Implement a regular check of refrigerant levels
Process area: Refrigeration
Payback: <3 months payback
Avg. save: €1,720
There is an F gas requirement to check and ensure logging. On this basis, the viability of full-time monitoring equipment is sensible. Lack of maintenance or small plant leaks can lead to a slow reduction in refrigerant levels. This is a more relevant to a unit system (direct expansion).
- Effects: inefficient cooling, oil logged evaporators.
- Fix: Check and log the levels and pressures. If you find any loss of refrigerant occurring, fix leaks and replenish.
Tips & advice
Do a visual check through the side glass of the levels; this is zero cost - if it's flashing as the liquid goes through, that indicates it's not fully charged.
With your contractor, or in-house, your maintenance procedure should at least cover:
- Identifying and fixing any leaks.
- Checking seals are still intact (pressure reduction can damage seals).
- Replenishing refrigerant, logging how much and when you did it - include gas type.
For an accurate charge:
- Charge by weight if you know what this should be. The OEM system designer may have worked this out on commission of the plant and provided it. This needs a qualification - 2078 to top up F gas, 2079 Ammonia version - so bring in help if your team doesn't have it.
- Different types of systems will have different ways of checking: - Flashing of the sight glass. - You might see oil outside the system (lubrication for the compressors - tends to leak through so residue can be a sign). Clean plant its easy to spot - well-maintained plant room makes it easy to spot. - the level within the high-pressure receiver (HPR) may change from typical operating parameters.
- Charge to a full sight glass, but be aware that bubbles in the sight glass can also mean that there is a blockage in the liquid line, that the condenser is significantly undersized or the system is over condensing due to faulty or incorrectly set head pressure controls. If the sight glass is on the condensing unit or pack and there is a long or heated liquid line, a clear sight glass will not necessarily indicate clear liquid at the expansion valve.
Also consider these additional tips:
- If a leak has been significant, you may have to report it to your environment regulator.
- A good indication of low refrigerant level is to observe the sight glass in the refrigerant liquid line to the evaporator. If a constant stream of bubbles is visible, refrigerant levels should be checked.
- If you don't have fixed leak detection, at least plot a graph of every gas top-up you do. You'll be able to spot if there are any sudden increases due to leaks.
- Establish an incentive-based employee performance programme to help contain leakage.
- Where you are modifying systems, minimize mechanical joints – there will be less risk for future leakage. Leaks are common with flared fittings, which you should try to minimize in favor of brazed or bended pipes (sealed fittings).
- Use UV Dye in the system's oil for cheap leak detection.
- Leaks cost money. Fixed systems can pick up gases, but oil leaks can damage equipment. You can buy a UV Dye compatible with the oil, and a cheap UV detector to get a low-cost detection system you can deliver in-house, potential saving on maintenance and contractors.
- Check UV oil is compatible with your system. Introduce dye. Use detector weekly to find & fix any leaks.