How to Properly Install a DAFI Water Heater?  - A Complete Step-by-Step Installation Guide

How to Properly Install a DAFI Water Heater? (Installation Requirements Overview)

How to Prepare for Installing a DAFI Water Heater?

Before you even start installing your DAFI water heater, it’s crucial to prepare properly. This ensures you don’t make mistakes that could cause the unit to malfunction or be inefficient.

The first and most important rule – install the heater as close to the point of water use as possible. This minimizes heat loss and improves heating efficiency. The longer the pipe from the heater to the tap, the greater the heat loss and the longer you’ll wait for hot water.

Next, water pressure is key. The manufacturer specifies a range: minimum 0.6 bar, maximum 6 bars. If your home's water pressure is too high, you must install a pressure-reducing valve. Otherwise, the heater’s durability could be compromised.

If you use well water, installing a water filter is a good idea. DAFI flow heaters don’t work well with contaminated water, as impurities can accumulate on the heating elements and gradually reduce efficiency.

Also, check your electrical system’s parameters before proceeding—more on this in the next section.

Electrical Connection – What You Need to Know

No room for improvisation here—proper electrical installation is critical. The DAFI heater must be installed by a qualified electrician, not only to ensure it works correctly but also for your safety.

First and foremost, DAFI heaters above 3.7 kW must be permanently connected. This means they cannot simply be plugged into a standard outlet. You need a dedicated circuit with a proper circuit breaker and a residual current device (RCD).

Required cable cross-section depends on the unit’s power:

• 3.7 kW – 2.5 mm²
• 4.5 kW – 2.5 mm²
• 5.5 kW – 4 mm²
• 7.3 kW – 4 mm²
• 7.5 kW and above – 6 mm²

Every heater must be properly grounded—this is non-negotiable. Ignoring this step significantly increases the risk of electric shock.

If your home has an older electrical system, consult an electrician before installation to ensure it can handle the required load.

Connecting the DAFI Water Heater to the Plumbing System

Once the electrical setup is sorted, it’s time for the plumbing. Connecting the water supply isn’t overly complex, but there are a few critical rules to follow.

First, the heater must be connected to the cold water supply. This may sound obvious, but mistakes happen—some people mistakenly connect it to the hot water line and wonder why it’s not working.

If you’re installing an under-sink DAFI model, you can mount it in any position, as long as the water flow direction matches the markings on the unit.

Secure the heater to the wall or under the sink using the mounting screws provided in the kit to ensure stability.

If the water pressure in your home exceeds 6 bars, installing a pressure reducer is mandatory.

Before turning on the heater, make sure to purge air from the system—failure to do so can damage the heating element.

First Startup – What to Watch Out For?

The first startup is a crucial moment, requiring caution and adherence to the manufacturer’s instructions.

Key steps:

1. Water first, then power – Before plugging in the heater, open the tap and allow water to flow through the unit for a minute to remove air.
2. Check for leaks – Before switching it on, make sure all connections are tight and there are no leaks.
3. Adjust the water flow – If your model has a flow adjustment feature, set it to get the desired temperature.
4. Power up and test – Once everything is set, connect the heater to the power supply and test if it works correctly.

Common Installation Mistakes and How to Avoid Them

People often make the same mistakes, so it’s good to know what to avoid:

• Incorrect water pressure – If your home has high water pressure and you don’t install a reducer, you risk damaging the heater.
• Improper electrical connection – No grounding, cables that are too thin, or no RCD can lead to serious problems.
• Skipping the air purge – If you don’t let water flow through before turning it on, the heating element may burn out.
• Wrong placement – Installing the heater too far from the water outlet increases heat loss and energy consumption.
• Excessively long power cable – A cable that’s too long can cause voltage drops, affecting heater efficiency.