21
longer serve the purpose of preventing the ingress of flammable atmospheres.
Replacement parts shall be in accordance with the manufacturer’s specifications.
NOTE
: The use of silicon sealant may inhibit the effectiveness of some types of
leak detection equipment. Intrinsically safe components do not have to be isolated
prior to working on them.
3. Repair to intrinsically safe components
Do not apply any permanent inductive or capacitance loads to the circuit without
ensuring that this will not exceed the permissible voltage and current permitted
for the equipment in use.
Intrinsically safe components are the only types that can be worked on while live
in the presence of a flammable atmosphere. The test apparatus shall be at the
correct rating. Replace components only with parts specified by the manufacturer.
Other parts may result in the ignition of refrigerant in the atmosphere from a leak.
4. Cabling
Check that cabling will not be subject to wear, corrosion, excessive pressure,
vibration, sharp edges or any other adverse environmental effects. The check shall
also take into account the effects of aging or continual vibration from sources
such as compressors or fans.
5. Detection of flammable refrigerants
Under no circumstances shall potential sources of ignition be used in the searching
for or detection of refrigerant leaks. A halide torch (or any other detector using a
naked flame) shall not be used.
6. Leak detection methods
The following leak detection methods are deemed acceptable for systems
containing flammable refrigerants.
Electronic leak detectors shall be used to detect flammable refrigerants, but the
sensitivity may not be adequate, or may need re-calibration. (Detection equipment
shall be calibrated in a refrigerant-free area.) Ensure that the detector is not a
potential source of ignition and is suitable for the refrigerant used. Leak detection
equipment shall be set at a percentage of the LFL of the refrigerant and shall be
calibrated to the refrigerant employed and the appropriate percentage of gas (25
% maximum) is confirmed.
Leak detection fluids are suitable for use with most refrigerants but the use of
detergents containing chlorine shall be avoided as the chlorine may react with the
refrigerant and corrode the copper pipe-work.
If a leak is suspected, all naked flames shall be removed/ extinguished.
If a leakage of refrigerant is found which requires brazing, all of the refrigerant
shall be recovered from the system, or isolated (by means of shut off valves) in a
part of the system remote from the leak. Oxygen free nitrogen (OFN) shall then be
purged through the system both before and during the brazing process.
15429_Dimplex DPRC40U Manual.indd 21
15429_Dimplex DPRC40U Manual.indd 21
9/09/20 6:40 PM
9/09/20 6:40 PM
