Do-it-yourself electric storage water heater installation: connection diagrams

Recommendation points

• Features of installing a wall-mounted water heater
• Wiring diagrams of a wall-mounted storage water heater
• Diagrams for connecting the water heater to the mains
• Cable
• Power socket
• Protection devices – RCDs and circuit breakers
• Connection diagrams
• Features of connecting a floor water heater

Nothing will prevent you from installing an electric storage-type water heater with your own hands if you are “friends” with tools. Let’s look at the basic connection diagrams that will help you understand the installation details and connect the boiler to the water supply and power supply.

An electric storage water heater is a heat-insulated storage tank with heating elements (heating elements) inside, cold water inlet and hot water outlet fittings and automatic temperature control. They can be wall-mounted and floor-mounted, horizontal and vertical. Each type of installation has its own characteristics.

Haier wall-mounted storage water heater device: 1 – hot water outlet; 2 – cold water supply; 3 – storage tank; 4 – thermocouple; 5 – heating element; 6 – magnesium anode (corrosion protection); 7 – brackets

Features of installing a wall-mounted water heater

First of all, when installing a wall-mounted water heater, you must make sure that the wall can withstand the additional load. Equipment manufacturers recommend taking four times the weight of the boiler filled with water when calculating. But since few people can correctly calculate the loads of building structures, the following rules should be followed:

1. The load-bearing wall can support the weight of almost any domestic water heater.
2. When installing the boiler on walls, especially in “Khrushchevs”, or walls made of hollow bricks, small tanks can still be hung simply on the anchors. It is better to install more or less spacious drives on a wall, reinforced with racks, or fasten on through bolts fixed for reliability with a tie.

Fastening the storage tank to the wall

Wiring diagrams of a wall-mounted storage water heater

The fittings for supplying cold and removing hot water are located at the bottom of the wall-mounted boiler and are marked in blue and red, respectively. The connection to the backbone can be done in two ways:

• no security group;
• with security team.

Circuits without a safety group can be used when connecting a water heater designed for a pressure exceeding the head in the main cold water supply, if this head is stable. In case of unstable, strong pressure in the line, preference should be given to connection through a safety group.

In any case, the connection and installation of the water supply system begins with inserting tees into the cold and hot water pipelines after the taps installed at the inlet of the water pipes to the apartment.

Attention! If the pipes in the house have not changed for a long time, you need to check their condition before work. Rusty steel pipes may need to be replaced with new ones.

From the tees, taps are made to connect the water heater. When the boiler is operating, the hot water tap must be completely closed. Cold water flows freely for heating, faucets, and the toilet tank.

On the boiler, a non-return safety valve is screwed onto the cold water supply connection. It protects against thermal expansion of water in the storage tank, periodically bleeding off excess water. A drainage pipe is mounted from the valve drain hole, which must be directed downward and lower into the tank or sewer freely, without kinks, which could prevent the drainage of excess water in the tank.

Non-return safety valve

No shut-off valves can be installed between the valve and the water heater. But the tee, on the branch of which a tap is installed to empty the tank, can be installed, and even recommended by manufacturers. The pipe or hose from it must be brought into the sewer, or with a tee connected to the cold water supply pipe up to the safety valve.

At the outlet of the hot water boiler and at the inlet of cold water, immediately after the non-return valve, it is necessary to install taps that shut off this line during the period when the water heater is not working. After the taps, the pipelines through flexible plumbing hoses or rigid steel or plastic pipes must be connected to the branches from the tees on the mains.

Water supply without safety group with pressure reducer: 1 – water supply shut-off valves; 2 – water pressure reducing reducer; 3 – shut-off valves of the water heater; 4 – non-return safety valve; 5 – drainage to the sewer; 6 – valve for draining water from the tank; 7 – storage water heater

If the main water supply system requires pressure adjustment, then a reducer or a safety group is installed at the cold water inlet after the main taps or on the branches from the tees. As a rule, for domestic water heaters in urban conditions, it is sufficient to install a pressure reducer that reduces the pressure to the permissible or recommended by the manufacturer..

The safety group for an electric water heater consists of individual elements assembled on site. Not to be confused with boiler safety group! The order of their installation is shown in the figure..

Safety group assembly diagram: 1 – check valve; 2 – tee; 3 – “American”; 4 – safety valve FAR 6 bar; 5 – compression fitting for a metal-plastic pipe (drain when pressure is exceeded)

Scheme of water supply through the safety group: 1 – pressure reducer; 2 – valve for draining the tank; 3 – security group; 4 – drain into the sewer when the water pressure is exceeded

For horizontal water heaters, the connection is made according to similar schemes.

Diagrams for connecting the water heater to the mains

For safe operation, it is advisable to connect the water heater to the network in a dry place, and it is recommended to cover the cables in a moisture-proof channel. In addition to the boiler, other electrical appliances, especially powerful ones, should not be connected to this branch of the electrical network. The main elements of the circuit: electrical cable, socket, RCD and machine.

Cable

The cable section must be sufficient so that the wiring does not overheat and does not provoke a fire. You will need a copper three-core cable of the NYM brand or its analogue VVG. Recommended values ​​of the minimum cross-section of a copper conductor for different capacities of a single-phase water heater are given in table 1.

Table 1

Boiler power, kW	1.0	2.0	2.5	3.0	3.5	4.0	4.5	5.0	6.0	8.0	9.0
Minimum conductor cross-section, mm2	1	1.5	2.5	2.5	2.5	4	4	4	4	6	ten

Power socket

Small capacity water heaters can be connected directly to a three-wire waterproof outlet with a degree of protection against moisture in accordance with GOST 14254–96, for example, IP44 or another one that suits your situation (see table 2), which is installed on a separate supply from the electrical panel.

table 2

IP degrees of protection	IPx0	IPx1	IPx2	IPx3	IPx4	IPx5	IPx6	IPx7	IPx8
No protection	Falling vertical drops	Fall of vertical drops at an angle of 15 ° from the vertical	Splashes 60 ° from vertical	Splashes from all sides	Low pressure jets from all directions	Strong flows	Temporary immersion (up to 1 m)	Full immersion
IP 0x	No protection	IP 00
IP 1x	Particles > 50 mm	IP 10	IP 11	IP 12
IP 2x	Particles > 12.5 mm	IP 20	IP 21	IP 22	IP 23
IP 3x	Particles > 2.5 mm	IP 30	IP 31	IP 32	IP 33	IP 34
IP 4x	Particles > 1 mm	IP 40	IP 41	IP 42	IP 43	IP 44
IP 5x	Dust partially	IP 50				IP 54	IP 65
IP 6x	Dust completely	IP 60					IP 65	IP 66	IP 67	IP 68

Grounding socket

Such a socket outwardly differs from a two-wire one by the presence of metal contacts (terminals) of the ground.

Connection diagram for socket outlet with grounding

Protection devices – RCDs and circuit breakers

It is recommended to include a residual current device (RCD) in the electrical circuit for connecting water heaters (especially with increased power). It is designed to block the operation of the equipment in the event of current leakage to the case. The current strength at which the blocking occurs is indicated on the device and for the operation of the boiler must be 10 mA. This parameter indicates the difference between the current entering and leaving the water heater..

The choice of an RCD based on the capacity of the water heater is shown in Table 3.

Table 3

Water heater power, kW	RCD type
up to 2.2	UZO 10A
up to 3.5	UZO 16A
up to 5.5	UZO 25A
up to 7.0	UZO 32A
up to 8.8	UZO 40A
up to 13.8	UZO 63A

RCD type for AC mains – “A” or “AC”. When choosing a device, one should give preference to the more expensive, electromechanical one – it is more reliable, operates faster and provides higher protection..

In some boilers, the RCD is included in the basic package and is placed directly in the case, in other models it must be purchased additionally.

RCD appearance

Externally, the RCD and the differential switch (diffautomat) are very similar, but they are easy to distinguish by marking. A conventional machine turns off the current to the equipment when the voltage rises, and the differential one simultaneously performs the function of both the RCD and the machine.

The choice of a two-pole machine according to the power of a single-phase water heater is given in table 4.

Table 4

Water heater power, kW	Machine type
0.7	3A
1.3	6A
2.2	10A
3.5	16A
4.4	20A
5.5	25A
7.0	32A
8.8	40A
11.0	50A
13.9	63A

If overly sensitive protection devices are selected, the boiler will constantly turn off, and the water will not normally heat up.

Connection diagrams

The connection diagram is adopted depending on the desired level and instrumental performance of protecting people and equipment. Below are a few common patterns, as well as a video that provides detailed explanations of these patterns..

Connection only through the socket

Protection – double automatic machine: 1 – plug; 2 – socket; 3 – double machine; 4 – shield; grounding

Connection through the electrical panel: 1 – automatic machine; 2 – RCD; 3 – electrical board

In the RCD + double automatic circuit: 1 – RCD 10 mA; 2 – plug; 3 – socket IP44; 4 – double machine; 5 – water heater line; 6 – apartment line; 7 – electrical board; 8 – grounding

According to safety rules, all electrical work is performed with the power supply turned off at the individual electrical panel. Do not plug the water heater into the mains without filling it with water. Do not drain water from it without turning off the electricity.

Features of connecting a floor water heater

Since such a heater is installed on the floor, all connections to it are located not on the bottom panel, but at the bottom of the side or rear vertical wall. In everyday life, such storage boilers are rarely used, since the smallest of them have a tank volume of 100–150 liters. In addition, they take up a lot of space and have a lot of power, making serious demands on wiring and safety automation.

Water connection for floor-standing heaters is similar to wall-mounted models. Due to the relatively high power, the connection to the mains must be carried out exclusively through a separate panel..