How To Install a Combination Boiler Water Heater

A combination boiler and water heater, also known as a combi boiler, is a heating system that provides both heat and hot water for small to medium-sized homes. This unit combines the functionality of a boiler and a hot water heater to save space savings and improve efficiency. This Old House plumbing and heating expert, Richard Trethewey, demonstrates the installation process and explains how a combi boiler works.

Understanding Combi Boilers

Combi boilers are gaining popularity due to their efficiency and space-saving design. These units eliminate the need for separate heating and hot water systems, streamlining your home’s mechanical setup into one space.

A combi boiler uses a heat exchanger to warm water for home heating and hot water use. When you turn on a hot water faucet, the boiler detects the flow and quickly heats the water as it passes through the unit. For home heating, the boiler circulates hot water through your existing radiators or baseboards.

Advantages of Combi Boilers

Combi boilers have many benefits over traditional heating systems, including the combination of two systems into one to free up space in your home. These units only heat water when needed, reducing energy waste. You also get an endless supply of hot water without needing a storage tank. Also, with fewer components, combi boilers are usually easier to maintain than separate systems.

Preparing for Installation

Before installing a combi boiler, you need to prepare your space and gather materials.

Choosing the Right Location

Select a suitable location for your combi boiler, considering factors such as the proximity to existing gas and water lines. You also need to consider adequate ventilation and easy access for maintenance. Most importantly, you must keep a safe distance from windows and other openings for venting purposes.

Gathering Materials and Tools

You have to collect all the required materials and tools before starting the installation:

• The combi boiler unit
• Mounting brackets and hardware
• PVC piping for venting
• Gas and water piping
• Electrical wiring and conduit
• Plywood for mounting (if necessary)
• Various hand tools and power tools

Installation Process

Installing a combi boiler is a complex task that requires technical expertise. While the video demonstrates the process, this job should be performed by a licensed professional for safety and code compliance reasons.

Mounting the Boiler

1. Secure a plywood panel to the wall where the boiler will be installed.
2. Attach the mounting brackets to the plywood panel.
3. Carefully lift and hang the combi boiler onto the brackets.

Venting Installation

Proper venting matters for the safety and correct operation of your combi boiler:

1. Drill two 4-inch diameter holes through the exterior wall for exhaust and air intake.
2. Install PVC piping for the exhaust and air intake vents.
3. Check for proper clearances from windows and other openings to maintain a safe distance between the intake and exhaust vents.

Connecting Plumbing and Gas Lines

Once the boiler is mounted and vented, the next step is to connect the plumbing and gas lines:

1. Run new gas, electrical, and water lines to the boiler location.
2. Connect hot and cold water lines to the combi boiler.
3. Install a properly sized gas line connection.
4. Set up the condensate drain line and a limestone neutralizer to manage acidity.

Electrical Connections

The final step in the installation process involves making the electrical connections:

1. Install an electrical circuit for the boiler.
2. Connect the boiler to your home’s electrical system, following all local codes.
3. Install and connect an outdoor temperature sensor.

System Testing and Activation of Combination Boiler Water Heaters

After installation, you need to test the system before regular use.

Initial Start-up

Turn on your water supply and check for any leaks in all connections. Activate the gas supply and test for any gas leaks. Power on the boiler and observe the initial start-up sequence.

Performance Checks

Once the system is running, check that hot water is available at all fixtures and test the heating function by adjusting the thermostat if needed. Make sure the ventilation system is working properly by checking for any unusual noises or odors.

Boiler Safety and Efficiency Improvements

In addition to the installation, you should consider long-term safety and efficiency measures, including securing the vent and upgrading aspects of your combi boiler.

Securing Venting Safety

The safe operation of your boiler involves proper venting strategies. Installing vent screens can prevent any obstructions caused by debris. Regularly check the positioning and seal of the PVC venting pipes to avoid leaks and damage.

Enhancing Boiler Efficiency

Upgrading to programmable thermostats and utilizing the outdoor temperature sensor helps optimize your boiler’s performance. These devices regulate heat based on external conditions throughout the year. Regular flushing of the heat exchanger can prevent scaling and sediment buildup for good heat transfer. In some cases you may also be able to use your combi system with a heat pump water heater.

Maintenance and Care

To keep your combi boiler running efficiently, perform regular maintenance and professional servicing.

Routine Checks

Even with a reliable system, routine maintenance checks help for longevity and performance. Don’t overlook minor issues since early detection can prevent significant problems. Inspect the venting pipes every few months to make sure there are no obstructions or damage. Monitoring your boiler’s water pressure helps to make sure it stays within recommended levels.

Professional Servicing

While routine self-checks are helpful, scheduling annual professional maintenance is equally important. Professionals can clean and inspect internal components, check and adjust gas pressure, and assess your system’s overall efficiency. They can also verify that all the safety controls are functioning correctly.

Advancing Technology in Combi Boilers

As technology advances, newer models of combi boilers are becoming even more efficient and user-friendly for homeowners.

Smart Home Integration

Many modern combi boilers are now compatible with smart home systems. These systems allow you to control and monitor your boiler remotely, adjust temperatures, and receive maintenance alerts through your smartphone.

Environmental Considerations

Newer combi boilers are designed with eco-friendly features that reduce their impact on the environment. Look for units that meet high-efficiency standards and have low NOx emissions.

Advanced Diagnostics

Many combi boilers come with diagnostic capabilities. These units can self-diagnose issues and provide error codes, which can save you time and money on repairs by determining the exact problem.

Remember to consult with a licensed professional for a safe installation, proper maintenance, and what technology features are best for your home and lifestyle.