Water taking forever to heat up

[TrudgingAlong]

I'm baffled as to what is causing this situation. The kitchen water takes FOREVER to heat up. Like, I can turn it on, go slice some vegetables, and it's still running cold. We moved in in Feb, so I blamed the winter, but it's warming up now and the time it takes to warm up versus the downstairs bathroom (not far from the kitchen at all) is very noticeable. Ideas?

[sokoloff]

Does it eventually get fully hot? If not, and you have a single-lever faucet, suspect that the valve may be bad. Has someone added a recirculation valve/pump that might be bad?

To troubleshoot that, you could disconnect the hot supply at the shutoff under the kitchen sink, remove the hot line feeding the faucet and run a temporary line into a bucket. Turn the shutoff back on and if that gets hot as quickly as you'd expect, you've confirmed the problem is in the kitchen faucet.

For other ideas, we'll need to know (or you'll need to think about) how your house is laid out. Is the kitchen far from the water heater? Is there a mixing valve plumbed into the line supplying the kitchen? Does the hot line run through uninsulated space? Is the hot line excessively large or long (40' of 3/4" copper pipe holds a gallon of water; 1/2" copper holds about half that.)?

[sokoloff]

Or perhaps a simpler test:
Turn the kitchen faucet full hot on the kitchen sink and let it run.
Turn off the cold shutoff valve under the kitchen sink.
Did anything change about the flow in the kitchen sink?
Leaving it shut off, does the water now heat up faster?

Anytime you move an old shutoff valve, you risk a leak. It's just the way of the world, so be sure to keep an eye on the valves for a couple days after your experiments/work. I don't want you to be slowly dripping water into your cabinet unnoticed.

[TrudgingAlong]

Thank you! I will give this test a try. We do have a single faucet, and I sort of wondered if that was part of the problem. There is also a pipe that runs through the crawl space that our home inspector had highlighted because it was uninsulated. We asked that to be fixed before we moved in, but haven't actually crawled under there to see if they did so (or how it was done!). Not sure if that is a line to the kitchen, though. Our water heater is in the garage, maybe 12 feet from where the sink in the kitchen is, so this has really been odd to me. The dishwasher seems to get hot, and we do get hot water eventually in the sink.

[Salvo]

You could also try raising the temp on the water heater itself. 

[geekette]

You may have an unfortunately long run from the water heater to the kitchen sink, and the other sink has a shorter run.

We had our house replumbed years ago, and it was interesting to see how the lines ran. It wasn't point to point like an electrical circuit; most ran fairly separately.

[Spork]

Thank you! I will give this test a try. We do have a single faucet, and I sort of wondered if that was part of the problem. There is also a pipe that runs through the crawl space that our home inspector had highlighted because it was uninsulated. We asked that to be fixed before we moved in, but haven't actually crawled under there to see if they did so (or how it was done!). Not sure if that is a line to the kitchen, though. Our water heater is in the garage, maybe 12 feet from where the sink in the kitchen is, so this has really been odd to me. The dishwasher seems to get hot, and we do get hot water eventually in the sink.

Just a side note:  12 feet in physical distance doesn't necessarily mean 12 feet of pipe.  Depending on how it was designed/built/remodeled/re-remodeled/etc.  ... water could run around the house 3 times before it gets to your sink.  Probably not... but I've seen dumber things.  If you have a crawl space, it might be worth a trek into the ick to see. 

[TrudgingAlong]

Yep, think we'll have to venture into the crawl space. The valve seems fine, per the shutoff test suggested above.

[sokoloff]

Yep, think we'll have to venture into the crawl space. The valve seems fine, per the shutoff test suggested above.

Meaning that with the cold supply shutoff that the water eventually gets full hot, but takes a while?

[BTDretire]

 Years ago I did a non-mustachian thing by installing a recirculating pipe to my kitchen sink.
The water heater was in the basement and hot water flowed naturally up the pipe to the sink, or was it the cold water that sunk back down to the heater. But anyway, instant hot water, no running a gallon of water to get to the hot water.