We've recently renovated a 2nd floor bathroom in a rowhouse we just bought -- all new plumbing going up from the basement. We installed Grohe Atrio shower fixtures with a port diverter at the shower control. With the tub spout turned on, after a few seconds water begins to come from the shower head. When the diverter is engaged, the shower works fine.

I saw some answers to this same problem on this site where the response was that water pressure may be too high. However, our plumber is blaming the problem on pressure being too low, saying that the diverter doesn't "catch" or something. Unfortunately the wall is tiled and finished. I would say that, while not a problem elsewhere, it sure doesn't seem like we have a ton of extra water pressure. Also, we have a 40 gallon water heater and basically everybody has said that we should have a 50 gallon for our house. Unfortunately I don't know what the water pressure coming in from the street is. What are our options? Thanks in advance.

To find out the pressure you need a water pressure test gauge see the image below, the water pressure should be 40-60 psi, high water presuure or a faulty diverter could cause the problem you have, check the water pressure first and let us know, Thanks.

John

For the plumber to make this claim he must have measured your water pressure, what did he say it was? About 40-45 psi would be just great

Ok, I'll do that. I'm pretty sure that he has not measured the water pressure, and that he's just saying that it seems very low overall. This gauge, can it be installed anywhere or is there a specific valve that it needs to be attached to? Thanks.

You need to attach the water pressure gauge to the outside faucet where you use the garden hose, Thanks.

John

I live in a Brooklyn rowhouse, so unfortunately there's nowhere to attach the pressure gauge anywhere close to where the water comes from the street. The only hose bib I have outside is in the backyard, well behind various branches of the pipes. That said, the gauge there measures 60psi on the nose, so it would appear that low pressure is not the problem.

Also in the basement I have hose bibs for drains for the hot and cold pipes running up to the bathroom in question. Should/can I measure the pressure there by attaching the pressure gauge and opening the valve?

We installed Grohe Atrio shower fixtures with a port diverter at the shower control. The diverter's built into the valve. Correct?

the gauge there measures 60psi on the nose You have 60 PSI and the plumber blamed "low pressure"?
HOGWASH! He's blowing smoke up your skirt. He hasn't a clue!
Your condition is caused by one of several things.
1) Excessive pressure, If you have a PRV (pressure reducing valve) scale the pressure back to 45 PSI **OR**
2) Too short as shower raiser from the valve, What's the measure from the center oif the valve to the shower arm coming out of the wall?
I should have added;
3) Trash in the built in diverter
Let me know, Tom

Thanks for answering. I was pretty sure it was BS as it was leaving his mouth. That said, the water pressure at the faucet doesn't FEEL especially gushing, so it seems unlikely that it's high pressure.

Yes, the diverter is built-in to the valve. This is the unit:
http://common2.csnimages.com/lf/1/hash/967/916323/1/Atrio+Pressure+Balance+Diverter+Valve+Trim+with+Le ver+Handle.jpg

The contractor thinks its either a defective valve or that there's dirt/grime in the diverter. Luckily he's committed to fixing it.

Thanks for the update and I am with the contractor a defective valve or dirt will cause this problem, if that wouldn't fix the problem, Next thing short shower raiser from the valve to the shower arm ear elbow will give you the same problem as Tom says, but I am sure the contrator will resolve your issue, Good luck.

John

Ah yes, forgot to mention that I am at work now and so will measure the height of the raiser when I get home this evening. Thanks for all your help everybody!

after a few seconds water begins to come from the shower headYes, it could be trash in the diverter causing it not to close The fact that it takes a few seconds to get op the shower raiser tells me it's a slow leak through thr diverter. But that's just a guess. Let us know the outcome. Good luck, Tom

For what it's worth, height from center of valve control to center of shower arm is 43 1/2".

Thanks for the update, so the shower raiser shortage is out of question 43 1/2" is on the high side, for more information regarding the critical dimensions open the link below, Thanks.

John

http://www.moen.com/shared/pdf/l82691sp.pdf

Thanks, I had a feeling we were all right on the shower height, both my wife & I are pretty tall.

Just thought I would update this topic/question with the result. Plumber came and opened up the shower fixture, and opened the diverter cartridge, and it was indeed faulty (a hole in the gasket or something; I wasn't here when he did it.) Anyway, Grohe is sending a replacement gratis even though they suspect it was damaged in installation.