Low pressure on hot water recirculating system.


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Old 12-31-09, 11:05 AM
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Low pressure on hot water recirculating system.

The pressure on my hot water varies considerably. Sometimes when running the bath water is is as low as a dribble to a low, but acceptable pressure. Why would the pressure vary and why would there be less than a normal pressure?
 
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Old 12-31-09, 03:31 PM
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I'm going to assume that when you wrote pressure you meant to write volume, as in the amount of water coming from the faucet is less than it once was.

Why did you write about recirculation in the title? Do you have a system that recirculates the cooled hot water back to the heater so as to always have almost instant hot water when you open the faucet?

Do you have aerators on the affected faucets? If yes, have you attempted to clean them? Do you perhaps have galvanized steel piping rather than copper?
 
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Old 12-31-09, 06:48 PM
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And you mention that this is the hot water having the problem. Does the cold have the same problem?

There's nothing in a recirculating system that is going to cause the pressure to vary.
 
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Old 12-31-09, 07:49 PM
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The pressure/volume (as I should correctly have said) is normal for the cold water. I mentioned the recirculation system which circulates the hot water so that we have instant hot water since this is the only difference between the delivery of the cold water and the hot water. The reduced volume is common to all faucets. The initial pressure and volume is normal and then the volume drops off in less than a minute.
 
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Old 12-31-09, 08:03 PM
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I would guess that the problem is at the WH rather than with the recirc. system. If there are heat trap nipples on the top of the WH and one or the other is malfunctioning, that would cause the problem that you are describing. That would be more likely than anything to do with the recirc. system.
 
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Old 12-31-09, 08:32 PM
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I would tend to agree with you re the circ system not being the problem. Since everything seemed normal and not knowing anything about the circulating system my first thought that the problem must lie with that system. I looked at the piping and could not see anything th at looked like it would create a problem; however. If the chances are the the problem does not lie with this system I will start with the H/W heater and go from there. My house is only 5 years old and the plumbing is mostly plastic so there wouldn't be a corrosion problem.
 
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Old 12-31-09, 09:25 PM
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Hey neighbor!! (I'm about 3 miles west of Smokey Point)

5 years old -- corrosion isn't a problem. Plumbing is mostly plastic -- do you mean PEX??

That could be another source of the problem if the main hot line has a bend in it the is collapsing. PEX is done with manifolds. If the main line off of the WH is collapsing at the hot manifold (or someplace between the WH and that manifold), that would also cause the problem you are talking about.

It's probably something a plumber needs to look at if you can't figure it out on your own.
 
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Old 01-01-10, 08:00 AM
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I'm not used to the terms, but it is the soft plastic that they expand to make the joints. I was an apprentice plumber about 50 years ago, but pipe types and codes have changed considerably since then. If you talk durham, cast iron, galvanized, caulking, etc. I'm in the ball park. Copper was just coming into play.

I noticed we were neighbors. As the crow flies just a few miles.
 
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Old 01-01-10, 01:07 PM
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I had a slight kink in a flex copper tube coming into the HW Heater so I replaced that. That didn't resolve the problem so I thought it might be the HW heater. I decided to check the water going into the HW heater first. That had no volume so I checked the next thing up line which was the check valve. I found that the flapper on that was completely off. I was sure I had the problem resolved, but that didn't do it. The next thing up line is the gate valve. What are the chances of that not opening fully? If it is not that it is going to take tearing out insulation to find the connections on it. NOT FUN!!
 
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Old 01-01-10, 02:45 PM
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The gate valve not opening fully or the gate having become detached from the stem is a very real possibility. If you find that to be the problem I would suggest replacing the gate valve with a ball valve.

By the way, I'm in Bothell, just north of the King/Snohomish county line so we are all neighbors.

Lefty, did you get lonesome for our liquid sunshine or just get tired of all the bright sunshine of California?
 
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Old 01-01-10, 06:02 PM
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It looks like the problem may be with the gate valve. I tried to replace it, but couldn't get it off due to too much water still being in the line. I took it apart and adjusted the valve and the volume seems pretty good. The problem now is with leaks when I replaced the check valve. I had problems getting rid of all the moisture so am going to leave it until morning and then give it more time to get it completely dry. I did get the solder to take, but there must have been enough moisture to not get a good joint.

BTW: I spent my teen age years in Clearview. We lived accross from the Bits and Spurs riding field.
 
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Old 01-04-10, 01:28 PM
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The more I thought about it the more I realized the problem couldn't be with the gate valve since the gate wasn't loose. I was led to believe that it was the gate valve because it improved after I took it apart, but it didn't make sense. My doubts were confirmed when the volume eventually decreased. To test the gate valve I took the gate off and put the remains back together. The volume did not increase so I put the gate valve back together. My next test is to route around the hot water heater. Spouse says she needs to do wash so that is delayed. If it isn't the HW heater I have eliminated everything from the gate valve through the HW heater. Since this is the new plastic piping system I assume there must be a manifold system. I highly doubt that there would be a problem between the manifold and gate valve since the plastic pipe is fairly thick and not likely bent. I doubt that a bent pipe would be the problem since the volume varies between different times of using the tub from a trickle to an acceptable amount. This leads me to believe that something is plugging it somewhere, but where??
 
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Old 01-04-10, 03:38 PM
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Update:
I checked the water going into the hot water heater with a hose and the water going out from the HW heater with a hose both had adequate volume. The problem has to be with somewhere from the HW heater and the first terminal from the HW heater since the lack of volume is affecting all the faucets. I was so focused on the Circ system since I did not understand it. Once I got a grasp on it I assumed it was the check valve. When I found a problem with that I thought I was home free. When that didn't work I looked at the gate valve. When it worked after checking it out (and finding no problem) I figured it had something to do with that. Never did it come to mind that it would be in the piping after the HW heater. My last test should have been the first and I would have saved a lot of work. Got to be a lesson there somewhere!!!
 
 

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