Generac 22kw- Nat. Gas Regulator Size?

10,790 Views | 17 Replies | Last: 4 yr ago by jt2hunt
RulesForTheeNotForMe
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In the final stages of getting this hooked up at our house. Anyone know what size Nat Gas regulator this thing needs coming off the supply line from the utility meter before it's hooked up into the Generator itself?

Plumber I hired for the city permit inspection doesn't have a clue & can't get Centerpoint out to upgrade the main meter until this permit clears.

TIA
Dr. Venkman
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Wouldn't you just add up all the gas appliances in your house? The Generac should have its needs on the spec sheet.

https://www.generac.com/generaccorporate/media/library/content/all-products/generators/home-generators/guardian-series/generac-20-24kw-spec-sheet-without-pwrview-a0000937814_2.pdf

327 cubic feet/hr = 327k btu

plus whatever other gas appliances are in your house.
RulesForTheeNotForMe
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I've done that part and Centerpoint knows what they need to bring out. I'm having trouble determining what regulator needs to be installed from the post CenterPoint meter to the generator itself.

We have run the designated gas line from the meter point to the generator itself, but now need to right size gas supply into the generator itself.
Dr. Venkman
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The spec sheet above says:
Required fuel pressure to generator fuel inlet at all load ranges - 3.5 - 7 in water column (0.87 - 1.74 kPa) for NG.

I'm pretty sure 99% of residential pressure regulators at the meter are 7 in water column. So you'll just run the pipe from the meter directly into the generator. (with a valve and drip leg) No post meter regulator is needed.
akaggie05
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Dr. Venkman said:

The spec sheet above says:
Required fuel pressure to generator fuel inlet at all load ranges - 3.5 - 7 in water column (0.87 - 1.74 kPa) for NG.

I'm pretty sure 99% of residential pressure regulators at the meter are 7 in water column. So you'll just run the pipe from the meter directly into the generator. (with a valve and drip leg) No post meter regulator is needed.


This. Unless you have a 2 lb system (not likely), just hook it up and let er rip.
akaggie05
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Nm
RulesForTheeNotForMe
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Y'all are awesome. One more clarification.......

Just got this back from Centerpoint. So with that info, now what?

We have received your request to upgrade your meter at XXXXXX XXXXXXXXXXXX due to a generator installation. With an upgrade, you will go from 4oz. regulator to a 2 lb. regulator.

So do I need to regulate that back down now?
P.H. Dexippus
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Whether you need the meter upgrade depends on a number of factors, including overall demand, distance from the meter to the generator, and pipe size. I would think your plumber should be able to calculate it for you. If you do upgrade to 2lbs, you will need a regulator at the generator (and at least as the supply enters your home, if not the fixtures themselves) to drop the pressure.
RulesForTheeNotForMe
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Currently have a 250k btu meter supporting 210k btu in total appliance hook ups.

Generator kicks the total hook up btu to 540k btu which is what triggers the meter upgrade.

I assume I can just have two different regulators installed off the main supply coming off the main meter? 1 near the generator and 1 near the house supply inlet rather than having to add regulators everywhere.

Plumbers have been pretty worthless thus far tbh.
IronMan92
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When I had my meter upgraded for my pool heater install, the main regulator and gas meter were upgraded on the main line. The small regulator for the house appliances was left alone off one of the branch lines and I have another small regulator (on the other branch line) before it goes to the pool heater. Hope this helps.
RulesForTheeNotForMe
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Perfect, thanks everyone.
Dr. Venkman
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RulesForTheeNotForMe said:

Currently have a 250k btu meter supporting 210k btu in total appliance hook ups.

Generator kicks the total hook up btu to 540k btu which is what triggers the meter upgrade.

I assume I can just have two different regulators installed off the main supply coming off the main meter? 1 near the generator and 1 near the house supply inlet rather than having to add regulators everywhere.

Plumbers have been pretty worthless thus far tbh.
Correct. I would get two of these:
https://www.supplyhouse.com/Maxitrol-325-5BL-3-4-3-4-Line-Regulator-600000-BTU

Inlet pressure is 2 psi and outlet is 7" w.c. 600k btu which is technically overkill for what you need at your house, but gives you the freedom to add a gas tankless water heater in the future.

Also need two vent protectors:
https://www.supplyhouse.com/Maxitrol-13A15-5-3-8-NPT-Connection-Vent-Protector-for-325-5-and-325-5L
akaggie05
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Quote:

Plumbers have been pretty worthless thus far tbh.

That's unfortunate and I'm not surprised. Just went through a pool build and all the accompanying electrical and gas line installs last year. I honestly wonder how crappy the whole setup would have been if I didn't halfway know what I was talking about and wasn't out there every day double checking their work. Had to argue with the electrical subcontractor about installing a second 20A 240V circuit to the equipment pad (added up the running amps from the nameplates of all the pumps and other equipment and was well above 20). Then had to argue with plumbing sub doing the gas line to the heater (400K BTU/hr heater and they wanted to run 1 1/4" line... busted out the tables and showed them that the length of the run called for a 1 1/2" line). Sounds like you're being proactive and on the right path here... good luck with the rest of the install.
Jack Pearson
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I am building house and putting in a 24kw generac along with a pool heater etc. I want to get the 2lb meter installed from the getgo, it was my understanding this was a no charge deal if you requested it up front?
akaggie05
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Depends on where you live. For me (Dallas, with Atmos as gas company) they would do whatever I want (larger meter, upgrade to 2 PSI, etc.) for free. Have heard it can be different in other places.
Edit: to be clear, this was having them come out to mod existing service.
jt2hunt
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We have installed over 300 in Austin and DFW this past year. The generator has an internal regulator. You only need to install a regulator if you are upgrading your meter to a 2 lb meter.

jt2hunt
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Yes, you will need to install a whole house regulator and one for the generator. OR You can install regulators at each gas appliance.
jt2hunt
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The utility providers do not charge to upgrade the meter.
The generators increase your BTU load by about 300,000.
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