GB/T 4706.12-2024 Safety of household and similar electrical appliances - Part 12: Particular requirements for storage water heaters
1 Scope
This clause of GB/T 4706.1-2024 is replaced by the following.
This standard deals with the safety of electric storage water heaters for household and similar purposes and intended for heating water below boiling temperature, their rated voltage being not more than 250 V for single-phase appliances and 480 V for other appliances.
Appliances not intended for normal household use but which nevertheless may be a source of danger to the public, such as appliances intended to be used by laymen in shops, in light industry and on farms, are within the scope of this standard.
This document is also applicable to Class I water heaters that explicitly provide emergency protection measures when the earthing system is abnormal. Such a unit shall comply with the requirements in Annex AA.
This standard is also applicable to immersion heater units intended to be retrofitted in a heat exchange closed water heater having provision for retrofitting. Such a unit shall comply with the requirements in Annex BB.
As far as is practicable, this standard deals with the common hazards presented by appliances that are encountered by all persons in and around the home. However, in general, it does not take into account
- persons (including children) whose
physical, sensory or mental capabilities, or
lack of experience and knowledge
prevents them from using the appliance safely without supervision or instruction;
- children playing with the appliance.
Note 101: Attention is drawn to the fact that
- for appliances intended to be used in vehicles or on board ships or aircraft, additional requirements may be necessary;
- in many countries additional requirements are specified by the national health authorities,
- in many countries regulations exist for the installation of equipment connected to the water mains.
Note 102: This standard does not apply to
- appliances for boiling water (GB/T 4706.19);
- instantaneous water heaters (GB/T 4706.11);
- commercial dispensing appliances and vending machines (GB/T 4706.72);
- appliances intended exclusively for industrial purposes;
- appliances intended to be used in locations where special conditions prevail, such as the presence of a corrosive or explosive atmosphere (dust, vapour or gas).
2 Normative references
This clause of GB/T 4706.1-2024 is applicable except as follows:
Addition:
GB/T 16839.1-2018 Thermocouples - GB/T 4706.1-2024 : EMF specifications and tolerances (IEC 60584-1 : 2013, IDT)
GB/T 20044-2012 Electrical accessories - Portable residual current devices without integral overcurrent protection for household and similar use (PRCD)
3 Terms and definitions
This clause of GB/T 4706.1-2024 is applicable except as follows.
3.1.9 Replacement:
normal operation
operation of the appliance after installation in accordance with the instructions and filled with cold water
3.101
storage water heater
stationary appliance for heating and storing water in a container and incorporating devices to control the water temperature
3.102
closed water heater
unvented storage water heater intended to operate at the pressure of the water system, the flow of water being controlled by one or more valves in the outlet system
Note 1: A closed water heater is shown in Figure 101 a)
Note 2: The operating pressure may be the output pressure of a reducing or boosting device.
3.103
cistern-fed water heater
storage water heater that is vented to atmosphere and intended to be supplied by water under gravity from a separate cistern, the flow of water being controlled by one or more valves in the outlet system
Note 1: A cistern-fed water heater is shown in Figure 101 d).
Note 2: The water heater may be installed so that the expanded water returns to the cistern.
Note 3: In a cistern-fed water heater, the pressure in the container results from the column of water in the cistern.
3.104
cistern-type water heater
storage water heater having a container supplied by water under gravity from a cistern incorporated in the appliance.
Note 1: The expanded water can return to the cistern, the flow of water being controlled by one or more valves in the outlet system.
Note 2: A cistern-type water heater is shown in Figure 101 c).
Note 3: In a cistern-type water heater, the surface of the water is always at atmospheric pressure.
3.105
open-outlet water heater
storage water heater in which the flow of water is only controlled by a valve in the inlet pipe and in which the expanded or displaced water flows through the outlet
Note 1: An open-outlet water heater is shown in Figure 101 b).
Note 2: In an open-outlet water heater, the static pressure at the outlet is always at atmospheric pressure.
3.106
low-pressure water heater
storage water heater that is vented to atmosphere and intended to be connected to the water mains through a pressure reducing valve, the flow of water being controlled by one or more valves in the outlet system
Note: A low-pressure water heater is shown in Figure 101 e).
3.107
rated pressure
water pressure assigned to the appliance by the manufacturer
3.108
heat exchange water heater
storage water heater in which heated water is fed into a heat exchanger, which is itself immersed in a container with the water to be heated.
Note 1: The heated water fed into the heat exchanger is heated from a primary heat source such as a solar panel or heat pump.
Note 2: A heat exchange water heater is shown in Figure 101 f).
Note 3: Example of heat exchanger: coil.
4 General requirement
This clause of GB/T 4706.1-2024 is applicable.
5 General conditions for the tests
This clause of GB/T 4706.1-2024 is applicable except as follows.
5.2 Addition:
Note 101: Additional appliances can be required if damage occurs during the tests of 19.2 or 19.3.
5.3 Addition
When the tests are carried out on a single appliance, the tests of 22.47, 22.102, 22.103, and 24.102 are carried out before the tests of Clause 19.
6 Classification
This clause of GB/T 4706.1-2024 is applicable except as follows.
6.1 Modification:
Water heaters shall be class I, class II or class III.
6.2 Addition:
Water heaters for installation outdoors shall be at least IPX4. Other water heaters shall be at least IPX1.
7 Marking and instructions
This clause of GB/T 4706.1-2024 is applicable except as follows.
7.1 Addition:
Appliances, other than cistern-type water heaters, shall be marked with the rated pressure in pascals (Pa).
Appliances shall be marked with the rated capacity in litres (L).
Closed water heaters shall be marked with a statement that a pressure-relief device is to be fitted in the installation, unless it is incorporated in the appliance.
Closed water heaters having a rated pressure less than 0.6 MPa and low-pressure water heaters shall be marked with a statement that a pressure reducing valve is to be fitted in the installation.
Open-outlet water heaters shall be marked, close to the outlet connection or on a tag attached to the appliance, with the substance of the following:
WARNING: This outlet acts as a vent and must only be connected to a fitting recommended by the manufacturer. It must not be connected to a tap.
7.12 Addition:
The instructions for closed water heaters shall state the substance of the following:
- the water may drip from the discharge pipe of the pressure-relief device and that this pipe must be left open to the atmosphere;
- the pressure-relief device is to be operated regularly to remove lime deposits and to verify that it is not blocked;
- how the water heater can be drained.
7.12.1 Addition:
The installation instructions shall state the substance of the following:
- the type or characteristics of the pressure-relief device and how to connect it, unless it is incorporated in the appliance;
- a discharge pipe connected to the pressure-relief device is to be installed in a continuously downward direction and in a frost-free environment;
- the type or characteristics of a pressure reducing valve and the installation details (for appliances having a rated pressure less than 0.6 MPa).
The instructions for closed water heaters incorporating a heat exchanger shall give details on the installation of control devices and the temperature settings that are necessary to prevent operation of the thermal cut-out caused by the heat from the exchanger.
The instructions for cistern-fed water heaters and low-pressure water heaters shall contain the substance of the following:
WARNING: Do not connect any pressure-relief device to the vent pipe of this water heater.
7.101 The water inlet and the water outlet shall be identified. This identification shall not be on detachable parts. If colours are used, blue shall be used for the inlet and red for the outlet. An alternative means of identification may be by means of arrows showing the direction of the water flow.
Compliance is checked by inspection.
7.102 For Class I water heaters that intend to provide emergency protection measures when the grounding system is abnormal, there should be corresponding explicit contents in the operating instructions.
7.103 For appliances with waterproof rating lower than IPX4, the installation instructions shall state that this appliance is forbidden to be installed outdoors or in shower places.
8 Protection against access to live parts
This clause of GB/T 4706.1-2024 is applicable.
9 Starting of motor-operated appliances
This clause of GB/T 4706.1-2024 is not applicable.
10 Power input and current
This clause of GB/T 4706.1-2024 is applicable.
11 Heating
This clause of GB/T 4706.1-2024 is applicable except as follows.
11.3 Addition:
Where the external accessible surfaces are suitably flat and access permits, then the test probe of Figure 103 maybe used to measure the temperature rises of external accessible surfaces specified in Table 101. The probe is applied with a force of 4 N±1 N to the surface in such a way that the best possible contact between the probe and the surface is ensured. The measurement is performed after a contact period of 30 s.
The probe may be held in place using a laboratory stand clamp or similar device. Any measuring instrument giving the same results as the probe maybe used.
11.7 Replacement:
The appliance is operated until steady conditions are established or until the thermostat interrupts the current for the first time after 16 h, whichever is shorter.
11.8 Modification:
During the test, the temperature rises are monitored continuously and shall not exceed the values shown in Table 3 and Table 101.
