Drain on WH at a supply line


Ok, here's my situation. I am installing a utility sink in the basement. The house is all PEX, so there should be no problem tapping into the lines which are about 7' away. But, today I was thinking .... may be a dangerous thing. I have a propane water heater only about 8' from where the utility sink will be. What if I connected the hot water from the lower drain on the WH to supply the hot water to the sink faucet. This would accomplish "automatic" periodic WH flushing. I know the water at the bottom is not as hot as from the top, especially when it is not fired up. But, it is just a utility sink. I know in my previous houses I always tried to run a gallon or 2 of water periodically, like every month. The month turned into 2 and then maybe a year, etc. And eventually, you completely forget about it. Anyway, what do y'all think about this? Have at it.
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1. Why on earth would you "tap into" a PEX supply line... PEX is most effective when used in a home run configuration to each valve which will use water rather that using it as a replacement for copper piping the same way copper piping is used...
The whole purpose behind PEX is that it allows for a single unbroken run of tubing for each line having connections only at each end...
2. Why on earth would you connect a drain from anything your hot water heater included to feed a sink... That is utter foolishness... The lower tank drain on your hot water heater is just that, a drain, it should not be used to supply water to your home...
~~ Evan
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That may be the purpose, but that purpose assumes new construction. A home run in an existing structure can be somewhere between a royal PITA and an impossibility. I'm thinking about tapping into the plumbing in an upstairs bathroom to add a "slop sink" in a shop I'm building in the garage attic. It could be converted into a wet bar if the space is converted into a FROG (which I'll do if I move).

Now, that *is* dumb.
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Hi Art:
Can you use sludgy (sp?) water at the basement sink? My wife would not allow that. I agree it is much too easy to skip draining the water heater sludge, especially when there is always that possibility that the valve may not close fully and then you have a real problem on your hands. I am going to write myself a note right now to do our water heater tomorrow morning. It has been at least a year---------------.
Bob H
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wrote:

This comes up every now and again, and my advice is always the same... replace the cheap plastic valve with either a pipe nipple, ball valve, and MPT to garden hose thread adapter or at least a good brass boiler drain, BEFORE the thing fails. Also make sure you have a couple garden hose thread caps in your junk box in case you do have a problem. I like to leave them on the WH drains as I have ball valves, saves the floor from getting wet in case someone inadvertantly knocks the handle.
nate
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Hey Art-
Yes, a PEX installation does make the most sense (imo) on a "home run" basis and the drain port of a WH is not the best place from which to supply domestic hot water.
But......
I can also see the ease and expedience to the quick hook up you're are contemplating.
Additionally, as you mention, just by merely using the sink you'll get WH purges for "free".
Tap water can dissolve calcium carbonate into solution by virtue of carbonic acid (from CO2's slight solubility in water). Heating this tap water causes this calcium to precipitate out ..... the cause of scale forming in the WH.
The stuff is more like little pebbles / sand than "sludge".
I think your concept has merit......speed & ease of installation, plus WH sediment purges as a matter of course.
cheers Bob
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The crud from the bottom of the tank will interfere with the proper closure of most sink faucets. Run the hot form the normal supply line.
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On 6/4/2010 8:06 AM, jamesgangnc wrote:

question, I though of the problem with the filter screens in the faucet getting clogged. I don't think you'd notice the small amount of "sludge" in the water because is would happen so often in such little bits. Yesterday I purged about 1/2 gallon from the WH. It hadn't been done since moving in, in August 2009. There was a sandy look to the water. The 2nd 1/2 gallon was clear. But as I said, if it were done a little every day, you'd probably never see it. Also, the cloths washer is in another part of the house, so it doesn't enter into the picture.
As to "tapping into" PEX, my whole house is PEX and is not home run from each faucet. They did design it with a large diameter at the start of the run and going smaller at it goes to each faucet, etc. So, tapping in should be any different than it is now. The "whole purpose behind PEX" is that it is really easy and cheap to install.
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again, unless you use the old school faucets the little bits of stuff will cause the fuacets to drip. The various new style faucets do not tolerate bits of stuff gettng in them. I know, our lake house has a community well. I had to isntall a filetr trap because occsionally a tiny bit of sand would get into a fuacet. Then it dripped until I took it apart and cleaned it.
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That defeats the whole reason for using PEX...
You now have connections concealed inside the walls which are not easily accessible...
And, NO, PEX was initially developed for underfloor radiant heating applications where it was installed in unbroken loops with no connections that could fail... One end of the tubing run started at the supply manifold on the heating system and the other end of that loop was connected to the return manifold...
Someone who uses PEX as a replacement for copper pipes and runs it around to feed the whole house rather than feeding each point of use with a homerun to a manifold has totally missed the entire point behind the reason why PEX developed in the first place...
~~ Evan
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I don't disagree that the manifold installation is the best way to go with pex. But it's also popular because it is cheap, installs very quickly, if very forgiving of misaligned holes. It's hard to do a manifold installation as a retrofit. But on new construction it's a no brainer.
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Art Todesco wrote:

I had to laugh. Yeah, take hot water from drain cock.
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Art:
Most of the posters have missed your point that the tap off the water heater would be only for the new basement sink.
Bob H
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wrote:

No, most posters didn't miss the fact that it is a DUMB IDEA, no matter where the water is to be used.
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I see you've got a lot of interesting responses. Here's why I would *not* do it. The sink faucet is hot-n-cold, and the washing machine is likely nearby. Those two mixing valves will allow the possibility of a cross-connection. I mean the water is now tapped from the tank from two different points, coupled with the fact that there is a mixing valve nearby, you could get water of unknown temperature from other taps in the house. Maybe hot, maybe cold, maybe lukewarm, who knows. Water will take the path of least resistance to get wherever. By tapping into the tank in only one spot, you guarantee that it won't backfeed like that. However, I like your idea of AUTO-BLEED the sediment. If you were to hook it up somehow, I'd bet it would get used often enough so there would never be any noticeable sediment; mission accomplished.
Good Luck, Lefty
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wrote:

I've never seen "good" pressure from a HW drain. Opening the PRV lets it drain faster, but not enough for a sink faucet.
Tampering with the PRV has caused me a problem, once! It would not seal-up and leaked after that.
Tap into the PEX.
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