hot water pressure is 57% less than cold on new water heater

wdgates

new replacement water heater has less pressure, could I have a faulty water heater? I checked GPM at 3/4 discharge hot 6.16 & cold 10.68 at the tub faucet hot 2.8 cold 4.8. After the new install, if any hot water faucet is turned on the shower goes cold. Did not have this issue with the original water heater, is this a bad unit?

joecaption

Hmm, very little info. no pictures.
What other plumbing did they do when installing it?
Where are you checking the flow.
100% sure the valves are fully open that someone had to shut off to change the heater.
What type valves are they?
Why was the heater changed?

wdgates

I replaced a bradford white direct vent (22yrs installed) with a Powerflex direct vent. I measured GPM from two 3/4 copper pipes that was used to feed a temp kitchen down the basement and also in the bathroom tub faucet. I did three test bucket fills and the avg has been posted for the hot & cold at each location. No other work was done.

joecaption

More likly there's trash in the shower valve and the anti scald valve inside the control.
Very common to happen after major plumbing work.

wdgates

I'm showing the same % reduction of pressure straight out of the 3/4 pipe as the tub faucet. Should the hot & cold have the same pressure?

ben's plumbing

did the shut off valve to water heater get damaged by shuting off??

joecaption

If it's an old style gate or globe valve and not a ball valve sometimes the shafts inside can wring off inside the valve from being stuck from have not been moved for a ling time.
The handle will still turn but the inside part does not move.
One sign can be the handle turns and turns and never comes up againt a stop.