I have a 3/4" black pipe coming in from the outside meter. It goes to the utility room and feeds the furnace (reduced to 1/2") and the water heater (also reduced from 3/4" to 1/2"), The 3/4" also goes to the far end of the house to feed the stove and the gas dryer. I want to install a second 50 gallon water heater in parallel with the present water heater. If I use a 1/2" tee for the gas line that presently feeds the current water heater, will it also be enough gas supply to feed a second matching water heater? Keep in mind that worst case scenario is that the furnace is drawing gas, both water heaters are drawing gas and the clothes dryer at the far end of the house might be drawing gas. Everything works perfectly right now. Please don't suggest a tankless. I have considered one and it is way too expensive for the payback time involved and the venting nightmare.

Hi Jeff

I would need to know the distance from your gas meter to the farthest gas appliance in the home.

I also need to know the BTU input and output of your furnace... I can assume the other BTU requirements for each gas appliance mentioned... ;)

As depressing as it sounds, it doesn't look good for adding anything easily!

Get me the numbers...

Mark

Oh boy... Here goes! From the meter to the farthest appliances (stove and dryer) it is about 66'. It is about 30' from the meter to the Furnace and water heater. The 3/4" pipe is reduced to 1/2" and runs 24' in 1/2 inch to the dryer/stove. As for the furnace, it is 110,000 BTU input and 89,000 BTU output. I just remembered that where the 3/4" feed reduces to 1/2" to feed the stove/dryer, it also branches off to feed my gas fireplace type heater on my sun porch. If you need any more information I will get it for you, and BTW... I appreciate your time.. Jeff

Hi Jeff

Unfortunately, as calculated by my code book, the existing piping system you have right now is undersized. Adding an additional 50 gallon gas-fired water heater will definitely compromise the VOLUME of gas delivered to the appliances in the home and will be a problem, especially at times of peak demand.

By my calculations your gas main need to come into the home as a 1" pipe (can accommodate up to 240,000 BTU/HR). This 1" gas main would need to stay 1" past the furnace and up to and including the two water heaters (branches to each appliance reduce appropriately)...it could then reduce to 3/4" to feed the other appliances.

Specifics beyond that would require a lot more information and will not really be helpful to you at this time anyway.

If you still want to add the additional water heater consult with your local gas company and a licensed gas fitter or plumber, OK?

Back to you...

Oh well... I guess I can continue taking lukewarm showers.. Thanks for working with me, I really appreciate it.

If Gas is a problem, you could use an electric heater if you have capacity in your box. I started to do piping calcs but glad Mark got there first.

I know... bummer! However, as Ma0641 pointed out, an electric water heater could work here.

Otherwise, getting the gas main repiped really shouldn't be too big a deal if it is important enough to you... ;)

Thanks!