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plumbing curiosity

boag's picture

I am curious about a plumbing issue.

When I turn on a hot water plumbing fixture, over the first few minutes the flow decreases to nearly zero flow.

This does not happen on all fixtures on the branch line. The line is horizonal and the inlet pressure at the regulator is 105 psi - of course it drops past the regulator, but is still more that adequate.

Cold water does not exhibit this issue. All shut-off valves are open and have been cleaned and checked. All new seats and washers on the fixtures, also I did not noticethis prior to the new washers and seats.

I am curious as what could cause the decrease in flow on olny the hot side.

(post #114834, reply #1 of 20)

the heat of the water swells the cartrige/ stem or seat (or what ever you have) restricting the water flow...


good chance the HW side has the CW elements/parts in it...


 


Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming


WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!

"Some days it's just not worth chewing through the restraints"

(post #114834, reply #2 of 20)

One possibility is that you have the wrong washers in the faucets (if they use the old disk or cone shapped washers). And that the hot water causes them to swell up.

Other wise you have something in the line some place that is moving and blocking the flow of water. Had a screw head break off and fall down the pipe that did that, but it only affected that one tub.

If you have a compression or threaed stop valves you might try this. Shut off the water and remove the stop valve on the hot water that is at the end of the run. Repalce with with an adapter to a hose thread. Then put on a hose. Turn the water back on. If the problem is in the WH shut off or tank then you will still have the problem. Otherwise it will probably have fushed out whatever was in the line.

Another place that might be a problem is that some water heater have screw in heat traps. They are sorta like a check valve. And would be a good place for debrie to catch on.

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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
. William the Geezer, the sequel to Billy the Kid - Shoe

(post #114834, reply #3 of 20)

I had cone shaped washers and chaned them back to disk. Doesn't really seem to matter.

Like I said it only seems to happen since I changed the seats and washers.

I had considered expansion due to heat, or rebound in the washer. Both seemed extreme. The hot water further down the line doesn't exhibit the same problem.

Like I said in the title 'a plumbing curiosity'.

(post #114834, reply #4 of 20)

you put a cold water seat in and more than likely swapped the hot for cold and cold for hot stems...

 


Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming


WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!

"Some days it's just not worth chewing through the restraints"

(post #114834, reply #5 of 20)

"you put a cold water seat in and more than likely swapped the hot for cold and cold for hot stems..."

hot water stems are made of different material that expands/contracts less?

BruceT
BruceT

(post #114834, reply #6 of 20)

yup...

 


Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming


WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!

"Some days it's just not worth chewing through the restraints"

(post #114834, reply #8 of 20)

Use fiber washers for hot, neoprene for cold. The neoprene expands with temperature.


If your view never changes you're following the wrong leader


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

(post #114834, reply #9 of 20)

Can't switch the hot and cold stems. If you do the handle hits the shower diverter. Had these fixtures for twenty years - we are old friends and know each other quite well.


Replaced the washers with similiar materials. I'm thinking there is something with the seats - not logical but I'm limited on variables.

(post #114834, reply #10 of 20)

it's the washers and/or seats then...


are you saying the handles are fixed???


 


Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming


WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!

"Some days it's just not worth chewing through the restraints"

(post #114834, reply #11 of 20)

The cold moves counterclockwise and the hot clockwise.

(post #114834, reply #12 of 20)

100662.8 in reply to 100662.1 

Go under the sink & swap the hot & cold supplies.

(post #114834, reply #13 of 20)

no luck, it's a tub.

(post #114834, reply #15 of 20)

no luck, it's a tub.


Sorry, I thought it was a lav.


Twin handle price pfister?


Try this, shut off water, take apart hot side, take out washer, re-assemble without the washer, turn water back on, see if flow problem still exsist.

 


“The world is a dangerous place, not because of those who do evil, but because of those who look on and do nothing.”Albert Einstein

 

(post #114834, reply #7 of 20)

Go under the sink & swap the hot & cold supplies.


If the problem switched to the cold, then there is something stuck in the valve body.



“The world is a dangerous place, not because of those who do evil, but because of those who look on and do nothing.”Albert Einstein

 

(post #114834, reply #14 of 20)

You said this does not happen on all the fixtures on the branch line, is this the only tub on the line? Tub fillers are high volume, faucets are fairly low volume. Do you have a tankless coil that needs cleaning?

(post #114834, reply #16 of 20)

there are three tub on this line and four fixtures. This happens on one tub and one fixture - not in the same room.


I have an electric tankless water heater, but it does not service these rooms - and the tankless water heater is another story.


This is why this a real question mark. I redid all the fixtures (seats and washers). Two unrealted fixtures exhibit this problem. I disassembled them a second time - checked for problems (nothing obvious). Replaced the washers again with disk - from cone- and it still occurs.


I realize it is probably something micky mouse.

(post #114834, reply #17 of 20)

How does the water line run to this tub and fixture and how does that compare to the runs for the other ones?

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.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
. William the Geezer, the sequel to Billy the Kid - Shoe

(post #114834, reply #18 of 20)

You replaced the washers but you used neoprene (rubber) washers. Ya gotta use fiber washers.


If your view never changes you're following the wrong leader


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

(post #114834, reply #19 of 20)

The hot and cold run the full length as a main. Laterals come off to supply each of the fixtures/tubs.


I will try the seat and fiber washers this afternoon, and report back.

(post #114834, reply #20 of 20)

The problem is fixed.

Took the stem out and flushed the line. Got out some pieces of rubber. Didn't expect this, but I had the same problem I fixed in another part of the house (different line -rubber bit in the shut-off valve).

I replaced the shutoff vales with ball valves - no gaskets some time ago. I can only believe that it came from outside.

Thanks for the help.