7.3 – COOLANT GAS LEAKS 7.2.2 - REMEDY The only permanent remedy is to replace the dehydrator filter with a new one (see 7.8).In the meantime, proceed as follows: With the system switched off, heat the thermostatic valve with a cloth soaked in very hot water until, melting the ice inside, the cooling circuit is restored and you can hear a hiss coming from the valve. At the same time you can temporarily raise the setting on the thermostat slightly. Only do this if strictly necessary as, after a certain amount of time, the phenomenon will repeat itself. Replacing the filter resolves the problem as it brings the coolant gas to its original, pure state. Any other operation is not recommended and will usually damage the system. The FRIGOBOAT TWIN 2000 series cooler is supplied with 550 g of R134A coolant. This is usually enough forthe cooler to function for a number of years. An empty system will show the following symptoms:A) The cooler is not producing much cold and requires a much longer time than it should do to freeze theholding plate.B) The expansion valve on the plate is whistling loudly. C) The liquid indicator installed on the pipes (B) used to transport liquid shows gas bubbles in the coolant (theliquid indicator may also be totally empty due to lack of coolant).The manifestations in points B and C must occur simultaneously. If only one occurs you cannot be sure that the system is empty and you will need to check Chapter 6 again or check the system with the manometers. If a system is empty, you need to find out why and eliminate the causes before refilling. This is difficult unless there is a major leak, because coolant gas is colourless and odourless. Therefore we recommend that you use a special leak detector for boats or soapy solution. Moreover, the presence of oil on a component is a good clue as to the location of the leak point: in fact, the coolant takes lubricant for boat from the compressor and leaves an oily trace behind when it evaporates. A leak of coolant on the suction side usually does not entail an oil loss; suction means the part of the circuit between the plate and the compressor.Make a systematic check as follows:A) Examine the state of the plastic tubes, particularly those close to the engine and the battery, or cutting metalparts. The continuous vibration to which the tubes are subjected may have caused abrasions (if in contact with other parts) or harmful electrical discharges (if close to the battery).B) Carefully examine all quick couplings, searching for oiliness on the exterior. If an ‘O’ ring is pinched duringassembly, there will definitely be a leak.If these external checks are negative, you will have to find the leak with a leak detector. To use a leak detector, the system must not be entirely empty. If it is empty at this point, partially refill it (see Chapter 7.9). If the leak if discovered on the suction side of the system (the part between the thermostatic valve and the compressor) and the compressor has operated in these conditions, air will probably have been sucked into the refrigerator for boats circuit. Therefore, once the leak has been found and repaired, you will have to eliminate the air from the system before refilling. If you still cannot find the leak with the leak detector and the system is still leaking gas, you can open the system by unscrewing the couplings and relative plugs in order to isolate it into two parts. The part that is losing gas is the one with the leak. WARNING: 7.4 - SERVICING THE REFRIGERATOR CIRCUIT If you cannot repair the leak immediately (when you find it), we recommend that you:A) Do not run the system. B) If the leak is large enough to lose all pressure (if a tube has broken etc), isolate the faulty part from the rest of the system by unscrewing the quick couplings 4.5 rotations (not completely) immediately either side of the leak point. Before opening any quick coupling, you must make sure that the majority of the coolant is contained as liquid inthe reserve, so that the rest of the system is free of coolant. This limits the risk of large leaks of coolant and oil.Proceed as follows:A) Unscrew the nut of the female coupling (position 2) 4.5 rotations at the base of the reserve WITHOUTREMOVING IT COMPLETELY .B) Operate the system until the filter becomes very cold and the suction manometer shows 0 (this may take 1 to2 minutes).C) The compressor stops by itself, triggered by the low pressure switch (LP). 15