Hot water problem to tubs

Hot water suddenly went to half flow to tub in master bedroom. Reduced flow to tub for kids also. Third tub, downstairs, is fine, it's rarely used.
Showers, and all other taps are normal flow. Kids bath is tub shower combo. The master bathtub, which is a whirlpool tub, is separate from the shower. This tub also has a shower head, of which the flow is normal.
The problem is the two tubs, hot water side only.
Could something be clogged in both cartridge s?
Incoming water temp, to the house, is 36-40°f.

Wash the clothes washer filling when the sudden drop happened and is it first inline to the other 2 bathrooms?
Sounds stupid I know but in my house when the clothes washer is filling it slows the flow to the 2 shower/tubs I have. It's worse to the master bath because it's farther down the line.

No, it wasn't. The MB is the farthest from the water heater. I tried that tub when nothing else was in use.

Just about all plumbing fixtures have restrictors in them for water conservation. If you got a little some that came into your water system if could possibly have gotten in to a couple of the restrictors.

You may have a clog somewhere. Here's an easy way to backflush and try to clear the pipes.

http://www.plumbing-geek.com/clogged-pipes.html

I put an air gauge on the expansion tank, water came out. I think I know what my first step will be.

Do you have any galvanized water lines anywhere? Even the short stubouts can clog and restrict flow.

No galvanized pipe that I know of.
I bought a new expansion tank, need to put it on.
Would a bad expansion tank cause a problem like this? If so, how? Thier is a tee off the supply line to the water heater, a nipple, then the expansion tank.

Put new expansion tank on. And a new cartridge on hot side of MB tub. No change.
I put a chunk of garden hose on waterheater drain, discharge to floor drain, opened it up. Came out fast at first, then dropped.

You must have some sort of foreign matter that has gotten into your system. Modern valves/cartriges for tubs and showers can get clogged with a very fine particle if it lodges in the wrong place. This is most likely to happen to the valve on the end of the line as well. I have seen this happen many times. It is very difficult to clear the valve/cartridge sometimes, more so than not. You may need the assistance of a reputable plumber...If you don't know one...check with a local professional supply house for a good reference or two....the bets of luck to you...!

Disconnected water heater, both the cold and hot side had junk in them, hot side had more than cold. Kinda surprised I was getting as much flow as I was. With the amount of crap on the hot side.
The check ball that's on the cold side, would it hurt to remove it?

I am not sure of what you are describing as a check ball??? is this a check valve? either way...it wouldn't hurt...how long has it been since you have drained your water heater? Sediment could have built up in there especially if you are on well water which from prior replies, you seem to be. You will need to run a good amount of "clean water" through all of your lines and may need to replace valve bodies and cartridges to rid yourself of this problem. I suggest that you install a large paper cartridge filter in line with the main feed from your well prior to the water heater and cold "T"... I hope things get better soon for you!!!!!

Things got better when I cleaned out the crap built up at the dielectric s.
Thanks for your reply.
That was the first time I've drained the heater. Lived there for 2.5 yrs. House is about 14yrs old, powervent water heater. On city water, surface water. Hardness is usually 60-100mg/l .

Invest in a paper cartridge element filter and install it "whole house"...your problems will never reoccur...expect to change the filter about twice a year...dependent upon sediment...get a clear housing...glad things are better!

Quote:

---

Originally Posted by edw

Invest in a paper cartridge element filter and install it "whole house"...your problems will never reoccur...expect to change the filter about twice a year...dependent upon sediment...get a clear housing...glad things are better!

---

This is key to preventing problems. It's amazing how many times I have seen these filters blacker than black because people forgot or didn't know they had to change them.
Just like furnace/AC unit filters. People never give much mind to changing them. These should be changed every 3-4 months depending on the type/quality of the filter.

Also what kind of junk was you getting out..i have seen the dip tubes in water heaters start to break down and small peices would get caught in the valves and cartridges just a thought also.

Looked like rust. Was building up at the die-electrics. Was worse on the effluent side.
Flow is wonderful now.

Thanks to all for the tips!

My pleasure sir!

Quote:

---

Originally Posted by Skunked again

Looked like rust. Was building up at the die-electrics. Was worse on the effluent side.
Flow is wonderful now.

Thanks to all for the tips!

---

There. Is not an effluent side in potable water pipes