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schultz56 02-16-2010 08:44 AM

Suggestions on adding an on-demand water heater
I have a 3 bedroom home, about 1800sf, with 1 1/2 bath. Only 1 shower/tub. The problem I am having is that I seem to run out of hot water after just one shower. I just installed a new 50 gallon hot water tank not even a year ago. I was wondering if adding an on demand hot water heater would help. I was thinking of doing this just for feeding the shower/tub. Do I feed this new water heater with the hot line or cold line?

Or could the problem be in the mixing valve in the shower? After a shower there seems to be no hot water even at the lav.

user1007 02-16-2010 12:47 PM

I had a 3,000 sf Northern California ranch house that drove me nuts. The water heater was 800 miles away from the showers and stuck in the garage and it seemed like you really did have to turn the hot water on at 4 in the morning if you wanted a 6 am hot shower with water flowing through the lines at 8-10gpm. And then like you, I would get one 15 minute shower wasting all that lukewarm water in the meantime. My other issue was that water was so hard tank heaters would cake up and have to be replaced every two or three years, even if you bled them out regularly. They worked fine, there was just too much cold water stuck in the pipe runs that had to get out of the way before the hot water reached the baths.

I finally went tankless/on demand and bought high end Bosch units (about all available at the time). I stuck a big one in for the two baths at their end of the house and a smaller one for the kitchen at the other end. Loved it! They were expensive but I never had any complaints about waiting for or having enough hot water in the morning anymore. Since they were not storing water, I didn't have to replace them while I was still living there!

They saved a noticeable amount of energy. Northern California, one of the suppliers of water to Southern California, was subject to water rationing. SC never has been. Go figure; Hollywood glams got to have full swimming pools and washed luxury cars I guess. The water savings in quantity used was significant.

Have always loved the little tiny things in Irish B&Bs too. Turn them on for a few minutes and you have more than enough hot water for a luxurious shower.

I convert people to on demand water heaters all the time now. No real complaints other than some of the cheaper units don't seem to hold up so well. Still beats the concept of boiling water way out at the extremities of a house and piping it miles through a cold basement though?

vsheetz 02-16-2010 09:27 PM

I have a large Bosch tankless water heater - endless hot water, it's great... When I add a new master suite in a couple years at the far end of the house I will put one there as well.

Alan 02-16-2010 09:43 PM

If you're running out of hot water after 1 shower, then you have either :

A) someone is taking a really long shower

B) something is wrong with your elements and/or thermostats

C) electrical issue

D) some kind of leak in the hot water line, either OUT, or a crossover where cold is feeding into the hot as you're using it.

You DO NOT NEED to add an on demand for that size house with that size of heater.

SULTINI 02-18-2010 06:41 AM

I agree

I liked the way you layed that out Alan I would check all of the outlined issues before moving on the purchase.

50 GAl a lot of hot.

schultz56 02-18-2010 08:05 AM

The shower time is not too long, probably about 15 min max.
Tank is gas fired not electrical.
How would I check the t-stat make sure it is working properly?
Where would the "crossover" problem be happening?
I have the old style 3 valve shower/tub faucet. hot, cold and the diverter valve.
Also when I notice that the hot water is running out in the shower I barely have the cold on at all.

Alan 02-18-2010 09:25 AM

As far as checking the T-stat, how electrically inclined are you ? This requires a fair bit of common sense and knowledge of how to use a multi-meter.

Crossover could be happening at some other faucet in the house. What other types of faucets do you have? Try turning off the undersink valves on the HOT SIDE to all of your faucets when you take a shower and see if the problem goes away.

schultz56 02-18-2010 09:29 AM

Pretty electrically inclined. I have a sink in bath with shower, sink in powder room and Kitchen sink. Luandry tub in basement. How would turning of hot water valve under sink help?

Alan 02-19-2010 09:03 AM


Originally Posted by schultz56 (Post 402005)
Pretty electrically inclined. I have a sink in bath with shower, sink in powder room and Kitchen sink. Luandry tub in basement. How would turning of hot water valve under sink help?

It would prevent cold from entering into the hot side of the system through the faucet that may or may not be in question. This is an easy and safe test. :yes:

Mike in Arkansas 02-19-2010 09:14 AM

If this is a Whirlpool water heater, they sold some with defective valves. I had one and had the same issue as you do, very little hot water. If it is a Whirlpool you can call them and they will replace the valve as it's a known issue.

schultz56 02-19-2010 09:51 AM

It is in fact a whirlpool! Do you have a complaint number associated with this issue or anything? Or did you just contact whirlpool and tell them your issue? Which valve?

Mike in Arkansas 02-19-2010 11:27 AM is a link to where I found out about the problem just a few days ago. Go down several postings. Got my replacement at Lowes. Don't have a valve number right now but it's square on the face, about 1 to 1.5 inches deep with the attachment pipe coming out the back side. You might try posting to that link, maybe the person who told me has additional info he can provide.
Okay, the number on my valve is 64-LF8-376 R110 RATSPL
If you find out more, please post here. I might see if I can get reimbursed for the valve cost.

Alan 02-19-2010 11:02 PM

You have a... gas water heater? :whistling2:

SULTINI 02-20-2010 06:52 AM

It appears this is getting confusing, let's keep this simple go back from the beginning and start over and ask yourself a few questions.

Gas or Electric??

What Valve?.

Brand name?

Troubleshooting did you try what was asked already?

Shut off the cold water and run the hot only to the shower, time it while it's running look at your HWH to see if it's fired up or if the elements are heating. Check the temp of the water during test. 50 GAL alot of Hot.

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