I have new PEX plumbing running through the attic in a 1BR/1BA guesthouse with 3/4” supply running ~20-25 feet to the WH and then to a manifold that branches water out with 1/2” PEX.
I have the incoming water pressure set to 65 PSI (have also increased it), but the issue I’m seeing is low flow almost immediately.
I can watch the water pressure drop from 65 to 0, then it will build back up once the fixture is closed.
The kitchen and bathroom sinks run decent enough to make use of, but the shower is basically useless. The toilet is useable but obviously fills slower than it should.
I’ve eliminated the incoming check valve+PCV by running direct feed of ~85psi; all the PEX appears leak free in attic; and the WH has also been bypassed.
I’ve tried isolating every fixture except one for all fixtures except the washer and the fridge water (neither turned on yet), but flow is always lower than it should be.
I think the only things I haven’t eliminated are possible routing issues in attic (runs are pretty straightforward), the thermostatic valve for the shower, or the main manifold itself...but all the valves on that seem to operate fine and I can clearly hear lines charging when I actuate them.
Throwing it out there for any thoughts anyone may have. One other note that may be nonstandard is the incoming supply feeds the toilet with cold water before it goes to the WH. The toilet wall was closest so didn’t see the point in running water back to it through the manifold ~20’ further down. Not sure if this would cause a drop in flow even when the toilet isn’t in use though.
There is one cold run to the outside of the house branched off of that is also 3/4”, along with a hot water 1/2” line for an outdoor shower.
If I attach a gauge to the cold and run the hot without a fixture (valved line), then I can watch the pressure drop off on the cold to zero in less than 10 seconds). I’m sure the same would be true vice versa.
The pressure drop off isn’t that quick inside and the only place that is completely shot is the shower, so I’m thinking my fancy thermostatic valve from Ferguson’s May have an issue...not sure that would impact everything though.
I have the incoming water pressure set to 65 PSI (have also increased it), but the issue I’m seeing is low flow almost immediately.
I can watch the water pressure drop from 65 to 0, then it will build back up once the fixture is closed.
The kitchen and bathroom sinks run decent enough to make use of, but the shower is basically useless. The toilet is useable but obviously fills slower than it should.
I’ve eliminated the incoming check valve+PCV by running direct feed of ~85psi; all the PEX appears leak free in attic; and the WH has also been bypassed.
I’ve tried isolating every fixture except one for all fixtures except the washer and the fridge water (neither turned on yet), but flow is always lower than it should be.
I think the only things I haven’t eliminated are possible routing issues in attic (runs are pretty straightforward), the thermostatic valve for the shower, or the main manifold itself...but all the valves on that seem to operate fine and I can clearly hear lines charging when I actuate them.
Throwing it out there for any thoughts anyone may have. One other note that may be nonstandard is the incoming supply feeds the toilet with cold water before it goes to the WH. The toilet wall was closest so didn’t see the point in running water back to it through the manifold ~20’ further down. Not sure if this would cause a drop in flow even when the toilet isn’t in use though.
There is one cold run to the outside of the house branched off of that is also 3/4”, along with a hot water 1/2” line for an outdoor shower.
If I attach a gauge to the cold and run the hot without a fixture (valved line), then I can watch the pressure drop off on the cold to zero in less than 10 seconds). I’m sure the same would be true vice versa.
The pressure drop off isn’t that quick inside and the only place that is completely shot is the shower, so I’m thinking my fancy thermostatic valve from Ferguson’s May have an issue...not sure that would impact everything though.
