Drained water heater twice but still low pressure

Old 02-21-21, 04:04 PM
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Drained water heater twice but still low pressure

In the past week we drained our gas hot water heater (Rheem 50 gal, 17 years old) twice because of very low hot water pressure. It seemed to work when my husband did it the first time, but then a few days later, the hot water would gush out and then quickly go down to practically nothing.

Yes, we realize that 17 years is old for a water heater (and we have very hard water), but is this definitely a sign of needing a new one? My husband is wondering if there is anything else he can check to get the water pressure back up to normal--easy for a non-DIYer. Or is it time to call in a plumber to take a look?

Old 02-21-21, 04:28 PM
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Possibility #14: Something, maybe a pebble that came up from the town water main, bouncing around in a pipe and sometimes lodges maybe just in front of a shutoff valve or a water heater heat trap, and blocks the flow. You will have to find it and then remove it.One brute force way of trying to find the blockage is to cut the hot water line here and there, starting with before the cold inlet to the water heater, and testing for gushing water out of the open end. Then use a section of hose to join it back together (possible need to reopen and retry a place you tried before) and try another place further downstream to cut the pipe and repeat the gushing test. Then, after you find the blockage, solder on pipe couplings to join all of the cut pipe end pairs back together.
Bham45 voted this post useful.
Old 02-21-21, 05:08 PM
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I'd agree with Allan. I wouldn't think the water heater would be the cause of low water pressure. There's nothing really in a water heater to affect the pressure.
Is there any tempering valve or anything other than a standard shutoff valve into or out of the water heater?
Old 02-22-21, 05:18 AM
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Draining a water heater does not improve flow volume. In fact it sometimes disturbs sediment that clogs a fitting or valve causing a flow problem.

Is your hot water pressure low at every fixture in the house or are some fixtures good and others bad?

Did you loose the water pressure suddenly or has it been slowly getting worse over time?

What are the water pipes in your house made of; CPVC, PEX, copper, galvanized steel...?
Old 03-02-21, 02:13 PM
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Sorry I didn't get back sooner. The problem is solved but I wanted to post a reply in case someone else has the same problem.

A handyman friend came out and sawed into one of the pipes coming out of the top of the water heater. He found debris there that was blocking the flow of water. He assumes that this may have happened about 4 years ago when we had a major water leak under our driveway and they had to re-do the pipes. Right away we had good water pressure. He saved us a lot of money!

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