Having a problem with hot and cold water seemingly mixing in my house where some locations can't get cold water and others get a mix of warm/cold from hot settings.
Moved into a new house. Has a brand new water heater and probably not new water circulation system. It appears the water heater (and probably the circulation system?) were re-plumbed for code reasons relocated from the corner of the garage next to the house along that same wall to a more central location along the wall.
Here is what I have observed.
If the water circulation system is off then there is no hot water what so ever in the house.
If the water circulation unit is on then a whole range of bizarre things happen.
The kitchen sink closest to the water heater will have cold water mixed with hot (which equals pretty damn hot) coming from the cold and scolding hot coming from the hot water.
Showers (other side of the house) have alternating warm / cold water. Occasionally they can get fairly hot but only for brief (20-30 seconds) at a time. A luke warm shower (alternating with cold) with the boiler set to maximum is the best possible scenario at the moment with the current configuration.
A deep sink faucet in the garage that is directly tapping the hot/cold lines next to the water heater gets hot and cold water as expected.
Some sinks in the middle of the house get a perfect mix of hot/warm water from the hot and cold from the cold.
External water faucets/hoses on the far side and close side of the house (from the water circulation unit/water heater) pump out water that is very warm or sometimes hot.
What are some of the possible problems it could be?