Gas Meter for 400,000 BTUH meter

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R

rhawke

Bronze Supporter
Nov 27, 2017
261
Houston, TX
Hi,

I'm getting conflicting info in the required gas meter needed for my home.

We have
40,000 furnace
200,000 on demand hot water heater
60,000 outdoor bbq
400,000 pool heater
Total: 700,000 but we probably won't run everything at once.

The pool builder initially told me that the current AC 250 gas meter should be good enough even though the gas company will try to get us to upgrade. From what I understood the AC 250 meter is for 250,000 btuh which would not even be enough for the heater alone? I called the gas company (CenterPoint) and customer reps appear clueless. They said the pool builder typically determines if a meter upgrade is necessary.

So do I trust the pool builder on this?

If you are in the CenterPoint Houston area and you have a 400,000 gas heater, would you mind posting a picture or model number of your gas meter?

Thanks,

Robert
 
That's funny I have the same exact question, but only have a stove and gas fireplace.

Jandy rep was out and said I needed an upgraded meter to 400KBTUs for my 400KBTU heater.

I called gas company and got same clueless answer.
 
I JUST went through this in PA with our power company, PECO. We currently have:

100K gas furnace
50K gas range/oven
50K hot water heater

We are putting in our NG pool heater and decided to downsize the heater from 400K to 333K. We needed a meter upgrade to get to 425K service (which we did) - I was originally told by PECO (gas co) that we wouldn't be able to run the pool heater and our furnace at the same time even with the meter upgrade. We were originally planning to upgrade our main line (big $$ for us) but after talking to 2 plumbers and other PECO techs they said we'd be more than fine with the downsized heater and everything else. They told me that the meter rating is a even a bit underrated/conservative (20-25% or so) as well. All of my neighbors (13 or so have pools w/ NG heaters) have the same setup with 0 issues.

I would think you for sure would want to do the meter upgrade - not sure about your area but they didn't even charge us.
 
I live in Houston area and upgraded my meter with Center Point because of my PB recommenadations. I have gas water heater for house, gas furnace, gas dryer, gas cook top stove, 2 gas fire places, gas grill, 2 fire bowls around pool, 400btu gas heater for spa. Yes there is a good chance my spa heater, house heater, fire bowls, fire place , and grill might be on at same time. PB said it would affect the spa heaters efficiency if all were running.
 
the pool builder just called me because i was very unhappy with the situation and said he would hook up the heater today and that it would be absolutely ok to use as long as we don't use other gas appliances in the house. he said even though the meter says class 250 and the heater is 400,000 it is no problem to operate that heater on the 250 meter for a temporary period until the gas company comes out and installs the meter.

any objections?
 

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Not only is the meter substantially undersized for the heater, it's undersized for everything in total. If there is anything else operating at the same time as the heater, the gas pressure will be that much lower. Insufficient gas supply will void the warranty. The first thing a service person would check on a repair or warranty call would be if everything was installed to code.

Even if the issue was not related to gas supply, they might still deny a warranty claim based on improper installation.

Also, everything else on the same meter would be getting insufficient gas supply. You could potentially damage every other gas appliance that tried to operate at the same time.

It's pretty simple, the gas meter is rated at what it's rated and that's what it can reliably do.

If you choose to overload it, it's at your own risk.

It's analogous to putting 40 amps on a 25 amp circuit or 4,000 lbs in an elevator rated to carry 2,500 lbs.

Will the wires burn down the house?

Will the elevator cable snap and send the elevator plummeting toward the ground?

Maybe, maybe not, but is it a smart thing to do? No, it's not.

Gas and electricity are two things that you should always be extra careful about following code. Do it right.
 
JamesW said:
Not only is the meter substantially undersized for the heater, it's undersized for everything in total. If there is anything else operating at the same time as the heater, the gas pressure will be that much lower. Insufficient gas supply will void the warranty. The first thing a service person would check on a repair or warranty call would be if everything was installed to code.

Even if the issue was not related to gas supply, they might still deny a warranty claim based on improper installation.

Also, everything else on the same meter would be getting insufficient gas supply. You could potentially damage every other gas appliance that tried to operate at the same time.

It's pretty simple, the gas meter is rated at what it's rated and that's what it can reliably do.

If you choose to overload it, it's at your own risk.

It's analogous to putting 40 amps on a 25 amp circuit or 4,000 lbs in an elevator rated to carry 2,500 lbs.

Will the wires burn down the house?

Will the elevator cable snap and send the elevator plummeting toward the ground?

Maybe, maybe not, but is it a smart thing to do? No, it's not.

Gas and electricity are two things that you should always be extra careful about following code. Do it right.
Click to expand...

Thanks for the explanation. I'm really surprised they put in the 250 gas meter. Because this is a brand new house, the new meter is only a couple of months old. If I were to run the hot water heater and at the same time my outdoor BBQ I would already exceed the 250,000 btu. So the gas company installed an undersized meter even for the house load?

I'm also surprised the plumbers are willing to hook up the heater if it is against code. They are licensed and are getting inspected by the city. Well, I'll let them do what they do today and then wait until I finally get the call from the gas company about the meter upgrade.
 
As James states, go w the upgrade. Provide all the BTU's to the centerpoint rep and they will install the correct size regulator, which is going to be a $300-$400 one-time upgrade and install cost. After that, there's no more of a cost than the smaller regulator. It's all variable from that point forward.

The meter should be sized as if you were running all gas appliances at one time and the regulator can meet all of those needs. It's a spec and safety regulation...an undersized gas flow can create all types of nightmares for your gas equipment. good luck.
 
I just added a 260btu raypak end of summer and Im in NJ with NJnatgas. I had a 250btu meter and I had 260btu max load if everythings on at once. never had an issue and I called as a customer/contractor and requested the upgrade. sent a guy out free to evaluate and he stated meters are undersize and can do 50% more than rating but I was cutting it close. I said upgrade meter please and he said no prob. few days later 2 guys came out and I had done my piping in meantime and left it easy for them. mine was rusty and crappy and they brought a 500k btu w them and after looking they had a 700k btu in truck and threw that in instead, was easier to pipe for them in the end. I ran the heater before the 250kbtu was taken out and tested the manifold pressures w my manometer and it was actually fine needed a slight adjustment. Only water heater,stove and dryer would run in summer and they are 150k btu together max so 400ish would have been fine but the design is for total equipment max input and as stated low input pressure will give you a poor flame and soot up the unit. whoever does the install for the builder ask him to set the pressure w a manometer you will get best performance. nat gas is very forgiving most just install and walk away and it works fine regardless of pressure, but it can be set better
 
Thanks for all the comments. Well the plumber came yesterday, hooked up the heater and said it's simple: the pentair mastertemp heater has a built in shut off valve when the pressure is too low. So that's why they always just hook it up and see if it works first.

Before I let him turn it own I called Pentair and asked them if that is correct and the service rep confirmed it. He said the heater won't be damaged because if the pressure is out of specs the heater will turn off anyway.


So I let the plumber turn it on and it worked fine. For now I will turn off the tankless water heater while heating the spa to avoid any risk for the equipment inside the house and I hope that Centerpoint will come out soon. I will let them take a look at it and do whatever they recommend. (I assume they will want to upgrade and charge the 350 since they already came to take a look :)

I checked how much gas was being consumed with the heater running and I counted approx 6 cf per minute = 360,000btuh per hour.
 
The heater doesn't have any way to sense the gas pressure and automatically shut off if the gas pressure is too low or too high.

If it did, there would be an error code or light for gas pressure out of range, but there's no such thing.

It does have a sensor that detects the flame. If the flame is significantly degraded, it might shut off the heater, but it's not a good idea to run like that.

There is a water pressure switch that detects water pressure, which is a proxy for a flow switch, but it has nothing to do with gas pressure.

Email Pentair and ask them if it's ok to run a 400,000 btu/hr heater on a 250 cubic foot per hour meter.

I suspect that they will say no.

The person on the phone isn't going to be an engineer or technician.

The person answering an email is going to be much more qualified because if they don't know they will forward it to someone who does.

And, it's in writing, so they will be more careful to get the right answer.

In my opinion, there's no way that they will tell you that running the heater on that meter is acceptable.

Note: Safety switches and sensors are backup and not intended to replace proper installation or to verify proper installation.

It's like someone installing a gas appliance in your home where it's clear that they didn't do it right and they tell you not to worry about it because the smoke detector will let you know if it's not working properly.

Maybe I'm missing something, but it seems clear to me that if something is rated for a load of X, then you don't apply a load of 1.1X or 1.6X or 2X.
 
JamesW said:
The heater doesn't have any way to sense the gas pressure and automatically shut off if the gas pressure is too low or too high.

If it did, there would be an error code or light for gas pressure out of range, but there's no such thing.

It does have a sensor that detects the flame. If the flame is significantly degraded, it might shut off the heater, but it's not a good idea to run like that.

There is a water pressure switch that detects water pressure, which is a proxy for a flow switch, but it has nothing to do with gas pressure.

Email Pentair and ask them if it's ok to run a 400,000 btu/hr heater on a 250 cubic foot per hour meter.

I suspect that they will say no.

The person on the phone isn't going to be an engineer or technician.

The person answering an email is going to be much more qualified because if they don't know they will forward it to someone who does.

And, it's in writing, so they will be more careful to get the right answer.

In my opinion, there's no way that they will tell you that running the heater on that meter is acceptable.

Note: Safety switches and sensors are backup and not intended to replace proper installation or to verify proper installation.

It's like someone installing a gas appliance in your home where it's clear that they didn't do it right and they tell you not to worry about it because the smoke detector will let you know if it's not working properly.

Maybe I'm missing something, but it seems clear to me that if something is rated for a load of X, then you don't apply a load of 1.1X or 1.6X or 2X.
Click to expand...

Amen !!! Most safety switches/devices are to prevent catastrophic events, but in allowing an appliance to operate in pre-alarm triggering modes is not a way to treat your equipment.

I have always been a huge advocate of "getting things in writing from a qualified man rep". There's no refuting later and when they stick their neck out, you can count on it being correct, which is the information you need.

If I have 400K BTU requirement, I am not going w a 250/260K regulator. Also, I am not an advocate of turning off one appliance to make sure that another appliance can obtain the correct amt of a resource. To rob Peter to pay Paul has never been a good strategy, esp when you are dealing w natural gas.

If you do the upgrade, it's a one time charge and you are done and have both peace of mind and the correct spec's...good luck
 
Just to be safe, I didn't run the heater besides that first time when the plumber tested it

Centerpoint called me this morning and I was glad that I had done a bunch of research. Instead of just telling them to upgrade my service, I explained all the equipment that I have and asked if they have to increase the line pressure to 2psi or if they also have larger volume meters at the existing low household pressure (0.25 psi). She then told me that upgrading the meter only for more volume at the current pressure is completely free of charge.

They only charge $350 when they have to change the meter to 2psi pressure and put in regulators further downstream to bring the pressure back to the typical 7" wc (=0.25 psi) the appliances use. Since the line from my meter to the gas heater is only 10ft and the heater is already running with the current meter, they said it will probably be enough to only switch the meter for more volume without increasing the pressure.

Apparently the reason why sometimes higher pressure is required is when the meter is far from the pool heater and the plumber does not want to put in a large diameter gas line. Instead of putting in the huge diameter gas line, they upgrade the pressure at the meter. Then they can continue that high pressure underground through a small diameter gas line all the way to the pool heater and reduce the pressure again with a regulator right in front of the pool heater.

Does that sound right?
 

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