How To Fill Your Outdoor Furnace and Purging Air From a Central Boiler

Video Transcription: How To Fill Your Outdoor Furnace and Purging Air From a Central Boiler

We're going to cover the three most important things to remember when adding treated water to your furnace. On this easel over here, I've laid them out for you to look at. You must remember treat, purge, and heat. First thing you must do is you must treat the water with corrosion inhibitor and moly boost. Second thing is you must purge any air in the system

using domestic water pressure. And thirdly, you must heat up the outdoor furnace to kill any

microbes that may be hanging around. It's pretty easy, we're going to show you how to do it.

The first thing you'll have to do is remove the shipment securing wire from the vent cap before adding water treatment. Before any water is added to the furnace, you need to add inhibitor plus and moly boost. See the owner's manual for your furnace to see how much you need. When replacing the vent cap, make sure it fits loosely. Now that we've added water treatment to the water jacket, we're going to fill the system with water and purge the air as outlined in the installation guide.

Now we've set up a little demonstration station here and you can see we have our outdoor furnace hooked to the indoor system through the thermal packs, our water heater with our sidearm kit to heat your domestic water, and a forced air system. First thing we're going to do is add water to the furnace. Now at the furnace, determine your supply, which includes the circulator pump, and your return line, which is marked here. Make sure the circulator pump is unplugged and we want to make sure that both valves are closed on supply and return. When the valve lever is in line with the water line, that is open. When the valve is perpendicular to the water line, that is closed.

Now we're going to actually add water to the furnace. We're going to use this washing machine hose with two female ends and we're going to hook one end up here to the top of the water here through a backflow preventer. That's your domestic water supply and we'll hook this end of the washing machine hose right here. This connects to your outdoor furnace water. Now we're going to add water to the furnace. First thing we'll do is open up the pressurized domestic water spigot on top of the water heater. Then we'll open up this valve here, which gives us access to our outdoor furnace water. Then go over to the furnace and we're going to open the supply line valve right here. This will push all the water and all the air out to the supply line.

After about five minutes, then close the supply line and open the return line. Again, this will push all the water and air out the return line into the outdoor furnace. We're just going to let the water run now until it fills up the furnace and is about one inch below the full mark on the sight gauge on the back of the furnace.

Now the furnace is full, so we're to close off this valve here, the return line on the outdoor furnace. Then go into the house and turn off the point where you are putting water in the outdoor furnace line and turn off your pressurized domestic water spigot.

At this point, go back out to the furnace. You can open these two valves, those return and the supply, and at that point plug in the circulator pump to circulate the water throughout the system. Now it's very important to fire the furnace to heat the water up to set point. This needs to be done to kill any microbes that might be in the water jacket that could potentially eat up the inhibitor.

So make sure you get it to set point even if you're not going to run the furnace until a few months from now. Here's an example of an installation where the person obviously enjoys paying for their hot water and chose not to hook up our sidearm exchanger on the water heater.

Now that's fine, but you still need to purge the air out of your system using domestic water pressure. So during the install, make sure you put a hose bib or a boiler drain in line with the outdoor furnace water. In that case, you can use a washing machine hose and extend it over to a laundry tub or any pressurized domestic water source with a garden hose. And finally, after the water's been heated and circulated for 24 hours, perform a water test with a test kit that came with your furnace.

For more information and additional videos, see centralboiler.com.