Heat Pump Glycol Antifreeze
Why Maintenance Matters
A common problem we find in heat pump systems is insufficient Glycol Antifreeze. Here we answer some of the most common questions about Glycol Antifreeze in air to water Heat Pump System, including what happens if the glycol antifreeze levels are too low? And how much antifreeze should be in the heating system?
Ensuring that the glycol antifreeze levels align with the manufacturer’s guidelines helps your heating system run safely and efficiently during the colder months.
Glycol Antifreeze Fluid for Heat Pumps
Why is Glycol Antifreeze Important?
Maintaining the correct glycol level in your heating system is important for several reasons:
Freeze Protection: Glycol lowers the freezing point of the fluid, preventing it from freezing in low-temperature environments and avoiding breakdown when you need the system the most.
Corrosion Resistance: Glycol solutions often contain corrosion inhibitors that protect the system components from corrosion and prolong their lifespan.
Heat Transfer: Glycol solutions have excellent heat transfer capabilities, making them ideal for use in heating systems.
Regularly checking glycol antifreeze will help ensure the system’s performance and longevity.
Our team make sure that the levels meet the manufacturer’s recommendations, ensuring your heating system operates safely and efficiently during the colder months.
Why is there Glycol Antifreeze in my Heat Pump System?
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.
What happens if I have no antifreeze in my heating system?
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 Ethylene Glycol Antifreeze also has inhibiting properties meaning that it prevents corrosion of the ferrous materials in the heating system.
How much antifreeze should be in my 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. This is less than 5% of the total volume of an average system and is one quarter of the total volume of glycol required in the average home. The effect of adding such a small amount of antifreeze is very little impact on the system freeze point.
How often do I need to top up glycol antifreeze in my heat pump system?
Glycol degrades 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. Over time ethylene glycol can degrade into glycolic acid so pH levels also require monitoring as the system ages.
