I recently bought my first home, and the first thing we noticed is that the dynamic hot water pressure is pretty low compared to the cold water pressure. I purchased a water pressure gauge and found that the static hot water pressure is identical to the cold water static water pressure (about 95 PSI). When I turn on a cold tap, the dynamic cold water pressure reads at about 85 PSI, which is totally cool. When I do the same for the hot water, it drops waaay waaay lower.
When I attached a hose to my water heater to try to flush it, the water pressure was amazing, and the water was perfectly clear. So it doesnt appear to have a sediment problem.
Basically this results in a low hot water flow rate for the entire house. The water heater (probably near the end of life) is a 40 gallon gas heater. Any idea what might be causing this? Anyway I can try to fix this with out having to buy a new water heater or call a plumber?
Best Answer
There is a restriction, somewhere. You could use your gauge to verify that the pressure (while you are flowing from faucets) at the water heater is good (you've only done so qualitatively so far, and you have means to test it quantitatively, so....) But basically somewhere in the line is something that is restricting water flow - perhaps a clogged or under-sized tempering valve (if there is a tempering valve) or the one I keep mentioning because it was a bear to track down and semi-unbeliveable when I did, an elbow almost completely plugged with solder. Could also be pipes plugged with mineral deposits.
If you open the hot faucets and pressure at the water heater stays good, move the pressure test up the line - somewhere it will get worse, and between there and the last place it was good is the problem.
Incidentally, 95 PSI is on the high side for many fixtures - you might want to add (or adjust if there is one) a pressure reducing valve and get to down to 75-80 PSI MAX.