Why do I get cold water only when I flush the toilet, until it cycles completely?

Hi Camaro:

With the information you provided at another post I think you should see if the shutoff going into the water heater is in the fully opened position?

Another thing to check is the MAIN WATER SHUTOFF... could be that the plumber had to shut this to install the water heater. Check the main shutoff and the water heater shutoff to see if fully opened.

Let us know what you find...

Mark

Thanks already checked... Another discovery is that if the hot water is alreaday running, flushing toilet does not effect the water pressure, only trying to turn HW on after toilet is already flushed results in no flow of water at all..

If a plumber installed this then call him back and see what he thinks about this...

Most likely one of the shutoffs that he touched has malfunctioned and won't reopen as needed. Sometimes with older valves... especially GATE VALVES... they'll close fine, but can malfunction and only open a little or, in some case, not at all... ;)

Are you on a well or city water... let me know?

Also, if you do have an old-fashioned gate valve shutoff you should know that it can take up to 20-25 turns to open the valve completely.

Let me know what you know...

Mark

City water

Only guessing, but I'm betting on a faulty shutoff as mentioned. Above. Call the plumber back and have him look at things...

Good luck!