1

I've seen variations on this question, but the only times I've seen this exact question, the answers haven't been helpful... so thought I'd try here.

I've got a 66 gal. electric hot water tank, 10-15 years old, that feeds 3 full baths and a kitchen. One bath is in the finished basement, everything else is on the ground floor.

Get reasonably good hot water pressure / flow to every faucet / tub / shower EXCEPT the sink in the master bath. Have replaced everything back to the iron supply stub coming out of the wall, problem seems to be getting worse. Hooking a line directly to first the hot, then the cold supply stubs confirms that what's coming out of the wall is way weaker for the hot than the cold.

I'm thinking sediment (rust / calcium / ???) in these older pipes, probably at an elbow or tee... and that all my shutting off, turning on, attempting to flush that line have just caused more crap to move downstream to add to the blockage.

Is this the most likely cause?

If so... is there any trick I can use to break up or dissolve this unknown upstream blockage without tearing into the finished basement to try and hunt down the affected pipe?

4
  • Hello, and welcome to Home Improvement. Interesting question, and good sleuthing; let's see if one of our experts can suggest something. Mar 4, 2019 at 2:43
  • 1
    If all efforts to clear the blockage fail I'd be looking at abandoning the existing pipe rather than locating and repairing it. Depending on the orientation of floor joists, air duct chases, etc there might be a way to route a new PEX tube with a minimum of access points cut through the wall coverings. A USD$20 USB bore scope camera may be valuable for assessing this possibility.
    – Greg Hill
    Mar 5, 2019 at 4:01
  • Is it possible the shower control has an anti scald set up which is further restricting the hot and mixing it with cold at the tap? If so, you could turn this up to let more hot in…
    – mark f
    Jul 17, 2022 at 16:22
  • You state " iron supply stub" if that is an indication of how your house is plumbed you are in for a lot of problems in the near future. My guess is the house was built maybe in the 60's or before. Iron pipes "calcify" and the inside slowly gets smaller. The only true fix it to replace them. If you are planning on remodeling add plumbing to your todo list. Be careful "banging" on pipes could dislodge more and cause further blockages. You were specific about the hot, if it were hot and cold I would suggest cleaning the aerator in the faucet.
    – Gil
    Nov 14, 2022 at 18:14

2 Answers 2

0

If it is sediment, you could open only that problematic hot water tap at the sink, then shut off your water supply to the house and drain your water heater. That will suck all the hot water back down the line in the other direction and maybe flush out what is in there. that will at least be a way to narrow down if it is sediment within the line.

1
  • 1
    Could even go a step further and back-flush the hot supply line. Shunt cold to hot at that master bath sink, open the hot line "upstream" at the heater or other suitable place where the water and potential debris can be drained out, and let pressurized cold water flush backward through the hot piping.
    – Greg Hill
    Mar 5, 2019 at 3:57
0

Sounds like galvanized pipe, this is a big problem. If you loosen the build up it can make leaks.

1
  • 1
    Hello, and welcome to Home Improvement. Interesting idea; why do you think so? (A bit more info in your answers would be helpful.) Thanks. Mar 5, 2019 at 10:52

Not the answer you're looking for? Browse other questions tagged or ask your own question.