To where are you targeting the delivery of it? If to a dishwasher or washing machine, a simple method is to run a faucet near the machine until the flow is hot ... such as at the kitchen sink. Otherwise, pretty much the only way is via a recirculation pump on a flow loop from the water heater across all the taps. Some plumbing systems are constructed with a dedicated recirculation loop. There are retrofit pumps that are installed at the furthest usage point from the heater, feeding water from the hot line into the cold to create a flow loop ... usually operated on a timer or on-demand a few mins before hot water is needed. One such product is the Metlund D'MAND System. There are others.

hi rachel/baymee. thanks for the response. this water feeds into furnace that provides central heating. i am just concerened that the existing one doesn't have enough BTU. one plumber recommends replacing the existing 40gallan tank with 50,000 BTU/50 gallon, based on what the neighbor has. another one just said the existing one is good enough.. will there be issue with capacity and BTU with the curent tank? thank you.

I think it is just coincidence that the t and p valve is dripping after the furnace was installed, unless of course they bumped open the lever or manually opened the t and p valve and it wouldn't reseat itself properly. A t and P valve will only open for 3 reasons 1) excessive temperature 2) excessive pressure 3) a bad valve Ask the company that installed the furnace if they possibly opened the valve or perhaps bumped it, failing that I would probably try changing the valve or getting a water pressure test meter and see what the actual pressure of the water in your home is If it is high80 or abobe then you may have to add an expansion tank to the water heater

You should check either with your local gas company or with your Town to find out about building codes, and to make sure you are not in violation. You probably need a new water heater. The useful life of these things is 20 years the most. They usually quit very suddenly and leave a big flood. You should consider yourself lucky that yours is "warning" you that it's time to replace it. The new gas heaters and water heaters are much more efficient than the old ones. Your gas bills will be lower. And, because of their higher efficiency, they emit less smoke. Therefore, even if your chimney is too small for your currect system, it may be fine for a new one. But you do need to get impartial assessment from either the gas company and/or your local municipality. Your system may have been approved according to codes that were used when the chimney was build years ago. But it may now be a violation because codes may have been updated. In that case, your system may be okay if there is a "grandfather" provision that avoids forcing all homeowners to update their systems.