natural gas requirements

I have all gas appliances in my residence including a gas fireplace. I want to add a generac 17kw natural gas generator and a 400,000 btu natural gas pool heater. I got an estimate from two local plumbers to install the gas lines. One plumber quoted $600.00 to connect both generator and pool pump to the existing meter while the second plumber says that he would need to convert the meter to high pressure, and add three new regulators otherwise nothing is going to work properly and may result in damage to the generator motor by making it run lean if anything such as the residential water heater, stove etc. is used in conjunction with the generator or if the pool heater is in use when the generator runs its weekily test. The second plumber wants to charge $3500.00. which one is doing it correctly?

The second plumber is correct. The gas meter and lines must be able to provide adequate gas so that all appliances can be run simultaneously. I doubt very much if the local jurisdiction would allow the first application and was probably going to be installed without the proper permits.

To make a comment without fully evalauting what is presently there and then commenting on it would not be fair to you or either plumber. Consider calling in a 3rd and 4th if the estimates are free and see what they say. If all else fails call the gas company and get their input. Maybe they can be of assistance. Or the local build code department.

Sorry wish I could be more help, but without knowing the EXACT situation, I prefer not to comment and would tell you to seek other professionals in your area for further guideance.

The first thing to do is to make sure that contractor bidding on the job is a properly licensed HVAC contractor. (I would not hire a plumber.) 2nd, note that some or all of the supply piping may have to be enlarged based on where the 400K heater is being added (at the end of the longest branch or on a branch close to the meter). Have each contractor show you that they’ve done the proper calculations using TABLE G2413.4(1) through TABLE G2413.4(8). (That’s if the IRC is the appropriate code there.) The IRC code below states one method of calculating the pipe size (you have to use the tables).

G2413.4.1 (402.4.1) Longest length method. The pipe
size of each section of gas piping shall be determined using
the longest length of piping from the point of delivery to the
most remote outlet and the load of the section.

It’s impossible for us to know about the regulators or meter without more info on your pressure and the demands of each appliance in the system.

Finally, you may want to get a 3rd estimate to see which one of the two is way out in left field. Personally, I would want to understand exactly why they are doing what they say and upon what the decision is based (make them show you the math).