Shower heads competing for hot water

We have a large shower in the master bath with his and hers shower heads. Because of our schedules, my wife and I find outselves frequently showering together. When I turn on my shower, her shower turns immediately cold (or at least cooler) while mine is getting plenty hot. Anybody know what's going on?

Here are some additional facts that may or may not be a factor:
1. We have a hot water circulation system that uses a pump to circulate water through the pipes, thereby delaying the wait for hot water.
2. The pipe that the my shower head is attached to is higher on the wall than the pipe for my wife's shower head.
3. It doesn't seem to matter who's in the shower first. My wife's shower head is always the one that ends up with colder water but has plenty of hot water if my shower valve is turned off or if I turn my shower head down to cold water.
4. The valve is by PricePfister and is a single handle that rotates 3/4 turn, initially turning on cold water and going entirely hot when fully rotated.
5. The house is less than three years old.
6. All pipes are copper and the water supply is public water (very soft, no water softener needed).
7. And no, contrary to what you smart alecks might suggest, my wife doesn't naturally just turn frigid when she sees me naked!

Thanks for any help you can offer.

It is hard to evaluate this without seeing the pipes inside the wall.

First, we are dealing with a pressure balanced valve; then, with multiple heads there are issues of balancing the flow and pressure.


I think I would start by calling P/P to see if they have any suggestions. If you know who the installing plumber was, you could ask if they used a balancing loop on the heads. Whoa, let me back up. I was assuming here that the 2 heads come out of the wall on separate pipes. Is that true, or are they tee'd off one shower arm? If the latter is the case, I would suggest using identical heads, if they are not already.


Hope I have not confused you too much. Wait a few minutes and some more folks will probably have some suggestions.

Here's more info, Jimbo...

The two heads aren't tee'd off the same pipe coming out of the wall. The are each on a separate pipe and mounted on adjacent walls. And now that you mention it, we recently replaced the head on my shower with one that's different. Although we've had this problem since moving into the house, I think it's probably gotten worse since installing the new, larger head on my shower faucet. Sounds like one way to check out the impact of differing shower heads is to reverse the heads and see what happens. I'll try that tonight.

Thanks for the input!