As I write this I was reminded we have precisely 400 days left of having R22 available as a serviceable refrigerant.
Whereas after 31st December next year R22 can still be used within operating systems, any reason for it leaving a system will render that system non-serviceable.
The available solutions for R22 replacement are not and never have been panacea solutions. Anyone who envisages a quick profit by a swift gas change to one of the many replacement blends is in for an expensive shock.
Expect system leaks, broken fans, worn out system control valves, system leaks, controls faults, compressor faults, dirty heat exchangers, system leaks…
Did I mention system leaks?
More importantly expect to meet customers who sometimes fail to understand what the common quotation terms ‘…plus any other faults found …’ and ‘…non warranted works…’ actually mean in practice.
R22 conversion is never the same for two systems, even two systems on identical chillers on the same site. All R22 equipment will be at least 12 - 14 years old and the available solutions are not a five minute fix. Waiting for a leak then trying to make a system already effectively broken work again properly is a recipe for major overspends.
Having been at the sharp end of Gas Retrofit for some 16 years I would offer the following tips…
1: Do not offer any warranty, especially for any failures (e.g. compressors) or leaks.
2: Highlight in bold type the high probability of extra works arising.
3: Expect compressor failures within 6 months, and do not be surprised if some are found on the brink of failure when undertaking the works.
4: Label the system with the qty removed and qty re-charged with the new blend used.
5: Expect the re-charge volume to be different – sometimes 30% less, rarely more.
6: Be very clear on leakage liabilities – a leak test is like a car’s MOT, only good at the time of the test.
7: When these systems re-leak the gas loss and replacement works will be as expensive as the original retrofit works.
8: Age related faults do not always show up when most convenient.
9: Do not over pressurise the low side of older systems.
10: Be wary of sometimes correct advice to adjust the system TEVv. This means loosening the valve settings to compensate for higher liquid flow rates on certain replacement refrigerants. Loosening the TEVv means reducing the Superheat control, and at low loads this can be dangerous for the compressor. This advice works for small systems, but for larger systems installing a larger TEVv or TEVv orifice is the proper solution.
©Trevor Dann - July 2013
Technical & Sales Director at ThermaCom Ltd