Hi all,
Sometimes (but not all the time), when I first open a faucet, the water pressure is momentarily higher than normal for about 3-5 seconds. This short burst of higher pressure is not extreme but is definitely noticeable.
Here are a few relevant facts about my system:
1. I have a pressure reducing valve after the water meter set to 50 PSI.
2. I have a water pressure gauge installed on the cold line immediately above the water heater that shows a constant ~50 PSI.
3. I have an expansion tank installed on the cold line next to the water heater with the air bladder pressurized to 50 PSI.
4. I replaced all of the old galvanized pipe with Uponor ProPex (PEX-A).
5. The water heater's TPR valve is not opening or leaking.
I believe the momentarily high water pressure occurs when the water heater has caused thermal expansion and a faucet has not yet been opened to release the pressure. I also believe that the purpose of an expansion tank is to mitigate this issue, and the ~50 PSI I observe on the pressure gauge seems to confirm that the expansion tank is operating as designed. So why am I still observing the momentary burst of water pressure when first opening a faucet?
I have three guesses:
1. The expansion tank is doing its job and filling with a small volume of water. When I open a faucet, the initial burst of water occurs because the air bladder in the expansion tank has become pressurized to more than 50 PSI by the expanded water. The pressurized air bladder therefore pushes the water out of the expansion tank in a relatively short burst as the air bladder returns to 50 PSI.
2. The expansion tank is doing its job and filling with a small volume of water, but the flexible PEX-A lines are also absorbing some of the thermal expansion similar to the expansion tank. When I open a faucet, the initial burst of water occurs because the PEX-A lines are releasing the thermal expansion.
3. Both of the above are occurring.
Is it normal to observe momentarily high water pressure when opening a faucet, even with a thermal expansion tank installed? If so, are my explanations for why this occurs correct?
Thanks for reading!
Sometimes (but not all the time), when I first open a faucet, the water pressure is momentarily higher than normal for about 3-5 seconds. This short burst of higher pressure is not extreme but is definitely noticeable.
Here are a few relevant facts about my system:
1. I have a pressure reducing valve after the water meter set to 50 PSI.
2. I have a water pressure gauge installed on the cold line immediately above the water heater that shows a constant ~50 PSI.
3. I have an expansion tank installed on the cold line next to the water heater with the air bladder pressurized to 50 PSI.
4. I replaced all of the old galvanized pipe with Uponor ProPex (PEX-A).
5. The water heater's TPR valve is not opening or leaking.
I believe the momentarily high water pressure occurs when the water heater has caused thermal expansion and a faucet has not yet been opened to release the pressure. I also believe that the purpose of an expansion tank is to mitigate this issue, and the ~50 PSI I observe on the pressure gauge seems to confirm that the expansion tank is operating as designed. So why am I still observing the momentary burst of water pressure when first opening a faucet?
I have three guesses:
1. The expansion tank is doing its job and filling with a small volume of water. When I open a faucet, the initial burst of water occurs because the air bladder in the expansion tank has become pressurized to more than 50 PSI by the expanded water. The pressurized air bladder therefore pushes the water out of the expansion tank in a relatively short burst as the air bladder returns to 50 PSI.
2. The expansion tank is doing its job and filling with a small volume of water, but the flexible PEX-A lines are also absorbing some of the thermal expansion similar to the expansion tank. When I open a faucet, the initial burst of water occurs because the PEX-A lines are releasing the thermal expansion.
3. Both of the above are occurring.
Is it normal to observe momentarily high water pressure when opening a faucet, even with a thermal expansion tank installed? If so, are my explanations for why this occurs correct?
Thanks for reading!