A-Gas Managing Director John Ormerod with ten top tips on how to maintain best practice when replacing R404A with a lower GWP refrigerant.
1. Why is it important to make the switch from R404A to a lower GWP refrigerant?
This is the time to focus on replacements for R404A, one of the most widely used refrigerants in the industry. The F-Gas quota system is making an impact as the push towards reducing the amount of high GWP refrigerant in use gathers pace.
R404A, with a GWP of just under 4000, will be one of the hardest hit by the changes and everyone agrees that if business continues as usual, by 2018 there won’t be enough of this refrigerant to go around to meet the needs of the industry.
2. How do you decide on which refrigerant to choose for the retrofit?
The industry should banish the word drop-in because there really is no such thing. With the introduction of any replacement refrigerant an adjustment will have to be made to the system to get the best out of it; it is not a case of simply dropping it in.
3. Which retrofit refrigerants spring to mind?
There are several suitable retrofit refrigerants on the market – R407F is a medium GWP option but Opteon XP40 (R449A) and Solstice N40 (R448A) offer a lower GWP alternative. They are currently the lowest GWP replacements on the market (around 1400) and are closely matched to R404A in terms of refrigeration capacity.
4. What is the easy way to record the amount of refrigerant recovered?
5. How should you dispose of the old oil from the compressor?
A-Gas offers an oil disposal service through its wholesale partners to take care of recovered oil. Each container has a venting cap to ensure any refrigerant absorbed in the oil does not cause the waste container to expand. This is a safe and environmentally friendly way of dealing with what has been in the past a tricky problem.
6. How does the choice of refrigerant affect the charge size?
Follow the refrigerant manufacturer’s recommendation regarding initial charge size before making adjustments to the system. Use dew point pressure as a reference in determining the appropriate temperature for a superheat setting. To determine the saturated temperature for a sub-cooling calculation use bubble point pressure.
7. Why is leak testing so important?
The route to success is to follow best practice, so relying on pressure or vacuum decay – or using bubble spray – won’t be enough. Technologies like Trace-A-Gas® from A-Gas can provide a high tech and economical solution. Using a suitable detector, this method is 100 times more sensitive than bubble spray. Leaks can be detected in the smallest quantities and very quickly.
8. How should you monitor the system performance?
9. Why is labelling so important?
As the regulations march on it is likely that we are going to have many different types of refrigerants used, so labelling has never been more relevant. It is also important for engineers to know exactly what’s in a system. Generic F-Gas refrigerant tape is now available to allow systems to be labelled accordingly with all of the required information.