these Potable expansion vessels are technically NOT a part of the heating system, typically they are supplied with the Heat Pump along with an Inlet Group manifold. These parts may be covered under some Heat Pump Manufacturer warranties.
Repressurising or replacing the vessel ensures your heating system runs efficiently and safely.
They are usually beside your water cylinder or indoor Heat Pump unit. The potable expansion vessel is usually white, grey, or blue. The label on the side of the potable vessel will say “POTABLE” or have an icon of a Tap.
You may also see a red vessel which is typically the heating vessel. The heating vessel rarely becomes waterlogged in low-temperature heat pump systems.
Commonly, as a potable expansion vessel loses its pressurised air charge it can start making strange noises that sound like loud banging or groaning.
Often a fully waterlogged potable vessel will not make any such sound however, repressurising an expansion vessel that has been waterlogged can sometimes cause it to vibrate or groan when boosted water is used. Repressurising might only restore its functionality temporarily and the vessel may have to be replaced. If your vessel has been waterlogged for a while, your pressure relief valve may be dripping and may also have to be replaced.
There are a few other reasons these sounds can happen:
Gently tap the vessel. A properly functioning vessel will produce a hollow ringing sound while a waterlogged vessel will produce a dull thud.
Repressurising or replacing a waterlogged potable expansion vessel is crucial for several reasons:
Motorised valve failures are common in newer heating systems.
Motorised valves open and close to allow or prevent the flow of water. They have a valve body (connected to plumbing) and an actuator (the motor). When they receive an electrical signal they activate. They can control heating zones and hot water demand, and can be either a two-port (single circuit) or three-port (dual circuit) valve.
Control Flow: It opens and closes to control the flow of water to different parts of your heating system, such as the radiators, underfloor heat circuit or hot water coil.
Zone Control: In systems with multiple heating zones, motorised valves allow independent control of heating for each zone. This means you can heat specific areas of your home without heating others.
Automation: These valves are typically connected to your heating system’s thermostats or Heat Pump Controller, allowing for automated control of the heating, improving efficiency and comfort.
Faulty Actuator: The actuator, which is the motor section mounted on top of the valve, is the most common cause of failure. If it has seized up or is worn, your heating system may start showing intermittent or constant water flow errors or entire zones may stop heating altogether.
Seized Valve: If the valve itself has seized up and is difficult or impossible to move, it needs to be replaced.
Leaking Valve: A worn valve that is leaking will also need to be replaced to prevent further damage to your heating system.
Manual Override Issues: If the manual override lever is difficult to move or doesn’t work, it could indicate a problem with the valve or actuator.
Topping up the glycol in your heating system is important for several reasons:
Regularly checking and topping up the glycol will help maintain the system’s performance and longevity.
Our team will make sure that the levels meet the manufacturer’s recommendations, ensuring your heating system operates safely and efficiently during the colder months.
Glycol antifreeze is only required in Monobloc Heat Pump systems. In these systems all the refrigerant and refrigeration equipment is hermitically sealed by the manufacturer and located in the outdoor unit. Water from your heat emitters (radiators or underfloor circuits) and hot water coil are plumbed to and pumped through the heat exchanger in this outdoor unit.
If water alone is circulating in a monobloc system and the outdoor temperature drops to 0° or below, this water can freeze in the pipes or the heat exchanger. This will result in flow errors on the heat pump controller and no heating or hot water can be produced until the system thaws out.
Liquid freezing inside the heat exchanger could cause it to expand, resulting in the total destruction of the outdoor unit. For this reason some manufacturers will void the warranty on your Heat Pump if insufficient Glycol Antifreeze levels are found.
Water alone circulating in the heating system will cause the insides of your radiators to corrode and rust, leading to extensive damage. C20 Glycol Antifreeze also has inhibiting properties meaning that it prevents corrosion of the ferrous materials in the heating system.
In Ireland, manufacturers recommend a mixture ratio of 20:80 of antifreeze to water by volume. This will give a freeze point of between -7°C or -8°C when the mixture liquid is tested. This temperature range is unlikely to be sustained for a prolonged period in this climate.
EXAMPLE: If a heating system consists of a buffer tank, pipework, radiators and/or underfloor circuits with a total volume of 130 litres, we need to mix 26 Litres of C20 Ethylene Glycol Concentrate with 104 Litres of water to meet the manufacturer’s requirement for a freeze point of -7°C or -8°C.
It is very common to find that glycol levels are insufficient and the leading causes of this are installer error at commissioning, amendments to the heating system and leaks.
It’s worth noting that some service providers might only add between 1 to 5 litres when attempting to refill the Glycol Antifreeze, which is less than 5% of the total volume of an average system. This is not sufficient as it is one quarter of the volume required in the average home.
Glycol degrades very slowly in a heating system and topping up the glycol is not a regular task. If the correct amount of glycol is in your system and there are no losses due to leaks or other invasive plumbing works, the system will maintain the required freeze point for at least 5 or 6 years. During your annual heat pump service, this will be checked and recorded on your service report.