Funny sounds and pressure drop at shower issue

Hi ... I rent a home that was gut renovated four years ago, so everything is new (including plumbing). My master shower is at the back of the house, as far from the street mainline and the hw heater as possible. When we moved in, we noticed the pressure all over the house was poor. Called the city, they tested, agreed it was below spec, and ripped up the street to connect us to a different main. Slight improvement.

My local sprinkler guy adjusted a water pressure control valve someone had installed long before the renovations, and voila! Huge improvement in water pressure. We're liking this now!

BUT ... we have an issue with the master shower only. It's a Pegasus single level control, so full hot equals full pressure. I like full hot. When I crank it wide open, there is a chugging sound, followed by a precipitous drop in pressure, down to a dribble.

I've cleaned out the filter screen in the shower head, no improvement.

Could there be some kind of pressure control in the Pegasus fixture? Or a temperature control mechanism that could cause this?

Thanks in advance for any/all suggestions.

Dennis In Austin

It will have a balancing spool in the valve.

If the pressure is uneven, either the hot or cold inlet is partially blocked, it will reduce the pressure

pegasus

It will probably have a balancing spool on the lower right side after you remove the large trim plate. You will probably NOT be able to find a replacement at most big box stores, but since it is made by a slightly common manufacturer, a well stocked plumbing supply store might have one. But you will have to take the old one with you to match it. I would have to look in my junk pile to see whose it is.