How to troubleshoot offshore reefers?
There are a variety of concerns that can arise with any refrigeration system such as :
- inappropriate amperage
- oil problems
- airflow issues
This article explains how to spot and deal with some of the most prevalent problems.
The amperage drawn by the compressor may be affected by problems in the refrigeration system.
When incondensable items are present for example, the compressor has to work harder, resulting in a high amperage measurement.
High amperage draw can also be caused by loose wire connections and overheating.
An inefficient compressor, on the other hand, consumes less power.
To undertake electrical repairs for any amperage draw issues, the building engineer should engage an expert electrical contractor.
The oil level is fine, according to most manufacturers, as long as oil can be seen in the sight glass.
Some, on the other hand, recommend that oil levels be between one-third and two-thirds of the way up the sight glass.
One point that all manufacturers agree on is that the oil level should not be higher than the sight glass, which may give the impression that it is empty.
Always follow the manufacturer’s recommended oil level and kind of oil.
Though constraints can develop anywhere in the system, they are more likely to occur in metering devices or filter driers with smaller apertures.
A suction or liquid line might get kinked or crushed at any time.
The limitation may be significant enough to cause frost, or it may be minor and difficult to perceive at other times.
Gauges and temperature probes will offer the data needed to evaluate whether or not there is a limitation and how severe it is.
The limitation is almost always encountered on the liquid line.
Some of the warning signals to check for are :
- High superheat
- low suction pressure
- low compressor amperage draw
Variable frequency drives and various speed motors have grown commonplace in recent years.
The airflow through a DX coil or chilled water coil is continually changing because of variable frequency drives, adjustable speed drives, variable air volume (VAV) boxes, and intake guiding vanes.
The refrigeration pressures alter as a result of this.
The following are a few items that have an impact on the airside of a system:
- The filter is clogged.
- The evaporator coil is filthy.
- The fan speed is incorrect.
- A belt that is loose or damaged, or a sheave that has to be adjusted
- Diffuser with a closed supply.
- Return diffuser is closed.
- Ducting was put incorrectly.
Solenoid Valve with a Leaking Liquid Line
If the liquid line solenoid valve has a significant leak, the compressor may not be able to lower the suction pressure enough to stop the pump down cycle.
This will force the compressor to run at its lowest loading stage indefinitely.
A temperature decrease across the valve body and the emergence of flash gas in the liquid line sight glass indicates a leaky valve.
In conclusion, we have discussed a variety of concerns that can arise with any refrigeration system and how to spot and deal with some of the most prevalent problems.
We also touched on some of the warning signals to check for as well as a few items that have an impact on the airside of a system.
A graduate (Business) from KDU, Jason Tan, is the current Business Director (Sales) for MGS Icestorm and has been associated with the company for the past 10 years.
With over 13 years in the shipping industry, he has had a significant contribution to Malaysia’s oil and gas industry in the engine and boat supply sector.
His expertise includes managing offshore catering business, offshore reefer containers, AI technology, offshore gas tanks, A60 pressurized cabins, etc. His contributions have helped establish MGS, in partnership (joint venture) with Thermo King and Honeywell to produce state of art Offshore Reefer Container products.