It sounds like you have copper water lines? A long 3/4 or 1" hot line that you have to drane all the cold out before you get any hot?
It sounds like you have a 3 floors? If so I would have put a gravity recirc line in. 1/2" pex tied into your third floor hot line ran directly back to the bottum of your water heater would probaly work great. Straight pex tubes are easy to fish down through existing walls.
I always insulate my hot and recirc line, as to not run down the life of the water heater and recomend timers on recirc pumps.
I have also had good results with Grunfos hot water recirculators on existing homes. This requires no recirc line installation. You install a bypass on your farthest fixture (it is not ugly looking) and a pump on the hot outlet of your water heater. You can put aditional bypasses on for multible hot water branches as to recirc aditional fixture groups.
http://www.grundfos.com/Web/HomeUs.nsf/Webopslag/PAVA-53MKRN
I don't think eliminating turns be that noticable. Reducing the line size will give you less cold water to drain out of the hot line therefore bringing hot water quicker to the tap. Niether are solutions I would recomend.

Just a WAG but...

Somehow I've got this idea that the powder room is moving the cold water from some other lines before it takes from the WH. Is that possible with your layout? If so then maybe a check valve would shorten it down.

We put in gravity recirculation (about a 7' drop) and it only takes 4 seconds for our hot water now.

You've done time measurements, but what about flow measurement (i.e. Gallons per minute) of the hot water? I could see where the problem is some special constriction in the faucet in the hall bath such that hot water from the errant faucet (hot only) is only half the flow rate of the other faucets.

As for the 17 turns, that will reduce the water pressure and hence cause a lower flow rate. But it's only going to be about equal to the pressure drop in about 20 feet of pipe. But that still doesn't reduce the AMOUNT of water that must flow before the hot water gets there, just the pressure (and therefore the flow rate).

The other thing to check is are you sure the pipes you see in the basement are what are really feeding the hall bath? Is it possible that the pipe is going through the floor, then up to the second level, and the plumber fed the water for the hall bath from a pipe dropped down from the upstairs? The way to test this is to get two people and see how long of a time difference it is between turning on hot water, feeling hot water in the pipe as it goes through the floor, and then how long before someone in the bathroom says it's arrived. That would quickly tell if there is some "hidden" loop in the system.

Here's another far-out theory but it's based upon my own experience in my home.

If you have long runs of exposed copper pipe adjacent to heating/cooling ductwork, the temp of the water inside those pipes will be affected by what is going on in the ductwork, especially if everything is boxed in.

During the heating season, hot air is flowing through the ducts and the water in the pipes will warm up substantially, since copper is an excellent conductor of both heat and cold. During the time the air conditioning is pushing cold air through the ductwork, the hot water in the pipes will cool to the same temp if there is no water usage.

While the above might not be the total answer to your mystery, it is something for you to consider. Temperature radiation is a two-way street. Water in pipes can either give off BTU's or take BTU's on.

thanks for all your messages!

pumerrick, actually I dont have copper pipes.. they are all PVC pipes. And none of the other third floor bathrooms seem to have such a long delay. The pattern though is that everything on the right feed is ok, everything on the left is not. (Explained further below) by the way, just out of curiosity, why dont you recommend reducing the pipe size down to 1/2"?

Gary_wmy, Your idea that the pipe might be pulling the hot water from some other lines is quite plausible now that i think about it. The way the pipes are laid out, (view from the basement):

One line comes out of the WH, then it splits to go to the butlers pantry sink, the main line comes forward, does a left-right split.. the right goes to the kithchen and laundry (and two of the bathrooms on the top floor).. the left one only goes around the staircase and goes to the powder room on the main level and the hall bath directly above it. And this left split is the one that has the delay. So now, Im thinking aloud here, going by gary's thought.. is the cold water from the right split also moving into here? Shouldnt this happen when we open a tap feeding from the right split then too? Is the left right split where you are suggesting a check valve?

hookoodooku, I wanted to do this test with my husband upstairs and me downstairs as soon as I read your message. Unfortunately, as I write, we just used one of the faucets there, so hot water is instant right now.. will let it sit for a bit and then try again. You are right, we only did time measurements not flow measurements. Quick analysis there: The kitchen faucet is the largest, all the bathroom/powder room faucets are identical. (the butlers pantry is also small, laundry tub faucet is also small).

One last thought, I liked the idea of the gravity recirculator, but couldnt find any info about energy conservation and life of the water heater on their page. How does adding a recirculator affect the life of the WH. Our "expert" plumbing contractors are saying to the builder that the WH continuously keeps coming on everytime the water cools, so heating bill will go up, and the heater will be worked harder and reduce its life. Any thoughts on that?

Also, would insulating the line from the WH to the powder room sink help? Right now its just plain PVC. Insulation reminds me, the basement is all unfinished right now.. will this problem go away when we finish the basement? that is, when some insulation gets added to the ceiling of the basement around the pipes??

The reason you don't want to reduce pipe size to 1/2" is that you'll loose water pressure, especially when that pipe is carrying the load for more than one thing. That's also what causes excess hot water in the shower when someone flushes a toilet, though I don't know if that's as much of an issue with today's anti-scald faucets. But here's how it used to work:

You've got two 1/2" water lines feeding a bathroom (one hot one cold). You step into the shower and get the temperature just right. Then someone comes along and flushes the toilet. That causes more water to flow through the cold pipe. Because the size of the pipe is fixed, the speed of the water must increase to supply the extra water. But you loose water pressure via something referred to a friction losses. The concept is that the water is "rubbing" the inside of the pipe causing friction. The faster the water flows, the more pressure you loose over a given length of pipe. So when you flush the toilet, you lower the pressure in the cold water line. The amount of cold water being supplied to the shower is reduced, and the water temperature in the shower increases.

As for the idea of insulating pipes...
If you are going to do the recirculating thing, you'll want (and in some jurisdictions is required by law) to insulate the hot water pipes. That way, you'll loose less heat through the pipes and the water heater won't have to reheat that water as often.
But if you're not going to install a recirculating pump, then the only thing insulating the pipes gets you is that it takes longer for the water in the hot water pipes to cool. In reality, it just means that if someone takes a shower 5-10 minutes after you, then you don't have to wait for the hot water during the second shower. Even with insulation, it seems that my hot water in the hot water pipes only stays hot enough for 15 minutes.

Now the other thing I'm wondering about is if my initial suggestion (that the faucet is getting feed from the upstairs) is correct and was done on purpose so that to set up a recirculating system, you now just have to run pipe from that bathroom back to the water heater.

If I was your plumber and had to put more time and money into your house I would want to spend that time and money on somthing I was positive would solve your problems, make you happy and get it off my list of "things to do". Without being able to come and look at your house: the recirc, or bypass suggestions would be top on my list.

hookoodooku, thanks for the awesome explanation.. never ever thought that deeply about plumbing, and how much difference small, seemingly-inconsequential things can make.

Your thought about the recirculation is intriguing.. wonder if they really did that.
Now I have got to do that test!!!! (at least for curiosity sake).. but I need one more person ..wait for DH to come back home!

thanks plumberrick.. I think I am going to suggest bypass or recirc. to them when they come next! (They are so going to wonder where I got so much plumbing know-how!)

Mrs 0429, Did you tell us the flow rate of 'hot' water? You know that water flow rate and the time it takes to get hot will give you the length of the pipe from the hot water tank! What temperature does the hot water reach eventually?
You, of course, do have two separate faucets in your sink?
Which side is the hot faucet? (OK just kidding!!)

Cathy0429 has described her problem intelligently and deserves an explanation. I have started to think that the systems which get hot water quickly are those where hot water from the water heater has risen by convection into the pipes on the way upstairs. When a faucet is turned on, not only does she gets some hot water but the pipes are already warm and the hot water reaches its maximum temperature quickly.
I suspect that the systems which take over a minute to get hot water are those where the piping drops after leaving the water heater and since heat rises this section of pipe stays cold. 3/4 inch pvc pipe contains 2.8 gallons of water per 100 foot. Let's guess that she has 50 foot of pipe and the faucet delivers 2 gpm.
In 42 seconds, the water is warm but it still has to heat up the pipes in order for the water to reach its maximum temperature. It does eventually get to the water heater temperature, doesn't it?

To Cathy0429

Did you ever resolve your hot water issues?

I just finished installing the hot water return line for a gravity pumped recirculating hot water system to our master bath addition. It doesn't work yet, but in the meantime I have become convinced that it may waste a lot of fuel in keeping the hot water hot 24/7. Sooo, I have decided to purchase a timer controlled pump and set it to run when only when we are most likely to want it.

Now the question is, which pump? Grundfos and Laing seem to be the most heavily advertised on the web. Does anyone have any experiences with either I should know about.

Thanks for any inputs.

I had a little trouble posting this so if this is the third time you see this, mea culpa.

Rich

Rich, I opted not to go with a recirculator because of wasting energy. But when I was looking at them, I would have probably went with the "on demand" type, to save energy. These have a button you push to rapidly bring up the hot water. I have seen some that incorporate programming by time, temperature or push button, so they are pretty flexible now.

Rich

I have used a Laing pump for 15 years now.
Has outlived 2 water heaters, and one timer.
It only runs 4 hours per day, so it is not particularly stressed.
I am about to install another one for another run that
I cannot install a recirc pipe. I will have to use
their valve that pushes it back the cold water line.
I got a Laing for that also. When I was planning that
project, I sent Laing an inquiry with my plans. They were very responsive with answers to my questions.
Good customer service.

John

The kinks in your water line is likely part of the problem but not the root cause. some single handle sink and shower/tub faucets (and a few double handle)will leave the hot and cold lines connected when the faucet is turned off. This normaly causes no problem. The pressure on the two lines is equal and there is very little water movement from hot to cold in the faucet.

If your hot water line to the powder room is convoluted it can drop the pressure below the cold water pressure which is going thru the cold water line to another bath and then back thru the hot water line to the powder room. This would cause you to partialy drain both lines going to the other bath and probably you would never get really hot water, just warm.
To check this out. turn off at least one of the shut offs under all other sinks in the house. turn all shower temp control handles to full cold. Then go to your powder room and time the hot water.
If that cures your problem then you will need to install one or more check valves. Just where and how many would be determined by your plumbing layout. My preference would be to mount one on the supply lines to each offending fixture. That would leave them accessable for future service or replacement.