Taking a warm shower or bath is one of the best ways to relax after a long day, and a water heater working efficiently and safely would be a big help.
The February issue of CHOICE magazine (No. 436) reported on the latest safety tests on electric water heaters. 3 samples outpaced the others by passing most of the test items.
The test covered 10 samples including 3 of the unvented storage type, 3 of the shower storage type and 4 of the instantaneous type, with retail prices ranging from HK$1,190 to HK$3,080.
Unvented and instantaneous type water heater can be connected to multiple water outlets located in bath tub, wash basin, kitchen basin and so on. On the other hand, the shower storage type can only be fitted with one unblocked showerhead without any on/off control valve.
The test was conducted in accordance with international standards, namely IEC60335-2-21 / IEC60335-2-35. The results indicated that all the samples passed most of the basic test items.
It is noted that 1 unvented storage and 2 instantaneous samples passed most test items, while they required improvement in labelling and instructions.
The following problems were found respectively in the remaining 7 samples, which have to be fixed:
- 1 of the samples did not meet the requirement for protection against electric shock. During the safety tests, the test finger touched the sample's internal cable and connectors insulation material when it reached through the openings at the inlet and outlet pipes.
- 3 of the samples did not have drain holes on their covers, or the size of drain holes failed to meet the standards.
- 5 of the samples were not properly earthed.
- Inadequate insulation distance between the primary and secondary windings in the internal transformer of 1 of the samples was found. Moreover, part of the material of its plastic enclosure also failed to pass the resistance to heat and fire test.
- The labeling and instructions of all these samples were found to be inadequate. It is mainly because they failed to meet certain requirements regarding warning or instruction.
Consumers are advised to observe the following to ensure safety when using electric water heaters:
- Installation or modification of electric water heater must be carried out by registered electrical contractors, registered electrical workers and licensed plumbers.
- Electric water heater should be connected to stand-alone power circuit with its own on/off switch.
- Never install any on/off control valve on the outlet pipe of a shower storage type water heater, or connect the outlet pipe to washing basin or bath tubs. It is dangerous to do so. When the tap is turned off, pressure may not be released properly. Potential risks of explosion will be created as a result of excessive pressure inside the water tank.
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- 2013.02.18