WELLTEC DHN20, Manual

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7. Repair of sealed components
a. Before removing sealed covers, etc. during repair, turn off all power sources for the equipment that will be serviced. If the
equipment must be powered during service, a permanently functioning refrigerant leak detector should be placed in a critical
place to alert you to potentially hazardous situations.
b. Particular attention should be paid to the following aspects to ensure that when working with electrical components, the guards
are not damaged which could reduce the level of protection.
c. This includes cable damage, excessive connections, non-compliant connectors, gasket damage, incorrectly positioned glands,
etc. Make sure that the device is positioned securely.
d. Check if the seals or sealing materials have not been damaged to the extent that would limit their function, i.e. preventing the
entry of flammable substances into the housing. Spare parts must comply with the manufacturer's specifications.
e. NOTE! The use of silicone sealants may limit the effectiveness of some leak detection devices. Intrinsically safe components do
not have to be insulated before starting work.
8. Repair of 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.
9. Wires
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.
10. Detection of flammable refrigerants
Under no circumstances should potential ignition sources be used to search for or detect refrigerant leaks. Do not use gas burners
(or other detectors that use exposed flame).
11. Leak detection methods
The following leak detection methods are considered to be suitable for systems containing flammable refrigerants.
For flammable refrigerants use electronic leak detectors. Please note that they may not have sufficient sensitivity or require
calibration. (The equipment should be calibrated where the refrigerant is not present.) Make sure that the detector is not a potential
ignition source and that it is suitable for the type of coolant used. The leak detection device should be set to a fraction of the lower
refrigerant explosion limit and calibrated for the specific refrigerant, and the correct gas concentration (maximum 25%) must be
confirmed.