The purchase of a tankless electric water heater specified in is only the first step. The device must also be installed correctly in your home.
This work requires good plumbing and electrical skills and is probably best done by a recognised professional (even mandatory in some areas).
However, if you prefer to install your new do-it-yourself water heater, you should be prepared to spend a few hours on the entire installation.
Do you want to know all the details? The following manual explains step-by-step how to install an electric water heater without a tank.
- Requirements for the installation of an electric boiler without tanks
- Electrical maintenance requirements
- Water pressure requirements
- Where to install
- Tools and accessories
- How do you install an electric standby-boiler yourself, step by step?
- Installation video
- Additional remarks
- Insulation of hot water pipes
- Water recycling plant
Installation requirements for floating electric water heaters
What are the requirements for installing an electric water heater without a tank?
Electrical maintenance requirements
Not all houses are equipped with an electric boiler without tanks for the whole house. Indeed, the suction of an amplifier in such a system is simply too high. For example:
The Stiebel Eltron Tempra 36 Plus requires 3 separate 50A bipolar switches and a recommended main power supply of at least 300A. In the future, the average house will have a total capacity of 200A.
This could mean upgrading your old switchboard with large cables and large switches, or commissioning a brand new switchboard, which would require a few thousand dollars in electrical work.
FOR YOUR INFORMATION: The Stiebel Eltron Tempra 36 Plus can deliver 5.45 gallons per minute at outlet temperatures of 59°F and 105°F.
Stiebel Eltron Tempra 36 Plus – available at amazon.com.
The Tempra 24 Plus, which is slightly smaller, still needs 2 x 50A bipolar switches and 150A main service.
An electric boiler without a tank (POU) should not be a problem with current requirements. While most of them require 240V, some very small POUs can operate at 120V.
How do you determine the current in your home? Check the electrical switch, which is normally located outside the house. You can also search for a label in your control panel. The other possibility is to ask the electrician.
Water pressure requirements
Most electric tankless boilers can operate in a pressure range from 30 to 150 psi. If the supply water pressure is higher than 150 psi, a pressure reducing valve must be installed for heating.
As the owner, you may generally install the boiler yourself. In most states, however, you still have to get permission to have them checked for security reasons. It is also intended to replace the old boiler.
An installation inspector comes to your home and examines the installation to make sure that the work is carried out properly.
Where to install
The first step is to find a suitable wall for the installation of the boiler. For the whole house, it is a good idea to place the boiler next to where most of the hot water is consumed. This way you will get hot or warm water faster when you open the outlet (whether or not you are using a circulation pump; see below for more information). At the same time, you must have access to the main cold water pipe.
In the case of point of use systems, it is necessary to place them as close as possible to the point of use so that the water can be drained in good time.
The good news is that electric boilers do not need to be vented. And since we don’t have a storage tank, we can choose a place that doesn’t fit in a tank device – remember, a small bathroom or even under the sink.
Don’t forget that most electric water heaters without boiler must be installed vertically, with the electrical and hydraulic connections down. In addition, there must be a minimum distance for maintenance.
In general, you should avoid places where
- Your boiler is normally sprinkled with water or other liquids.
- There may be frost.
Excessive humidification and humidity are just as problematic.
Otherwise, your product warranty may become invalid.
Tools and consumables required for the successful installation of a new electric water heater without a tank may include the following:
You haven’t bought the system yet? Don’t forget to check out our reviews of our electric tankless boilers to find the best! Here you can learn how to correctly dimension an electric water heater without a tank.
- Drill + drill bits
- Flat head screwdriver
- Phillips screwdriver
- Needle Pliers
- Adjustable wrench
- Pipe cutter
- Tape measure
- Mounting screws and anchors (must be supplied with the system).
- ¾ or ½ (e.g. copper tube or flexible stainless steel tube).
- Reduction valve
- Temperature and pressure relief valve (T&P)
- teflon tape
- Pipe insulation
- Bipolar circuit breaker
- Wire + Earth
- Circulation pump + relief valve
You may also need tools and accessories for welding or soldering.
Installation of a special electric boiler step by step
Please note that these step-by-step installation instructions are only given as an example before you start work. The requirements for a particular boiler may vary. It is therefore essential that you read all instructions for use.
In addition, incorrect installation may invalidate the warranty, shorten the life of the system, and cause serious injury or death. So if you don’t know what you’re doing, do yourself a favour and hire a qualified electrician and plumber to do the installation for you. The work is too dangerous and not worth saving a few hundred dollars.
It should be noted that some manufacturers have to have their systems installed by a licensed contractor, otherwise the warranty will automatically expire.
Finally, if you have any questions about the installation, please call technical support.
Disclaimer of liability: It is recommended that this work be carried out by a qualified professional. In addition, the installation shall comply with all national, state and local electrical and sanitary codes and standards.
- Start by switching off all the circuit breakers involved.
- Turn off the main water supply.
- If necessary, the old boiler must be drained and switched off.
- Remove all screws securing the front of the device to be installed. Take the lid off, but be careful: You may need to remove one or more connectors before you can set them aside.
- Install the electric water heater without tank on the wall. Screws and anchors must be supplied with the delivery.
- Now it is time to install a connection for cold water (usually on the right) and hot water (usually on the left). Perhaps the easiest way is to use a flexible stainless steel tube (¾) in combination with Teflon tape. A copper or PEX tube (which must be designed for high temperatures) can also be used. It is just that some boilers are equipped with a sieve on the cold water inlet, which needs to be cleaned from time to time. It is therefore important that the cold water connections can be easily removed. If you have to cut the pipe, clean the edges. When welding or soldering, ensure that the pipes are flushed thoroughly before connecting them to the boiler, as excessive heat can damage the unit.
- It is advisable to install a shut-off valve before and after the heating, so that the water supply to the heating can be shut off for repair work, etc., without blocking the water supply to the rest of the house.
- It is also a good time to install a pressure regulator on the cold water side if the incoming water pressure exceeds a certain threshold (more details). A thermostat and safety valve (T&P) installed on the hot water side is not required unless required by local or national installation regulations.
- Open a few hot water outlets for a few minutes to drain the air from the pipes and the boiler. In the meantime, you can check all connections for leaks. Turn off all power sockets.
- Attention: Refer to the wiring diagram in the manual! The next step is the electrical connection of the boiler on one side and the electrical control panel on the other side. For the correct number and size of wires and circuit breakers, see the manufacturer’s instructions. Small devices can be connected to a circuit, for example with a 6/2 AWG wire set and a grounding protected by a 50A bipolar circuit breaker. Larger devices require two or even three separate circuits and possibly a thicker wire. Cut and strip each set of wires, insert them through the lower holes in the water heater housing and secure them firmly in the appropriate slots in the terminal block (refer to the manufacturer’s instructions for optimum torque). For each circuit, an earthing conductor must be connected to the earthing rod of the equipment and to the earthing panel.
- Check all electrical connections. Be careful when mixing the different sets of wires.
- Attach the system cover.
- Turn on the breakers.
- Your electric boiler without a tank should be on by now. Configure it according to your needs, for example by setting the water temperature to the desired level.
- Open the hot water spout. Wait until the temperature stabilizes. Check the temperature and adjust if necessary.
- Let’s go, let’s go, let’s go, let’s go!
Do you prefer video? You might need it:
Finally, a few remarks:
Insulation of hot water pipes
Hot water pipes with a small overhang of the heating system should be insulated to protect children from burns.
Water recycling plant
Even with a tankless boiler, also known as a continuous water heater, you do not have direct hot water when you turn on the kitchen tap or other drain. This is because the hot water in the pipes eventually cools down when not in use.
Fortunately, there is a solution: Circulation pump. The circulation pump brings the cooled water back to the heater to heat it up. It has certain advantages:
- Just wait a few seconds for hot water.
- Water consumption is almost nil, as no litres of cold water have to be thrown into the drain.
How does a recirculation pump work? Most use a sensor to measure the temperature of the water near the heater or a specific device. The pump is activated as soon as the water temperature falls below a certain threshold value.
How can the water come back? There are two possibilities:
- Your house already has a recycling line (special return line) or you install it at quite a high cost.
- Install the cross flap, preferably in the bracket furthest away from the stove. This non-return valve connects hot and cold water. It opens and closes depending on the water temperature. In this way the cold water can flow out through the cold water pipe and back to the heating system.
You have to think: A circulation pump in combination with a tankless boiler would lead to an enormous loss of energy due to frequent pumping and heating. And you were right not to use some kind of intelligent control.
Intelligent control – this can be a timer, a button, a motion sensor, a remote control – ensures that the pump is only activated at a certain time of day, for example just before it wakes up in the morning.
Circulation pumpwith timer and thermostat – available at amazon.com.
Another aspect to take into account is the volume of the pump. A pump with a too low flow rate cannot activate the heating.
If you want to know more, you can check this pump with timer + built-in thermostat or this model that can be started with the remote control.
If you have any questions about the installation of an electric water heater without a tank, please leave a comment below!
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