Hot water pipe disconnected, but when turn on cold water it drains out hot pipe.

So I just installed a K-304-k into a house. The house has been vacant for about 15 months now, so no one has been using the water. I came in and replaced the valve, and closed up the wall. I installed all the fixtures, and sure enough, no hot water. It comes out in a slow trickle. Here are...

When I run the hot tap, the water runs hot then cold, hot then cold. The boiler ignites when the tap is turned on but then goes off and on, off and on while the tap is running. I have a ravenheat LS80(T) combi boiler

Hello. Cold water pressure relief valve start to drip water through the drain pipe. I replaced it with a new one but it is also dripping water. I have reduced water pressure in the house to the minimum by turning main water supply valve but it still leaking. Thanks for your help.

I recently purchased a rental house. I replaced the hot water heater and shut off valves. With the shutt-off in and out of the tack are closed, I still get cold water from the hot side of all faucets in the house. When valves are open, and temp. Set at very hot, I get semi-hot water.