[fdee]

If I have 1 inch pipe originating from the meter, can I install 1 1/4 inch pipe branch after that for my tankless water heater?

[massplumber2008]

You are probably better off using a brass 1.25" to 1" reducing bushing at the ports of the water heater....nothing gained by increasing the pipe size, so why pay for the more expensive materials?

Mark

[fdee]

You are probably better off using a brass 1.25" to 1" reducing bushing at the ports of the water heater....nothing gained by increasing the pipe size, so why pay for the more expensive materials?

Mark

Hi Mark;

The water heater requires 180,000 BTU, so to my understanding, 1 1/4 inch pipe is required to supply the correct capacity. The current heater of course has 3/4 inch pipe. From the meter, the first 30 feet of pipe is 1 inch. So, my question was, could 1 1/4 inch pipe be coupled after that and still provide the correct capacity to the water heater. From further research, it seems that configuration would not provide enough capacity because of the first 30 feet being 1 inch.

So, there is a 20 inch long 1 inch pipe coming through the wall from the meter to the first 90 degree coupling. Can I start the 1 and 1/4 inch pipe at that point and still have sufficient capacity for the Tankless 80 feet away?

Best Regards! :)

[speedball1]

Your feet that 1 14" pipe with a 1 inch source. Your volume is determined by the size of the source. As Mark suggested bush the heater down. Good luck, Tom

[massplumber2008]

Is this a commercial water heater? If it is then I need to ask you if you are asking about pipe size in terms of GAS or WATER.

If you are talking water, then you bush down to 1" as I originally stated as there is nothing to be gained by increasing the pipe size as 1" coming into the home/meter is the determining factor.

If you are talking about gas supply, then you call your gas company and have them increase the pipe size (and may also be a meter replacement here) to 1.25" or even 1.5" as that is the only way you can achieve the required BTU and still be able to run all the other gas appliances during peak water heating.

Mark

[fdee]

Is this a commercial water heater? If it is then I need to ask you if you are asking about pipe size in terms of GAS or WATER.

If you are talking water, then you bush down to 1" as I originally stated as there is nothing to be gained by increasing the pipe size as 1" coming into the home/meter is the determining factor.

If you are talking about gas supply, then you call your gas company and have them increase the pipe size (and may also be a meter replacement here) to 1.25" or even 1.5" as that is the only way you can achieve the required BTU and still be able to run all the other gas appliances during peak water heating.

Mark

Mark,

Yes, this is a residential water heater replacement and I'm inquiring about the proper size pipe for supplying the gas so that the unit operates properly. The current total BTU is 230, installing the new unit would take it up to 372, a difference of about 142btu's. So, in this case, you think the house would need to have a larger meter installed?

Also, there is a 1 inch pipe coming through the wall from the gas meter that's about 20 inches long. Can 1 1/4 inch be connected at the joint to begin the run of new pipe. Would the 1 inch pipe from the meter to that point have a big effect on the supply of gas downstream??

Thanks!

Fletch

[ballengerb1]

If your water heater is requiring 180,000 BTU it's likely a tankless on-demand heater and increasing the size of the pipe after the meter will still choke the volume of gas per hour needed. Talk to your gas supplier about what it will take to provide you with the right sized pipe

[massplumber2008]

Hi Fletch

Yup, you need to talk to your gas supplier. Here, you may not necessarily need to upgrade the meter size, but you won't know until you talk to the gas company. If a meter upgrade is needed the gas company usually pays for the meter upgrade and then you pay from the meter forward for a plumber or gas fitter (or you?) to pipe the main to proper size up to the water heater. If you plan on doing this work/upgrade yourself you should know that gas piping, flue work, safety switches (such as spill switches), chimney draft/approval, and CO detectors amongst a bunch of other things on a job like this require a GAS and a PLUMBING PERMIT and very specific tests to confirm all is safe.

Let us know what you think...

Mark

[fdee]

Hi Fletch

Yup, you need to talk to your gas supplier. Here, you may not necessarily need to upgrade the meter size, but you won't know until you talk to the gas company. If a meter upgrade is needed the gas company usually pays for the meter upgrade and then you pay from the meter forward for a plumber or gas fitter (or you?) to pipe the main to proper size up to the water heater. If you plan on doing this work/upgrade yourself you should know that gas piping, flue work, safety switches (such as spill switches), chimney draft/approval, and CO detectors amongst a bunch of other things on a job like this require a GAS and a PLUMBING PERMIT and very specific tests to confirm all is safe.

Let us know what you think...

Mark

Got cha! At this point, I'm actually thinking more about returning the Tankless Rinnai unit and just having a regular storage tank heater installed... Just appears to be too much of a hassle to retro-fit an old house with one of these units as a main heater.. Thanks for all of your responses!

Fletch

[ballengerb1]

Tankless are really great for some homes, your useage and style make the difference. Ckeck with Rinni and other suppliers to see if any of their other units only require a 1" gas line. Since installing mine a few years ago they have made many improvements, some even vent via a PVC pipe rather than a stainless chimney.