First, if you have a boiler, check the pressure on the system.  Almost all hot water boilers should be between 10 to 18 PSI.  If the pressure goes too low, air can—and will—get into the baseboards, especially if the house is more than one story. Air can also get into the slab heating system, which causes the flow of the heating medium to slow. It may stop flowing completely if the pressure gets down to around zero PSI, and you’ll need boiler repair to get it running again. 

As a home owner, or even a renter, it is a good idea to check the gauge on the boiler to see what the pressure is at least two or three times a year.  A good heat tech will check the pressure when they do a tuneup or perform boiler repair, but it can be at least a year between tuneups.

Second, if the pressure is going too high and the relief valve is popping off, or if you find the pressure on the system is up around 30 PSI, something is probably wrong. If the relief valve starts to pop off every time the boiler fires, the expansion tank has more than likely failed.  Expansion tanks have a rubber baffle in them, like an innertube with pressure behind it.  Usually the pressure in it is between 8 and 10 PSI.  If and when they fail, the rubber baffle gets a hole in it and the fluid goes in where the air is supposed to be. 

Because fluid in the heating system expands when it is heated, it has to have somewhere to go since neither water or glycol can be compressed.  Most boilers go from 140 degrees up to 180 degrees, so there is a lot of expansion and contraction in a hot water heating system. This is one of the reasons units fail over time and require boiler repair.

Any leak on a boiler system is a very bad thing.  If you are using only water in the boiler, the fill system is supposed to add water to get the pressure back up to 12 to 14 PSI every time there is a leak. When fresh water is constantly added to a boiler system because of a leak somewhere, it is also adding oxygen to the system in that water. This will cause the boiler to rust from the inside out, which is the second reason boilers fail. So, if you have a leak on your system, you’ll need boiler repair sooner than later.

Hopefully this will help you—we’ll have some more information next month!

If your boiler fails this winter and you need boiler repair, call the dependable team at Gary’s Repair & Burner Service. With over 30 years of service, these professionals are ready to help keep you warm and comfortable in your home. Get in touch with their team at (907) 474-0736 or visit them online.