Installing a combi boiler heating system involves several key steps that require technical expertise and adherence to safety guidelines. This comprehensive guide will walk you through the process in detail, providing a step-by-step playbook for a successful DIY installation.
Preparation and Planning
Before starting the installation, it’s crucial to ensure the property is protected from any potential damage. Verify the boiler’s compatibility with the existing heating system and gas supply, and check if the installation requires any special permits or licenses.
Boiler Compatibility Checklist
- Ensure the combi boiler’s BTU rating matches the heating and hot water demands of your home.
- Verify the boiler’s compatibility with the current gas supply line size and pressure.
- Check if the electrical circuit can handle the boiler’s power requirements.
- Ensure the existing plumbing can accommodate the boiler’s water connections.
Permits and Licenses
- Consult with your local building department to determine if a permit is required for the combi boiler installation.
- Hire a licensed and insured HVAC contractor if you’re not comfortable handling the installation yourself.
Mounting the Boiler
To mount the combi boiler, you’ll need to install a plywood panel on the wall to serve as a mounting surface. Attach metal mounting brackets to the plywood panel and then hang the boiler onto the brackets.
Plywood Panel Installation
- Measure and mark the wall where the plywood panel will be installed.
- Use a stud finder to locate the wall studs and mark their positions.
- Cut a piece of 3/4-inch plywood to the appropriate size.
- Secure the plywood panel to the wall using 3-inch wood screws, ensuring the screws are anchored into the wall studs.
Boiler Mounting
- Attach the metal mounting brackets to the plywood panel, following the manufacturer’s instructions.
- Lift the combi boiler and carefully hang it onto the mounted brackets.
- Ensure the boiler is level and securely in place.
Running New Lines
With the boiler mounted, you’ll need to run new gas, electrical, and plumbing lines to the plywood panel. Proper connections and adherence to safety standards are crucial at this stage.
Gas Line Installation
- Shut off the main gas supply to the property.
- Run a new gas line from the main supply to the combi boiler location, using approved gas piping materials.
- Install a gas shut-off valve near the boiler for easy access.
- Perform a gas leak test to ensure the connections are secure.
Electrical Wiring
- Locate the nearest electrical circuit that can handle the boiler’s power requirements.
- Run a new 240V, 30-amp electrical circuit from the circuit breaker panel to the boiler location.
- Install a dedicated circuit breaker for the combi boiler.
- Connect the boiler’s electrical cable to the new circuit, following the manufacturer’s wiring diagram.
Plumbing Connections
- Run new hot and cold water supply lines from the nearest plumbing fixtures to the combi boiler.
- Use copper or CPVC piping for the water connections.
- Install shut-off valves on the water supply lines for easy maintenance.
- Ensure all plumbing connections are properly sealed and leak-free.
Venting and Air Intake
Proper ventilation and air intake are essential for the safe operation of a combi boiler. Drill holes through the house wall to accommodate the exhaust vent and air intake vent, and use PVC pipe and fittings to create the vents.
Exhaust Vent
- Determine the best location for the exhaust vent, considering factors like proximity to windows, doors, and air intakes.
- Drill a hole through the exterior wall, sized to fit the PVC exhaust vent pipe.
- Install the PVC exhaust vent, ensuring it meets the manufacturer’s specifications and local building codes.
Air Intake Vent
- Locate the air intake vent near the exhaust vent, but at least 12 inches away.
- Drill a second hole through the exterior wall for the air intake vent.
- Install the PVC air intake vent, making sure it’s properly sealed and secured.
Connecting Water and Gas Lines
With the new lines in place, it’s time to connect the combi boiler to the water and gas supplies.
Water Line Connections
- Connect the hot and cold water supply lines to the combi boiler’s water inlet and outlet connections.
- Use copper or CPVC fittings to ensure a secure and leak-free connection.
- Insulate the water lines to prevent heat loss and condensation.
Gas Line Connection
- Connect the new gas line to the combi boiler’s gas inlet connection.
- Use approved gas pipe fittings and sealants to ensure a tight, leak-free connection.
- Perform a gas leak test to verify the integrity of the connection.
Installing Additional Components
To enhance the functionality and efficiency of your combi boiler heating system, consider installing additional components.
Outdoor Temperature Sensor
- Mount an outdoor temperature sensor near the combi boiler, following the manufacturer’s instructions.
- The sensor will help the boiler regulate hot water production based on outdoor temperature, improving energy efficiency.
Condensate Drainage
- Run a PVC condensate line from the combi boiler’s drain port to a nearby utility sink drain or floor drain.
- Install a condensate pump if the drain is not at a lower elevation than the boiler.
- Add a limestone neutralizer to the condensate line to prevent corrosion.
Final Checks and Testing
Before completing the installation, turn on the combi boiler and ensure it starts making hot water. Check the emissions and perform any necessary adjustments to ensure the system is operating safely and efficiently.
Startup and Commissioning
- Turn on the power and gas supply to the combi boiler.
- Verify the boiler is producing hot water and the heating system is functioning properly.
- Check for any leaks or unusual noises during operation.
Emissions Testing
- Use a combustion analyzer to measure the boiler’s carbon monoxide and carbon dioxide emissions.
- Adjust the air-fuel ratio if necessary to ensure the emissions are within the manufacturer’s specifications.
Old Equipment Removal
- Once the new combi boiler is installed and operational, remove and discard the old boiler and water heater.
- Properly dispose of any hazardous materials, such as refrigerants or asbestos, in accordance with local regulations.
Installing a combi boiler heating system requires a significant amount of technical expertise and attention to detail. While it is possible for a skilled DIYer to tackle the project, it is generally recommended to hire a licensed and experienced HVAC contractor to ensure the installation is done safely and in compliance with all relevant codes and regulations.
References
- CombiBoiler. (2017, October 21). How to Install a Combination Boiler Baxi Gas Combi Boiler Installation. YouTube. https://www.youtube.com/watch?v=5GHT834JUOY
- Navien. (2023, July 23). Combi-Boiler Installation. https://www.navieninc.com/blog/notice/combi-boiler-installation
- This Old House. (2015, November 14). How to Install a Combination Boiler/Water Heater | Ask This Old House. YouTube. https://www.youtube.com/watch?v=BuxvKbIIYLU