Consequences of cyclones; risks of HVAC&R equipment.

Auckland, New Zealand – April 12, 2017
Consequences of cyclones; risks of HVAC&R equipment.

The Climate Controls Companies Association New Zealand (CCCANZ) is advising homes and businesses to take important safety measures with regards to heating and cooling systems, after severe flooding continues to affect areas of New Zealand. Buildings exposed to flooding and water damage can affect heaters, furnaces, boilers, air-conditioning, ventilation, heat pump and refrigeration systems – putting people at risk.

 “Many people may not understand the need to replace flood-damaged air conditioning, heating and refrigeration equipment,” says Matthew Darby from the Climate Controls Companies Association (CCCANZ). “From their point of view, their A/C, heating or refrigeration system has dried out and appears to be fully operational. However, damage is not always going to be apparent. We advise people to play it safe and replace, rather than repair flood-damaged heating, cooling and water heating equipment.”

The storm has affected Auckland and Wellington with major downpours, flooding and slips, creating serious impacts in the Bay of Plenty, where around 2000 residents were forced out their homes in Edgecombe. A state of emergency has been declared in Whakatane and the Bay of Plenty. Heavy rain and thunderstorms are expected again this week, as Cyclone Cook moves across the country with severe weather warnings in several parts of the country.

“HVACR equipment that has been affected by standing water will typically be damaged beyond cost effective repair, with fully submerged equipment requiring replacement of all exposed electrical components and motors, "says Mr. Darby. “There is also potential health issues such as mould and disease caused by contaminated floodwaters.”

“If there is any question flood water has reached heating and cooling systems, including domestic appliances such as heat pumps and refrigerators or freezers, equipment should be checked by a qualified professional. If you are concerned about receiving the right advice, look for a company that is a member of the CCCANZ and whose people are accredited though the Institute of Refrigeration, Heating and Air Conditioning Engineers (IRHACE). This is particularly important for commercial and industrial businesses where issues with mould may not be apparent and through cleaning and inspection is required.”

To support businesses and homeowners, the Industry Center has produced a guide to the impacts of flooding for HVAC&R in residential and commercial areas available at website.  click here

About the Climate Controls Companies Association New Zealand (CCCANZ):

CCCANZ is the industry association for Heating, Ventilation, Air Conditioning, and Refrigeration (HVAC&R) companies in New Zealand.  CCCANZ's purpose is to:

  • Promote high standards of business competence and industry conduct for companies engaged in climate controlled environments
  • Promote the advancement of education, practice, and technology in HVAC&R
  • Promote the continuing improvement of standards in the HVAC&R industries
  • Represent and promote the interests of members
  • Provide for the adjudication and arbitration of disputes between members and the public
  • Promote a standard of workmanship and design for members to adhere to.

Matt Allfree
CCCANZ Administration Office
Unit 5/42 Ormiston Road, Flat Bush
Auckland 2016
New Zealand
Ph: 09 273 0044

Dealing with Disaster: The impact of flooding on HVAC&R systems in Residential Homes.

Floods and HVACR Equipment

After a flood or storm surge from a cyclone, homeowners need to take important safety precautions with regards to their home’s heating and cooling systems. A house or basement exposed to standing water can damage your home’s water heater, furnace, boiler, air-conditioning, ventilation, and heat pump system — putting your family at risk. Before touching any electrical equipment ensure your power is shut off and you are protected from any risk of electrocution.

Replace, Don’t Repair

Flood-damaged heating and cooling equipment and systems should be replaced and not repaired, according to the CCCANZ and IRHACE. All inspection and replacement work on flooded equipment should be performed by qualified heating and cooling professionals, not by homeowners. Unfortunately, equipment damaged by natural disasters is not covered by manufacturer warranties, yet is likely to be covered by insurance; your provider can help you through the claim process. Manufactures should extend customer service and technical assistance as needed to ensure that all customers, service contractors and end users receive any timely support needed.

When looking at replacements, consider new, energy-efficient models that can lower your future energy bills.

Heat Pumps and Air Conditioning (A/C) Systems

Split air conditioning and heat pump systems have power and control wiring between the indoor and outdoor parts of the system, and the piping that moves the refrigerant from inside to outside the home and back.

Even if the system is in contact with flood water for a long period, this sealed system is likely to remain intact. However, if flood water has repositioned either the indoor or outdoor units of a split system by only a small amount, there is the potential for a breached refrigerant system. The heat pump (or air conditioning system) will then require major repair or full replacement.

If the refrigerant system remains intact after the flood, the entire system should be cleaned, dried, and disinfected as mould contamination can be a serious concern. You should have a qualified heating and cooling professional check all electrical and refrigeration connections for both indoor and outdoor units, including all control circuits. The decision to repair or replace should be made by a qualified professional on a case-by-case basis.

Domestic refrigeration and freezers.

As with heat pumps and a/c systems, domestic refrigeration and freezers have power and wiring that can be affected by flooding. Refrigerant is sealed within the system and likely to remain intact however any damage may indicate the appliance needs replacing. Have a qualified heating and cooling professional check all electrical and refrigeration connections for both indoor and outdoor units, including all control circuits. The decision to repair or replace should be made by a qualified professional on a case-by-case basis. If the system is not replaced ensure thorough cleaning and sanitisation is completed before storing any food.

Water Heating Systems

Whether your water heater is gas-fired, oil-fired or electric, if it was exposed to flood water, the unit should be replaced. A new water heater is a relatively small investment, and replacing it is fairly easy to do.

In a gas unit, valves and controls will likely corrode. In an electric unit, the thermostat and controls will likely corrode. In both types, the insulation surrounding the unit will be contaminated and will be nearly impossible to disinfect. Additionally, the insulation would take a long time to dry, leading to corrosion of the tank from the outside.

Even if water heater components have been cleaned and the unit seems to operate properly, parts may corrode in the future. Both gas and electric water heaters have a pressure relief valve that can corrode and stick after being exposed to flood water. Be sure to replace this valve as well.


If you have a central forced-air furnace in the house you are repairing, pay attention to your ductwork too. A professional will not try to salvage duct insulation that has been in contact with flood water, but will replace it because it is impossible to decontaminate. They also will clean, dry and disinfect the ductwork. Doing a thorough job will require disassembling the ductwork. These repairs also give you the opportunity to seal joints in the ductwork and improve insulation to reduce heat loss.

Gas Furnaces and Boilers

If there is any question whether flood water has reached a gas appliance, have the unit checked by a qualified heating professional. Natural gas furnaces, space heaters and boilers all have gas valves and controls that are especially vulnerable to water damage from floods and that damage may not be easy to detect. Corrosion begins inside the valves and controls, and damage may not be readily visible, even if the outside of the device is clean and dry. At a minimum, this damage can result in reliability problems.

Electric Furnaces

An electric furnace consists of electrically heated coils, a fan to provide air circulation across the coils, and controls which include safety relays. Just like the gas-fired warm-air furnace, the electric furnace is susceptible to corrosion and damage, resulting in reliability problems or safety hazards. If there is any question whether flood water has reached an electric furnace, have the unit checked by a qualified heating professional.

Propane Heating

Use extreme caution when there is the potential for propane leaks and get propane equipment checked, repaired and/or replaced by a qualified heating professional as quickly as possible after a flood. In every case, all valves and controls that have been in contact with flood water must be replaced. Propane systems also require attention to their gas pressure regulator. This regulator contains a small vent hole in its body to sense outside pressure. For effective gas pressure regulation, this hole must always remain unobstructed. During a flood, debris can easily plug the hole, causing dangerous malfunction or corrosion. The regulator should be replaced, as water from floods can carry corrosive chemicals.

Radiant Ceiling Heat

In this type of heating system, electrically-heated cables are embedded in the plaster or drywall ceiling. The cables warm the ceiling, which in turn warms the room by radiant heat. If the ceiling becomes wet from a flood, the plasterboard will weaken and perhaps crack, and the ceiling will need replacement. Although the electrical cables themselves may appear to be undamaged due to their tough, waterproof coating, there may have been large mechanical stresses on the cable, and a qualified electrician should be consulted to determine whether the cable is reusable.

A qualified air conditioning or a heating/cooling professional can advise you whether your heating or cooling equipment can be salvaged. It depends upon the type of equipment, the depth of the floodwaters, and the duration of submersion. Many people try to salvage appliances such as dehumidifiers, refrigerators, and freezers that have been in flooded basements. This can be extremely dangerous. In some cases, ensuring appliances are safe can involve a destructive inspection that means repair may not be an option.

How do I know if someone is qualified?

  • Make sure they have a current electrical workers license as required by law.
  • If a provider is working with refrigerants in your system, ensure they hold an Approved Handler or Approved Filler license as required of nearly all users of refrigerants by legislation. Check this here
  • All heating and cooling systems have the potential for risk. Unlike most trades such as electricians, HVAC&R specialists are not required to be registered with a professional body. By working with companies that are members of the Climate Controls Companies Association (CCCANZ) and technicians who are members of the Institute of Refrigeration, Heating and Air Conditioning Engineers (IRHACE) you can be reassured you are working with people committed to professional development and training to ensure the highest levels of safety and delivery of services.
  • You can check if an individual is registered with the IRHACE here and that a company is a member of the Climate Controls Companies Association here.

With thanks to EcoChill, Refrigeration Specialties and the American Air Conditioning, Heating and Refrigeration Institute.

Recommendations for the Cleaning and Remediation of Flood-Contaminated HVAC Systems: A Guide for Building Owners and Managers


During flooding, systems for heating, ventilating, and air conditioning (HVAC) can become submerged in flood waters. As a result, these systems may contain substantial amounts of dirt and debris and may also become contaminated with various types of microorganisms such as bacteria and fungi. The following recommendations will help ensure HVAC systems contaminated with flood water are properly cleaned and remediated to provide healthy indoor environments.

Microorganisms may grow on all surfaces of HVAC system components that have been submerged in flood waters. In addition, moisture can collect in HVAC system components that were not submerged (such as air supply ducts above the water line) and can promote the growth of microorganisms. All components of the HVAC system that were contaminated with flood water or moisture should be thoroughly inspected, cleaned of dirt and debris, and disinfected by a qualified professional. The following recommendations will help ensure that HVAC systems contaminated with flood water are properly cleaned and remediated to provide healthy indoor environments.

Submerged HVAC equipment typically is damaged beyond what would be considered cost effective repair. Fully submerged equipment requires replacement of all open exposed electrical controls and motors. Likewise, gas piping, controls and burner systems require a combination of component part replacement and cleaning to assure proper, safe operation. In addition, submerged air handling or duct systems are subjected to the potential biological hazards caused by contaminated floodwater.

All things considered, complete equipment change-out, coupled with a thorough duct system replacement or cleaning, is likely required to restore safe, reliable HVAC system operation. The Climate Controls Companies Association New Zealand (CCCANZ) strongly recommends that all flood damaged HVAC systems remain off line until properly inspected by a skilled HVAC professional. It should also be noted that part replacement due to flood damage is not covered by the Standard, Limited Product Warranty, and product safety and reliability cannot be guaranteed after the product has been submerged in floodwater and/or mud. The degree of damage cannot be assessed without extensive evaluation of the product which can involve destructive inspection, making usability of the product impractical.

Steps Before Cleaning and Remediation

  • If the building is to remain partly occupied (for example, on upper floors not affected by flood waters), isolate the construction areas where HVAC systems will be cleaned and remediated by using temporary walls, plastic sheeting, or other vapor-retarding barriers. Maintain the construction areas under negative pressure (relative to adjacent non-construction areas) by using blowers equipped with HEPA filters (high-efficiency particulate air filters) to exhaust the area. To ensure complete isolation from the construction areas, it may be necessary to pressurize the adjacent non-construction areas and temporarily relocate the outdoor-air intake for the HVAC system serving the occupied areas.
  • Take precautions to protect the health of workers who are cleaning and remediating the HVAC system. Make sure that workers wear at least an approved respirator to protect against airborne microorganisms. Increased levels of respiratory protection (for example, powered, air-purifying respirators equipped with HEPA filters) may be appropriate depending on the level of visible contamination. In addition, when using chlorine bleach or other disinfectants in poorly ventilated environments, it may be necessary to use appropriate chemical cartridges in addition to the particulate filters to protect workers from breathing the chemical vapors.  A respiratory protection program can include a written standard operating procedure for the following: selecting and using respirators; the medical evaluation of workers to determine whether they are physically able to wear the respirator selected for use; training and instructions on respirator use; the cleaning, repair, and storage of respirators; the continued surveillance of work area conditions for worker exposure and stress; and a respirator fit-testing program. For tight-fitting respirators, fit-testing is necessary to help ensure that the respirator fits tightly, reducing the potential for leakage of outside air from around the edge of the mask. In addition, employers must provide workers with appropriate skin, eye, and hearing protection for the safe performance of their jobs.

HVAC Cleaning and Remediation

  • Remove all flood-contaminated insulation surrounding and within HVAC system components. Discard as per regulations.
  • Remove contaminated HVAC filter media and discard appropriately as per regulations.
  • After removing any insulation and filters, clean all flood-contaminated HVAC system component surfaces with a HEPA-filtered vacuum cleaner to remove dirt, debris, and microorganisms. Pay special attention to filter racks, drain pans, bends and horizontal sections of air ducts where debris can collect.
  • After removing any insulation or debris, disinfect all HVAC system component surfaces while the HVAC system is not operating. Use a solution of 1 cup of household chlorine bleach in a 4.5 liters of water. Do not mix bleach with other cleaning products that contain ammonia.
  • Conduct the cleaning and disinfection activities in a clean-to-dirty work progression. Consider the use of auxiliary fans to supply "clean" air to workers and carry aerosolized contaminant and disinfectant in the clean-to-dirty direction, away from the worker's breathing zones and towards the point of filtration and exhaust.
  • Follow the disinfection procedure with a clean water rinse. Depending on the amount of debris present, it may be necessary to mechanically clean the HVAC system component surfaces with a steam or a high-pressure washer before using the disinfectant. Gasoline powered pressure washers should be used outside or with adequate exhaust ventilation to prevent carbon monoxide hazards.

Note: Remove and discard HVAC system components that are contaminated with flood water, and cannot be effectively cleaned and disinfected. Replace them with new components.

  • After cleaning and disinfecting or replacing the HVAC system components, replace the insulation – preferably with an external (i.e. not in the air stream) smooth-surfaced insulation to help prevent debris and microorganisms from collecting in the future.
  • Make sure that the HVAC system fan has been removed and serviced (cleaned, disinfected, dried thoroughly, and tested) by a qualified professional before it is placed back into the air-handling unit.
  • During the cleaning and remediation process, consider upgrading the HVAC system filtration to the highest efficiency filters practical, given the static pressure constraints of the HVAC system fan. This step has been shown to be one of the most cost-effective ways to improve the long-term quality of the indoor environment, since it reduces the amount of airborne dusts and microorganisms.

Resuming HVAC Operations

  • After cleaning and disinfecting or replacing HVAC system, have a qualified professional thoroughly evaluate its performance and correct it as necessary before the building is occupied again. The HVAC system performance should conform to the recommendations contained in ASHRAE Standard 62.1-2007, Ventilation for Acceptable Indoor Air Quality.
  • Before the building is occupied again, operate the HVAC system continuously in a normal manner at a comfortable temperature for 48 to 72 hours. During this period, it may be beneficial to open the HVAC outdoor air dampers to the maximum setting that still allows you to provide the desired indoor air temperatures. If flood-related odors persist after this "flush out" period, reassess by looking for flood-contaminated areas that were not identified earlier and continue the flush-out process until odors are no longer apparent. Replace the HVAC filters used during the flush-out prior to building occupancy.
  • After a building is occupied again, make frequent (for example, weekly) checks of the HVAC system to ensure that it is operating properly. During these checks, inspect the HVAC system filters and replace them when necessary. Gradually reduce the frequency of the HVAC system checks to monthly or quarterly inspections, depending on the routine operation and maintenance specifications for the HVAC system.
  • If no routine operation and maintenance program is in place for the HVAC system, develop and institute such a program. At a minimum, include the following routine procedures: inspection and maintenance of HVAC components, calibration of HVAC system controls, and testing and balancing of the HVAC system.
  • After the building is occupied again, maintain the interior temperature and relative humidity to conform to the ranges recommended in ASHRAE Standard 55- 2004, Thermal Environmental Conditions for Human Occupancy.

With thanks to EcoChill, Refrigeration Specialties and the American Air Conditioning, Heating and Refrigeration Institute.

Additional Resources