When hot water is flowing, the cold water isn't!

[sxiang]

below is the problem.
i turn on the hot water a little, nothing.
i turn a bit more, a little water comes, but with a pumping sound
i turn a bit more, more hot water,
i turn the cold water, still burning hot
i turn the cold water more, still burning hot
giving up, i turn the hot water off.
i keep the cold water turned on, nothing
i turn the cold water more, it comes after 10 sec delay.

the only way to have a shower is
turn hot on, turn hot off, turn cold on, turn cold off, repeat repeat repeat, until no more pumping sound, no more bubling sound, and eventually, cold and hot water come.

i hate this.

 

[phishfood]

Does your system have a tempering valve on it? This would be installed by the water heater, and have a pipe from the hot side and another from the cold water leading into it, then one more line coming off of it feeding the hot to the rest of the house.

This is all that comes to mind, but if you can give a little more detail of your situation, perhaps we can be of more help.

 

[IFIXH20]

Post a photo of the shower valve .

 

[AQualityPlumber]

A possibility is if you have galvanized piping in your home or even just your main line is old, corrosion can build up and plug the cartridges and ports in your valve. This could possibly explain why you get irregularities on both sides of the valves. Pressure balance valves will also be effected on both sides even if just one side is plugged.
This typically becomes an issue after shutting your water off for service.

 

[johnjh2o]

It sounds like like you have a balance pressure shower valve and the balancing spool is sticking. If it's a Moen or Delta faucet call there customer service and they will send you a new cartridge free of charge.

John

 

[Beni]

If you have a two handle shower my next question is if pressure is fine at other faucets. If the pressure is low everywhere you might have a pressure reducing valve on the water main that's gone bad. If its only at the shower, remove the shower head and check the flow. If its low the flow restrictor in the shower head may be the issue. Drilling it out might help.

If it low everywhere then its a PRV or water meter issue. Or a bad / closed gate valve upstream.

Also possible that there is a screwdriver stop on the cold side that is closed or clogged. or a clog in the cold water pipe at the valve.