Hot water tank plumbing question / low hot water pressure

[ClydesdaleKevin]

Sent: 5/30/2005 10:11 PM

The heater is a newer Atwood model that some P/O put in.  After chasing down every leak in my plumbing, I finally got to the point where I was fine tuning things...and noticed that my hot water pressure is about half that of my cold water pressure.  Is this normal?  I haven't filled my propane tanks yet to test the propane system, but is the water hot enough that it is designed with lower pressure than the cold water?

it seems to me that there is a missing valve.  There are only two on this unit, and the lower inlet valve seems to me to be the problem. 

The lower valve, is on the inside of a T fitting, close to the tank.  When open, it doesn't shut off the water supply to the water pipe that goes past the tank...I still need to trace that line and see if its a bypass, or a hard line that supplies cold water to the sink. 

Anyway, is significantly lower hot water pressure normal because of the small size of our hot water tanks, or do I have a problem that needs to be fixed?  If I need to fix it, any of you have any pictures of the way yours is plumbed, or better yet a diagram I can follow?  I was an electrician in the Navy, not a plumber...lol.

Kev

[W0X0F]

Sent: 5/30/2005 10:54 PM

Kev,

That set up looks like a bypass valve set up, normally the handles will point the way the water will flow. You may have some blockage in the pipes. Hope this helps you somewhat.

[mightybooboo]

Sent: 5/30/2005 11:22 PM

My hot flows as fast as the cold water does.

BooBoo

[salplmb]

Sent: 5/31/2005 12:36 AM

the valves you have look like a bypass set up. from what i can see it looks like the inlet piping (cold) is smaller than the outlet piping (hot). if so there will be a drop in preasure on the hot side due to the fact that the water can run out of the tank faster than the smaller diameter pipe can fill the the tank to the proper preasure. this can be fixed by increasing the inlet pipe size or resticting the flow out of the heater.is the copper line going between the two valves? that would indicate a bypass and you should be able to turn the valves to isolate the tank. this should also bring the preasure on the hot side back up some because the tank no longer has to fill before reaching full preasure. if turning the valves dose nothing but shut off the hot water then i would look at the valves for some type of restriction. in a proper sized system both sides will have the same preasure and volume of water. sorry for the long post. hope this helps a little.
sal

[OldEdBrady]

Sent: 5/31/2005 9:01 AM

Wter pressure should be equal, cold or hot.  Sounds like you have the problem narrowed down on the bypass valves.  There should be two, one at the bottom of the tank, and one at the top.  They should also be connected together with a small length of hose.

When both are open to the tank, hot water is available.  When both are closed, only cold water should be available from both the hot and cold taps.

The bypass valves in the Whiny Beggar are both brass, and I KNOW they are a bit worn, because, even shut off, a tiny amount of hot water still comes through.  But it hasn't been a problem, since I rarely use the bypass hose, and it's something I can put off replacing until I've taken care of hundreds of more pressing problems.

I had another thought about this.  What about possibly a blocked hot water line?  I'd check it first, since it's cheapest to replace.  Where the line comes out at the top of the tank, take the line off.  Open one of the hot water taps and just blow through it.

If there's no real resistance, then there's no blockage, so I would suspect the bypass valves (at least one of them).  Again, while you have the water line off, the top valve is easiest to check out.  Take it out.  They're might small, and, if it's blocked/worn, you should be able to see that simply by working the valve back and forth.  You can always check the lower one later, if the top one is fine.

When you put it back together, don't forget to use telfon tape or pipe compound to reseal it!

[ClydesdaleKevin]

Sent: 6/20/2005 4:21 PM

Problem solved!  Before we left, I removed all the bypass valves and whatnot.  I used new fittings and plumbed it all directly.  Perfect water pressure now from both cold AND hot! 

These little propane Atwood hot water heaters are amazing, by the way!  I can't dilly dally in the shower, but I can take a normal unrushed 5 minute shower, including washing my hair, without running out of hot water!  The recovery rate is pretty incredible as well!  If I do run out of hot water, its hot again in less than 10 minutes!  I don't know how efficient they are propane-wise, but they sure work well!

Kev