Heat pumps and air conditioning systems are integral parts of a building’s operation through the role they play for people and product development.

Heat pumps are a cost effective and efficient way of providing heating, cooling (only in reversible systems) and hot water, while air conditioning also provides heating and cooling. Both can ensure occupant comfort, a clean air environment and critical cooling.

This video displays a recent heat pump maintenance visit to site, where our service engineer found coils covered in frost. This should not occur in normal operation.

Causes of ice or frost on coils or pipes

1. F-Gas (refrigerant gas) leak

The part of the system that contains the F-Gas is a closed system, therefore, no gas gets used up and none should escape.

Frost or ice can appear on coils and pipes if an F-Gas leak occurs. A leak can cause a drop in system pressure, as less gas than expected passes through the refrigeration cycle. As each heat pump or air conditioning system is optimised for a specific volume of F-Gas, if a lower than expected volume passes through it will eventually result in a system failure.

2. Dirty or blocked filters

Filters are designed to protect surfaces of air conditioning systems from becoming dirty.

If filters become blocked or dirty, less air than expected is pulled through the air conditioning system. The volumes of F-Gas and air are no longer at optimal levels. This can result in frost or ice appearing on air conditioning coils or pipes.

3. Fans

Fans equally play an important role in the heating and cooling process in heat pumps and air conditioning systems.

These systems rely on a continuous supply of air which fans pull through heat pumps and air conditioning units. If the fan is not operating correctly, a reduced air volume will present a problem for the F-Gas. This will result in coils or pipes containing a frost or ice.

Implications for facility managers

Being proactive, noticing and acting on issues such as frosted or iced coils or pipes can save undue, waste, worry and downtime in the following ways.

1. Energy waste

In the case of dirty or blocked filters, a fan has to work harder to pull air through the system due to the resistance or blockage. A harder working fan thus expends more energy, resulting in unnecessary energy waste.

2. F-Gas leak prosecution and penalties

A fine of up to € 500,000 or 3 years’ imprisonment or both can result from non-compliance with F-Gas regulations on leak checking, emissions prevention and other measures, in accordance with Irish law – S.I. No. 658/2016 – European Union (Fluorinated Greenhouse Gas) Regulations 2016. This statutory instrument implements the overarching European legislation – Regulation (EU) No 517/2014.

3. Human resource (HR)/industrial relations (IR) complaints

Occupants complaining of uncomfortable conditions with insufficient heating, cooling or hot water. These issues could lead to reduced productivity or cause a staff walk-out.

4. Business continuity

Failure of critical heat pump or air conditioning systems could result reputational damage from plant downtime and as a result, reduced productivity or business closure.

5. Environmental consequences

Older heat pump and air conditioning systems may contain F-Gases that are classified as ozone depleting substances (ODS). ODS are chemicals that can damage the earth’s ozone layer if they were to escape into the upper atmosphere, therefore leaks could be extremely harmful to the ozone layer.

Historically, R12 and R22 were widely used ODS F-Gases. Servicing and maintaining all systems containing ODS F-Gases have been banned on since 01 January 2015.

While most of today’s widely used F-Gases don’t damage the ozone layer, some do contribute to global warming. Therefore, any escape of these gases could have severe environmental consequences.

Planned preventative maintenance (PPM)

PPM is a risk adverse measure that maintains systems such as heat pump and air conditioning plant at set intervals to decrease the risk of failure. PPM is a proven cost-effective solution, providing comfortable conditions that support your business needs, as unmaintained plant will eventually fail to function, become troublesome or perform at levels that are inefficient.

View further information on HVAC and heat pump maintenance.