I live in a condo where there are 6 units to a building. I recently had to shut off the water supply to the entire building to replace a hot water tap in the kitchen dishwasher as part of a remodeling project (lots of banging, tearing). Now my neighbors downstairs are saying that they don't get any hot water in their kitchen (it's directly below my kitchen)--only cold water is available from the hot water tap. Every other room in their units (bathrooms, washer) have hot water.

There are 3 units on the bottom floor, 3 units on the upper floor. The units on the upper floor are working fine--hot water available on all rooms. But even though we don't have any faucets hooked up to our kitchen taps, we ran a hose to the outlet and felt that the pipe is hot--we're getting hot water.

What could be the cause of this? It is just strange. The faucets on the lower units should be Price Pfister, single handle units. I went into a unit below and turned off the cold water tap and turned on the faucet but the water is still cold. I turned off both cold and hot water taps and no water came out, as expected. There is only one water heater to the entire building. I can understand crud from calcium buildup (we have hard water) preventing the flow of hot water but why would the top units get hot water and water pressure from the hot tap unchanged?

Thanks for any advice the experts can provide.