Using a boiler to heat your home (or furnace) will require the use of a heat exchanger. The heat exchanger is installed inside either of these heating units and its purpose is to exchange heat with either air (in a forced air system) or water (in a radiant heat system). There are several ways in which the heat exchanger does this job. The 2 elements can run together in the heat exchanger or exists apart but run close together so the heat is exchanged. Over time a heat exchanger can fail and you can replace it yourself and this article will show you how.
Step 1 - Safety
When you work with a furnace or boiler you need to take just as many precautions as you would when working around electrical wiring. Disconnecting or accidentally puncturing a pipe or hose can cause a stream of steam bellowing toward you. This will surely send you to an emergency room. Prior to replacing the heat exchanger you should turn the electric off at the main breaker. Give the furnace or boiler time to cool down before around it. It is a good idea to replace a heat exchanger when the weather outside is warmer. Be sure to wear work gloves as you'll be working around sharp edges and getting cut is easy to do.
Step 2 - Access to Heat Exchanger
The boiler or furnace houses the heat exchanger and you need to go through it in order to get access to the heat exchanger. Locate the screws on the front of the boiler or furnace. There may be several sets of screws. If there are several sets of screws then remove them all. Once the screws are removed you can remove the metal panels. You may need to use a screwdriver to pry them free. Work in sections and place the screws inside the holes of the plate they came from as you remove them so you do not lose screws. The heat exchanger resembles a metal plate and will have tubes coming off of it.
Step 3 - Replacing the Heat Exchanger
Before you begin removing the heat exchanger always take notes of where everything is attached and the orientation of the heat exchanger. If you purchased an identical heat exchanger to the old one (always the best idea) then reconnecting it will be simple. Consult the manual of a new heat exchanger if it is different as you may need to make adjustments to the fittings inside the boiler or furnace.
Use the screwdriver and wrench to remove the fittings attached to the heat exchanger. Once they are removed, the heat exchanger should be able to be pulled free rather easily. Put it off to the side and slide the new heat exchanger into place. Start replacing the fittings and tighten them as needed. Once the new heat exchanger is in place you can replace the panels and turn the power back on. The system will need time to prime itself before operating.