Ginahoy
Building Systems Engineer
A relative just did a bath remodel. His tub spout flow rate is significantly lower than with previous bath. Before the remodel, his tub fill was 7 gpm, but now it's only 4.5 gpm, so it takes much longer to fill the tub. His other bath has same setup as the bath he remodeled. He confirmed it's 7 gpm (eliminating the possibility there's a pressure issue).
The salesperson at the hardware store told him all of the mixing valves available today are more restrictive than the ones installed in his home 15 years ago, so replacing the valve with a different brand / model won't help the flow rate. Is this true? Here's a link to information on his mixing valve:
mixing_valve.pdf
One other possibility - his home has PBT pipes. Fortunately, no problems with that. But the plumber switched to 1/2" PEX under the bathroom, so there's about 6' of PEX between the transition and the mixing valve. The pex ID is 0.475" compared to 0.50" for the PBT. Surely this wouldn't cause a nearly 40% reduction in flow rate?
The salesperson at the hardware store told him all of the mixing valves available today are more restrictive than the ones installed in his home 15 years ago, so replacing the valve with a different brand / model won't help the flow rate. Is this true? Here's a link to information on his mixing valve:
mixing_valve.pdf
One other possibility - his home has PBT pipes. Fortunately, no problems with that. But the plumber switched to 1/2" PEX under the bathroom, so there's about 6' of PEX between the transition and the mixing valve. The pex ID is 0.475" compared to 0.50" for the PBT. Surely this wouldn't cause a nearly 40% reduction in flow rate?