HELP! Hot and Cold Water Surges in Shower ?

Help! - My tenant is calling me with a real stickler of a plumbing problem and need help diagnosing and fixing / solving this one.
DAY1-I get a call that the Hot/Cold water surges in the 2nd floor bathroom (duplex/upper flat) shower. The Tenant downstairs is out of state so that person can't be flushing the toliet or anything like that (rules out the downstairs plumbing activity).
I inspect the case: I go to the shower in question, turn on the water to a steady warm condition, and then go to the bathroom sink and turn on the cold, feel the bath water (remains the same). I go to the kitchen and turn on the cold (bath remains the same), turn on the hot, (bath water remains the same)???
I go to the basement to check things out with the water heater. The water heater is leaking bad from the bottom and is SHOT. I replace the water heater with a brand new 50gal/water heater.
3-4weeks pass, I think - replacing the broke water heater must of fixed that problem.
Well I get a call from the 2nd Floor Tenant again today - " The water is surging hot/cold (I don't get the exact behavior but get the gist of the problem) still inside the shower" I believe the hot water gets too hot and burns the showeree or it gets too cold one or the other.
I lived in that apartment for 9mon to 1 year and never experienced this "surging shower water problem." Can't be the person down stairs either.
I need some help diagnosing and fixing this thing for good. Any advice and insights much appreciated.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Sounds like a pressure balance promblem what brand of taps is it and I can probaly to check. Is the pressure surging or is the temp changing snipped-for-privacy@hotmail.com wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jim,
Hey thanks for the information!
I did do some follow up. I called the Tenant and he states:
"The water coming through the tub facet seems to be fine and runs a normal warm temperature. It's only when you turn on the the shower, like every time first thing in the morning, the water temperature fluxuates, where you need to adjust the H/C controls or stand out of the way of the hot water. It's weird." Also, he goes on to say that the water temp doesn't change as much in the shower during "the afternoon timeframe" when taking a shower. He goes on to say this is very reproducable problem especially in the mornings.
Side note: To turn on the shower there is a center knob inbetween the H/C knobs. Could this on/off shower tap or the (or a minerlized) shower head be causing this?
Any other questions I need to ask or any additional thoughts on this one?
Thanks again,
jim wrote:

.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Iam not sure why the time of day would make a difference but I would start at checking the shower diverter the handle in the middle. Take it out and check the washer on it or replace the diverter if you can usually thread out and thread back in new one make sure to turn off supply. also take the head and soak it in Lime Away if you are in hard water if these taps are 15 yrs or older you might want to look at replacing them let me know how you make out. Really sounds like the diverter is the promblem snipped-for-privacy@hotmail.com wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Just reread your first letter and thought of something you might have some losse solder from the tank install that has come up the pipe and jammed in the diverter . When you have it out run the water out of it into a pail and see if you get any solder. also take out the valves and stick fine wire through the valve body to knock it out. remove all valves for this and replace then try. jim wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.