An expansion tank is necessary for water heaters, because the process of heating water causes it to expand. Without an expansion tank, pressure could build to unsafe levels
All tanks are equipped with a safety release for the pressure and the only time when that delta in pressure can be problematic is when you go from completely cold to hot due to the higher amount of water that can fit in the tank at lower temp.
Otherwise I’ve never seen a house in Canada with an extension tank attached to the water heater and the water come in ice cold in the winter.
Well, right up until the pressure relief valve fails. Whether it fails open or closed, you’re gonna have a bad time, because either way you’re probably going to have a lot of water where there’s not supposed to be water.
If you are on municipal water and there is no check valve between you and the water meter then the municipal water supply is acting as the expansion tank. It may not be to code in your area but that’s how many homes were built in the past.
Honestly, I don’t know, I’m not a plumber. There are a couple possibilities, including that it was built into the water heater or the relief valve did it’s thing. Some water heaters don’t need expansion tanks at all, either. It’s generally a “just in case” thing, since the right failures in the wrong way could lead to a hot water bomb going off in your house.
In reading it looks like it is for homes newer than 1986? Our old water heater was 20 years old and we never had any issues with the pressure getting too high.
An expansion tank is necessary for water heaters, because the process of heating water causes it to expand. Without an expansion tank, pressure could build to unsafe levels
All tanks are equipped with a safety release for the pressure and the only time when that delta in pressure can be problematic is when you go from completely cold to hot due to the higher amount of water that can fit in the tank at lower temp.
Otherwise I’ve never seen a house in Canada with an extension tank attached to the water heater and the water come in ice cold in the winter.
Pressure won’t build up, it will be let out by the pressure relief valve and make a mess on the floor. Which is also undesirable.
Well, right up until the pressure relief valve fails. Whether it fails open or closed, you’re gonna have a bad time, because either way you’re probably going to have a lot of water where there’s not supposed to be water.
If it’s necessary then how did my last tank make it 20 years without one?
If you are on municipal water and there is no check valve between you and the water meter then the municipal water supply is acting as the expansion tank. It may not be to code in your area but that’s how many homes were built in the past.
Honestly, I don’t know, I’m not a plumber. There are a couple possibilities, including that it was built into the water heater or the relief valve did it’s thing. Some water heaters don’t need expansion tanks at all, either. It’s generally a “just in case” thing, since the right failures in the wrong way could lead to a hot water bomb going off in your house.
Yeah but that was like the coolest mythbusters episode ever /s
In reading it looks like it is for homes newer than 1986? Our old water heater was 20 years old and we never had any issues with the pressure getting too high.