Installing Outdoor Wood Boiler Step By Step Guide

February 8, 2023

Installing an outdoor wood boiler can be a great way to heat your home in an efficient and cost-effective way. However, it is important the installation is done properly to ensure that your outdoor wood boiler operates safely and efficiently. In this article, we will provide a step-by-step guide on how to install an outdoor wood boiler.

Read the manual, talk to dealers and find resources online

Read the manual for your wood boiler and if you do not have a manual contact your dealer. The manual will talk about how to layout your foundation, electrical needs, recommended setbacks, water treatment, warranty and many other items you should know before installation.  If you have any questions, reach out to a dealer or possibly the manufacturer to get clarifications on items in your manual. Looking online such as Facebook groups on outdoor wood boilers is another great resource to quickly find others who have faced similar circumstances.

Making the right call... To your insurance company

Call your insurance company verifying any requirements they may have.  Some insurance companies may require certain setbacks from insured buildings, different options on your insurance policy and may affect your insurability. Generally speaking, use the greater of either the manufacturer recommended or your insurance required distances for setbacks and clearances. In some instances, insurance companies may give you a break on your insurance bill as your heating source is outside of your home.

Find the right location

It is important to choose a location that is away from windows, doors, and other vents to prevent smoke and fumes from entering your home. Also make sure the boiler is not near a propane tank, fuel tanks, or other flamable sources. Placing wood boilers on the east side of any buildings will be preferred being on the wayward side of the prevailing winds. The location should also be level to ensure that the outdoor wood boiler operates properly and at a location easily accessible in winter to bring wood and regular loading, even when there is snow on the ground.  For running the underground pex lines, the location should have relatively direct access to the buildings to be heated and should consider crossing any underground utilities, hard surfaces, and root systems as it is recommended to bury at least 24" the direct contact of electrical wire. Don't forget to consider your neighbors and property lines with any setbacks on zoning.

Prepare the site

Once you have chosen the location for your outdoor wood boiler, it is important to prepare the site. Around and above the site should be clear of any combustible material and this is a good time to make firewood from problem trees. Make sure before placing the boiler that the foundation of the boiler is level. Best to put a concrete pad that has clearance around the sides boiler of at least 6" and infront of the boiler an extra 4'. Pay special attention to how the underground insulated pex will come into the stove and plan accordingly using the stove's plans in the manual.

As part of site preparation, inside the home validate a few items.  First, you should have an open breaker spot on your electrical panel to install a 15 or 20 amp breaker. If you do not have a spot, you may if electrical codes allow to double the breaker wire onto an existing circuit. Second, plan on where the underground pex will enter your home, either through a rim joist installation or through a core drill through the house foundation. Third, plan your runs from your water heater and/or home hvac system to the underground pex. Lastly, plan you route for getting power from your panel to the boiler electrical entrance into the house.  

Outdoor Installation of the system - Underground Pex

Generally, the outdoor installation of the system occurs first but it does not need to be this way and the inside can be done before the outside. When digging the trench for the underground insulated pex, it is best to trench down at least 24" but deeper is not necessary unless you are crossing a path that will have cars or heavy machinery crossing, then check with your underground pex supplier on their recommendations. There should be no pex connections underground as this will only lead to leaks. A pro tip to get the high quality foam filled pipe to come out straight is at each end of the trench dig down atleast 48" so the underground pex can be arched to come out of the ground straight up.

If it is a wide trench (more than 12"), you can lay the wire and the underground pex side-by-side with atleast 6" of separation. You can also stack the underground pex on top of the underground wire but have atleast 6" of clean fill between. Once the pipe is laid, a pressure test of the pex should be done to verify no leaks exist. When backfilling, try to pick out any rocks or sharp objects larger than a baseball as this can damage your underground pex.  Sand is the best option around your underground pex.  Pro tip to cap off the pex lines to prevent any dirt from getting into the lines.

See a post that covers more in depth on the process to Install Underground PEX

Outdoor Installation of the system - Boiler Connections

The boiler can be placed before or after the pex is burred but either way the underground insulated pex should go through the bottom of the stove and into the cabinet without any breaks. Pay special attention when dropping a boiler onto pex as this can cause damage. Once the underground pex is inside the back of the boiler, connect to the supply and return lines as instructed. If the boiler is on the same level as the house or is lower than the house, consider having your pumps on the back of the boiler. If the boiler is more than 10' higher than the house, then consider placing your pumps in the house. Also connect your underground wires to your boiler at this time also. Make sure all power is shutoff at the breaker and wires are tested before connecting the boiler.

Outdoor Installation of the system - Boiler Accessories

The next step is to assemble the accessories to the outdoor wood boiler. This will typically involve attaching a chimney to the main body of the outdoor wood boiler, adding any water gauge, and possibly other boiler accessories. Be sure to follow the manufacturer's instructions when assembling the outdoor wood boiler.

Connect the outdoor wood boiler to the heating and electrical system

The next step is to connect the outdoor wood boiler to your home's heating system. This will typically involve running pipes from the outdoor wood boiler to your home and connecting the hot water system. Be sure to follow the manufacturer's instructions when connecting the outdoor wood boiler to your heating system. Installing bypasses at all connections is critical to keep the systems in the house operational in the event there is a blockage or other type of issue with the boiler lines.

When installing into a forced air plenum, find a location that has good access from one side to install the forced air heat exchanger. Once located, cut a hole in the plenum the same size as the heat exchanger to slide into and install angle brackets to hold the heat exchanger into the plenum. The water to air heat exchanger should be as wide as possible but still allow for a smooth install. Once installed, seal any air inside the plenum or on the outside. You will need to also install a way to run the HVAC furnace fan when the water is hot from the boiler. Either an aqua stat connected to the heat demand wire (White) to either the heat wire (White wire) or the fan wire (Green Wire) will work. The other option is a a second thermostat located in the house setting this thermostat warmer than the regular HVAC house thermostat.

For water to water heat exchangers, basic plumbing will need to happen to get the water to flow correctly through the heat exchanger. Locate the cold supply that is going into the boiler. After that is located, find a good mounting place for the heat exchanger and install.  Bring the cold lines to the heat exchanger building bypasses as needed. For the wood boiler hot lines, the return cold water direction should run in he opposite direction than the boiler hot water.

Do not forget to connect your underground electrical to the home's electrical panel. Your home should have an open breaker spot on your electrical panel to install a 15 or 20 amp breaker. If you do not have a spot, you may if electrical codes allow to double the breaker wire onto an existing circuit. Then run a 120v rated electrical wire that is rated for your breaker from the panel to where the boiler will enter the home. Generally, the underground electrical panel will come in the same location as your underground pex.

Fill the outdoor wood boiler with water

Once the outdoor wood boiler is connected to your heating system, it is important to fill it with water. The water should be clean and free of contaminants to ensure that the outdoor wood boiler operates effectively and efficiently. Turn on the water pump and let the system run for a few minutes verifying all system components are working. Any bypasses should be opened and checked for leaks.

Light the fire

Once the outdoor wood boiler is filled with water, the next step is to light the fire. Make sure to follow the manufacturer's instructions when lighting the fire to ensure that it starts properly and generates enough heat to heat your home.

Monitor the outdoor wood boiler

After the fire has been lit, it is important to monitor the outdoor wood boiler to ensure that it is operating effectively and efficiently. This may include checking the temperature of the water in the outdoor wood boiler, monitoring the fire, and making any necessary adjustments.

Maintain the outdoor wood boiler

Regular maintenance is important to keep your outdoor wood boiler operating effectively and efficiently. This may include cleaning the firebox and chimney, checking the level of the water in the outdoor wood boiler, and replacing any parts that may have worn out over time. You may also need to run the chemicals in the boiler and after the first fire is lit and the boiler is up to temperature this is a good time to add chemicals. Some manufactures, such as crown royal stoves, will require annual water samples to keep the manufacturers warranty in affect.

Save money for years to come

By following these steps, you can install an outdoor wood boiler in a safe and effective way. Properly installed and maintained systems will last well over 20 years from manufactures who produce high quality outdoor wood boilers. Outdoor wood boiler can be a great way to heat your home in an efficient and cost-effective way, and by taking the time to properly install your outdoor wood boiler, you can ensure that it operates safely and efficiently for years to come.

It's also important to note that it's always recommended to consult with a professional for the installation of an outdoor wood boiler, especially if you're not familiar with plumbing and electrical systems. A professional can help ensure that the installation is done properly and in compliance with local codes and regulations.