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Iggier 03-27-2010 11:06 AM

Pressure Loss Using Two Fixtures at Same Time
 
In my multi-level townhome, I cannot use two sources of water at the same without a significant loss of pressure (or maybe it's flow??) to the other. For instance, if running the dishwasher, the shower, other faucets, toilets, etc. will experience markedly reduced pressure. If I flush a toilet, the kitchen faucet, for example, will slow to a trickle.

One plumber checked the meter at the street and found nothing out of the ordinary. He suggested it was a municipal volume issue. However, immediate neighbors do not have the problem described above. Another plumber said that more often than not, a faulty PRV is to blame. His minor adjustment to the PRV made no difference, and he recommended replacement.

What would the experts on this forum surmise?

Akpsdvan 03-27-2010 12:01 PM

Quote:

Originally Posted by Iggier (Post 420367)
In my multi-level townhome, I cannot use two sources of water at the same without a significant loss of pressure (or maybe it's flow??) to the other. For instance, if running the dishwasher, the shower, other faucets, toilets, etc. will experience markedly reduced pressure. If I flush a toilet, the kitchen faucet, for example, will slow to a trickle.

One plumber checked the meter at the street and found nothing out of the ordinary. He suggested it was a municipal volume issue. However, immediate neighbors do not have the problem described above. Another plumber said that more often than not, a faulty PRV is to blame. His minor adjustment to the PRV made no difference, and he recommended replacement.

What would the experts on this forum surmise?

One idea might be to put a Pressure Gauge in to the line just after it comes into the house from the street.
Once that is in place .. have some one watch that gauge and go and open on fixture and note the pressure change, then open another fixture and note that change with 2 fixtures using water... if the gauge does not change much then there is a block some place in the house, if it changes then the city is not giving, feeding you the water at a pressure that is right..

Just a thought...

AllanJ 03-28-2010 07:43 AM

How old is the house?

Older homes or homes with steel or iron piping may suffer from arteriosclerosis where the most practical cure is, unfortunately, replacing the affected pipes.

I have seen pictures of pipes where the remaining passageway for the water was down to about an eighth of an inch in diameter.

majakdragon 03-28-2010 08:57 AM

I agree with using a pressure gauge to find out what the normal pressure is and what happens when another fixture is turned on. It could be that the main feed line in the house is too small. I always use at least 3/4" for the main run and tee off with 1/2" to each fixture. The pressure reducing valve may also be bad. This does happen.

Iggier 03-28-2010 06:40 PM

Quote:

Originally Posted by AllanJ (Post 420685)
How old is the house?

15 years, built in 1996.

The home, by the way, is relatively new to me. I can't believe the prior owners didn't have this problem (and that they failed to disclose it on the sales contract - but that's another issue entirely).

Akpsdvan 03-28-2010 07:43 PM

Quote:

Originally Posted by Iggier (Post 420925)
15 years, built in 1996.

The home, by the way, is relatively new to me. I can't believe the prior owners didn't have this problem (and that they failed to disclose it on the sales contract - but that's another issue entirely).

Did this pressure deal just show up or has it been working at getting worse?

Iggier 03-28-2010 08:29 PM

Quote:

Originally Posted by Akpsdvan (Post 420955)
Did this pressure deal just show up or has it been working at getting worse?

I noticed the pressure problem when I first moved into the house about a year ago. It's only logical that the prior owners were aware of it as well. Has not worsened.

Akpsdvan 03-28-2010 08:56 PM

Quote:

Originally Posted by Iggier (Post 420978)
I noticed the pressure problem when I first moved into the house about a year ago. It's only logical that the prior owners were aware of it as well. Has not worsened.

I can go along with that....

So there is either a supply challenge from the city, or there is some kind of build up in the lines in the house...

The screens at the facets... new or old?

slickgt1 04-01-2010 03:20 PM

Quote:

Originally Posted by Akpsdvan (Post 420996)
I can go along with that....

So there is either a supply challenge from the city, or there is some kind of build up in the lines in the house...

The screens at the facets... new or old?

How would screens at the faucets affect his problem? I am just curious as I have heard this before. thanks.

Piedmont 04-01-2010 03:39 PM

The times I've seen this are:

1.) The city pressure is ginormous and a pressure reducer was installed to lower it and it's faulty, gunked, or wrong spec.

2.) There's a broken or partially closed valve. First make sure all water supply valves are fully open. It will be hard to tell if there's any broken gate valves (their symptom is usually you can't close & seal them tight). Not too hard to find partially closed valves with a PEX manifold system.

3.) If you have a tankless system, they have a flow restrictor to make sure you don't draw more than it can handle. For example, if it can only heat 3 GPM it will only allow 3 GPM. 2 people using hot water at the same time each will get 1.5GPM however only the hot water would be affected.

4.) Heating systems especially forced hot water baseboards have a pressure reducer to reduce pressure in the heating system to around 12-15 psi. It could be possible an idiot attached your main water supply to the heating system supply after the pressure reducer. Needs to be before.

5.) Does the house have a water filtration system? That could sap a lot of pressure.

This is PEX right?

Akpsdvan 04-01-2010 07:47 PM

Quote:

Originally Posted by slickgt1 (Post 422770)
How would screens at the faucets affect his problem? I am just curious as I have heard this before. thanks.

I should be taking some photos the next time, a photo is worth a 1000 words..
In short think of the screen/aerator as a flow control .
It is like the screen for either the front or back doors of your house, if the screen is clean air flows with no problem, but if that screen is covered in dirt and dust then the air will have a harder time passing from one side to the other..

The other day the water flow at this one place was next to nothing.. took that screen/aerator off and the part that would be the first to see water had this large and I mean large ball like pile of Iron.... cleaned that up and water flow was better ... other things still needed to be done to the iron removal system to get full pressure and flow back but that was one of the many challenges for this one place.

slickgt1 04-02-2010 09:09 AM

Quote:

Originally Posted by Akpsdvan (Post 422884)
I should be taking some photos the next time, a photo is worth a 1000 words..
In short think of the screen/aerator as a flow control .
It is like the screen for either the front or back doors of your house, if the screen is clean air flows with no problem, but if that screen is covered in dirt and dust then the air will have a harder time passing from one side to the other..

The other day the water flow at this one place was next to nothing.. took that screen/aerator off and the part that would be the first to see water had this large and I mean large ball like pile of Iron.... cleaned that up and water flow was better ... other things still needed to be done to the iron removal system to get full pressure and flow back but that was one of the many challenges for this one place.

Wow. I am building a house now, and this neighbour keeps nagging me to check his situation as well. My plumber went back to Russia, so I took a quick look myself. The water hot, and cold trickles. I guess I can check the screens too. I just don't want to touch any of his 100YO piping and have another giant job on my hands.

Sorry for jacking your thread Iggier, but we are on the same subject here, so I hope you don't mind. Thanks.

Iggier 04-02-2010 09:56 AM

Quote:

Originally Posted by Piedmont (Post 422784)
The times I've seen this are:

1.) The city pressure is ginormous and a pressure reducer was installed to lower it and it's faulty, gunked, or wrong spec.

I think this is most likely based on a quick evaluation when plumbers recently installed a new hot water heater.

Quote:

2.) There's a broken or partially closed valve. First make sure all water supply valves are fully open. It will be hard to tell if there's any broken gate valves (their symptom is usually you can't close & seal them tight). Not too hard to find partially closed valves with a PEX manifold system.
I'll leave this to a plumber.

Quote:

3.) If you have a tankless system, they have a flow restrictor to make sure you don't draw more than it can handle. For example, if it can only heat 3 GPM it will only allow 3 GPM. 2 people using hot water at the same time each will get 1.5GPM however only the hot water would be affected.
Not a tankless system.

Quote:

4.) Heating systems especially forced hot water baseboards have a pressure reducer to reduce pressure in the heating system to around 12-15 psi. It could be possible an idiot attached your main water supply to the heating system supply after the pressure reducer. Needs to be before.
Main pipe from street comes directly into home and splits into two branches, one a fire sprinkler system and the other house water. Each has a separate on/off valve. A PRV sits immediately after the house branch but before the house on/off valve. There is no evidence that main supply is attached to the heating system.

Quote:

5.) Does the house have a water filtration system? That could sap a lot of pressure.
Nope!

Quote:

This is PEX right?
Doesn't appear to be. Just standard copper with the usual fittings.

Thanks for all the advice - it's been very helpful. I'm trying to narrow down the possibilities before I spend huge $$ for a plumber to investigate this.

Iggier 04-04-2010 11:40 AM

Did some testing today with a water pressure gauge and here are my findings:

Front of house hose bib = 82 psi
Flushing a toilet on the same level drops pressure to 22 psi
This is for supply line water connected to the pressure reducing valve.

Pressure at fire sprinkler valve = 91 psi
Flushing toilet, no change, pressure remains at 91 psi
However, the sprinkler water delivery (pipe) bypasses the pressure reducing value, although it is connected to a backflow preventer. Because there was no drop in pressure at this point when flushing the toilet, the backflow preventer is working as it should.

Pressure inside the home should be about 65 psi constant. Because pressure measured at the hose bib is 82 psi, where it should be 65 psi, the likely culprit is the pressure reducing valve.

It's several hundred dollars to replace the PRV. Before I arrange the work with my plumber, I'd like to know if others agree with my findings.

Thanks.

Akpsdvan 04-04-2010 01:30 PM

Quote:

Originally Posted by Iggier (Post 423930)
Did some testing today with a water pressure gauge and here are my findings:

Front of house hose bib = 82 psi
Flushing a toilet on the same level drops pressure to 22 psi
This is for supply line water connected to the pressure reducing valve.

Pressure at fire sprinkler valve = 91 psi
Flushing toilet, no change, pressure remains at 91 psi
However, the sprinkler water delivery (pipe) bypasses the pressure reducing value, although it is connected to a backflow preventer. Because there was no drop in pressure at this point when flushing the toilet, the backflow preventer is working as it should.

Pressure inside the home should be about 65 psi constant. Because pressure measured at the hose bib is 82 psi, where it should be 65 psi, the likely culprit is the pressure reducing valve.

It's several hundred dollars to replace the PRV. Before I arrange the work with my plumber, I'd like to know if others agree with my findings.

Thanks.

The Idea sounds sound.. if that valve is not opening up enough to let the water flow to inside the house it would cause the drop in pressure and flow.
Check and see if there is a repair kit for the PRV.. or if there is a way of cleaning it out.


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