Air Conditioner Repair
Air conditioning systems will always require repairs over time. Small air conditioner repair issues can be dealt with within a couple of hours. Major breakdowns of mechanical parts, like a compressor, will take days to repair and have the system back up and running. The de-commissioning process of shutting down a commercial air conditioning system can take days alone. Following the repair, the ac pre-commissioning works then take several more days to have the system back in operation. The refrigerant gas needing to be removed from a system is the most time-consuming task involved. Furthermore, high volumes of gas need to be removed and pumped into recovery gas cylinders. The gas can be reused only if the compressor hasn’t failed or there has been no refrigerant gas leak.
Home Air Conditioning Systems
Residential air conditioning systems carrying small amounts of refrigerant can be put on the pump down to recover the gas in the system for an air conditioner repair. The process can only be used if the air conditioner repair does not involve removing mechanical parts in the condenser. Pumping down the gas is a very safe simple task. It can be performed with a set of gauges and an Allen key.
Pump Down
The process described as ‘pumping down’ refers to using the ac systems compressor to pump all the gas into the condenser. On a bespoke wine cellar cooling system, this process is used as part of the system operation feature. In the defrost mode, heaters activate to defrost the evaporator, which is filled with gas could cause high-pressure faults. The use of pipework solenoids to control the gas supply to the evaporators is therefore essential. The solenoid will be linked to the control system which will allow or stop the flow of refrigerant gas depending on the mode of operation. Restricting the liquid line flow of refrigerant, while the compressor is running, will cause all the gas to collect in the condenser. The gas can be pumped down on an air conditioning system by manually closing the liquid service valve at the condenser. Attach a set of gauges and close the low side service valve while watching the pressure fall. When the pressure is at zero, all the gas has been collected at the condenser. This allows the safe removal of the interconnecting pipework.
What if you cannot pump down
The pump-down procedure can be performed if the condenser has the capacity to reclaim the gas. Also, this is ONLY if the compressor runs. On a new air conditioning installation or refrigerant system install, additional gas will need to be added at times. The amount of refrigerant required depends on the length of the interconnecting pipe runs. The amount of refrigerant can be double that of the original pre-charged amount meaning a pump down is not possible. This is because the condenser and liquid receiver do not have the internal capacity to hold this charge. Therefore, the gas will need to reclaimed by a recovery machine and gas cylinder used to hold the charge. The recovery machine adopts the role of the compressor is pumping the refrigerant out of the system. As mentioned previously, this gas can only be reused if the compressor hasn’t failed or a gas leak occurred.
Why can gas not be reused?
In the event of an air conditioning system failure, the burnt-out mechanics of the compressor mixing with air vapour moisture, refrigerant oil and gas, become acidic. The acid will contaminate the entire system through the spread of the oil in the gas. Therefore, the gas is a contaminate that should not be reintroduced back into the system after the compressor change. In addition, it may be necessary to install “burnt out” driers on the refrigerant lines, to catch acidic mixture. Using burnout driers is often a discretionary measure seen used on commercial chillers and other commercial climate control systems. The burnout driers will be changed after some hours of operational testing to remove the collected acid mixture and gas changed out also. The filter drier cores of commercial chillers will also be changed out on a compressor change.
Avoid an air conditioner repair with HVAC maintenance
Professional and experienced Heating, Ventilation and Air Conditioning Contractors should be called for the de-commissioning of large HVAC systems. The video below demonstrates a simple ac pump down procedure on a ductless mini-split home ac system. Fgas regulations for the handling of refrigerant gases require persons to be duly qualified in the UK. If you are not an experienced and qualified air conditioning installation contractor in London then contact us today for assistance with your gas reclaim project.
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