Installing a gas heater questions

[youmyboyblue]

Hello!

We have a natural gas pipe already in place where a previous homeowner presumably had a heater.

Pictures attached of the line and equipment in back of the house.

Can the pool heater be put in front of the PVC pipes for the house furnace? This would be the closest to both the gas pipe and the pump/filter.
Also, what kind of clearance is required from the AC and electrical panel?
If this isn't a good spot, we'd have to route the gas line and electrical for the pool heater to the other side of the filter/pump, which is probably doable.
Our outdoor temp. is typically between 60 and 85 F depending on the month.
What size heater is recommended (pool size in comments)? Does it depend on the size of the gas pipe?
I've decided against a heat pump or hybrid unit given our typical usage is more random and not daily.
I assume the pump has to be running when the heater is running? If so I might also upgrade our superpump to a variable pump that's a little quieter (I usually run the pump for 8 hours a day total).
I'm planning on just getting my pool guy to install the heater.

Thank you!

 

[ajw22]

The answer to your installation questions on clearances, gas lines, and electrical are all in the heater installation manual you choose. Since you have Hayward equipment here is a Hayward manual - https://hayward.com/media/akeneo_co...sal_h_series_installation_manual_aus_f50b.pdf

Clearances are on page 11-12. You cannot install a gas heater near windows, doors or air vents.

Gas lines begin on page 15.

There is no substitute for BTUs. The higher the BTU the quicker your pool will heat.

 

[youmyboyblue]

Thank you! I'm thinking we'll go with a 250K BTU unit from Hayward.

Is it typical for a pool contractor to pull permits for this? We have the gas line, but it seems an electrical permit is needed for an "appliance reconnect," similarly a mechanical permit is needed to install the appliance.. I just feel a little more comfortable with the city inspections..

 

[ajw22]

Either the homeowner or contractor can pull the required permits.

Inspectors should be checking the installation meets their codes. They do not check it conforms to the manufacturer installation manual.

 

[BMerrill]

Since the proposed location does not meet the clearances... not sure you can install a heater in the same location again. Contact you local permitting office before proceeding further.
Heater BTU maybe limited by gas line and pressure size.
Permits (Electrical, Gas) should be pulled by the licensed contractors according to their licensure.

 

[youmyboyblue]

Thank you all for the suggestions. I e-mailed my pool contractor about at 250K BTU unit with my concerns about clearances, the gas meter/line/pressure, and permits, and we'll see how it goes.

 

[JamesW]

Mechanical FAQ’s.

1. Can I pull a permit as a homeowner?

a. Yes. Public Act 407 of 2016 states: “An individual who is the owner of a single family dwelling that is, or on completion will become, his or her place of residence may personally install a heating or refrigerating system in the dwelling if the individual in his or her application for a permit affirms that he or she is or will become the owner and occupant of the dwelling in which the installation is done is completed and that the applicant will install the equipment in the dwelling for which the permit is requested.

The applicant shall apply for and secure the required permits from the enforcing agency of the municipality and shall obtain the required inspection after the installation is completed and the equipment is placed in operation.”

5. What license(s) and permits do I need in order to replace a gas water heater?

a. You must have a Michigan Mechanical License with either HVAC Equipment or Gas Piping and Venting classifications AND a Michigan Plumbing Contractor’s License.

A mechanical and a plumbing permit are required for this installation.

https://www.michigan.gov/lara/-/media/Project/Websites/lara/bcc-media/FAQs/Mechanical-FAQs.pdf

https://aatwp.org/wp-content/uploads/2013/10/Mechanical-Permit-Application-4-22-08.pdf

 

[JamesW]

V. Homeowner Affidavit.

I hereby certify the mechanical work described on this permit application shall be installed by myself in my own home in which I am living or about to occupy.

All work shall be installed in accordance with the Michigan Mechanical Code and shall not be enclosed, covered up, or put into operation until it has been inspected and approved by an Ann Arbor Township mechanical inspector.

I will cooperate with the mechanical inspector and assume the responsibility to arrange for required inspections.

 

[JamesW]

The gas line looks pretty small unless it is a 2 psi line.

Do you have 2 psi service or 7" w.c service?

What size is the meter?

The line also looks corroded, so you might need to replace it.

Check the manuals for heater placement as they all have diagrams for acceptable placement and places to not install.

Can you show the writing on this brass valve?

 

[JamesW]

Note: It is recommended that you get a licensed and qualified gas contractor with a Michigan Mechanical License with either HVAC Equipment or Gas Piping and Venting classifications AND a Michigan Plumbing Contractor’s License.

The heater must be installed to all local codes and to all manufacturer's instructions.

You should register the heater with the manufacturer when it is installed.

If the heater is not installed by a licensed contractor, then you will probably not get the full warranty.

The installation will require a permit and an inspection.

If the heater is located under a roof overhang, there must be at least three (3) feet (1m) of clearance between the bottom of the overhang and the top of the heater exhaust vent, see Figure 8.

If the heater is under a roof overhang, the space around the heater must be open on three sides.

DO NOT, under any circumstances, install the heater under ANY deck.

Locating the heater:

Locate the pool/spa/hot tub heater in an area where leakage of the heat exchanger or connections will not result in damage to the area adjacent to the heater or to the structure.

When such locations cannot be avoided, it is recommended that a suitable drain pan, with drain outlet, be installed under the heater.

The pan must not restrict airflow.

This heater must be installed at least (5) feet from the inside wall of a pool (in-ground or above-ground)/spa/hot tub unless separated from the pool/spa/hot tub by a solid barrier.

The heater must be installed such that the location of the exhaust gas vent assembly outlet relative to adjacent public walkways, adjacent buildings, openable windows, and building openings complies with the National Fuel Gas Code (ANSI Z223.1/NFPA 54) and/or CAN/CGA B149 installation codes.

Outdoor installation and service clearances:

The heater must be installed outdoors such that the installation and service clearances from combustible materials shown in Table 2 are maintained.

1. The heater is self-venting when installed outdoors and does not require additional vent piping.

2. Do not install in a location where growing shrubs may in time obstruct a heater’s combustion air and venting areas.

3. Do not install this appliance under an overhang less than (3) feet from the top of the appliance.

The area under the overhang must be open on (3) sides.

4. Do not install the heater where water spray from ground sprinkler can contact the heater.

The water could splash on the controls causing electrical damage.

5. Do not install under a deck.

 

[youmyboyblue]

Thank you all for the help!

I was referred my my pool contractor to another licensed contractor who specializes in pool heaters, outdoor gas feature installs, gas lines, etc. and will pull permits. He hasn't come out in person yet but thinks the clearances can be met based on some pictures I've sent.

Do you have 2 psi service or 7" w.c service?

What size is the meter?

The line also looks corroded, so you might need to replace it.

The line for the pool heater is 1". It comes off of a larger line inside of the house that goes to the furnace and water heater. I've attached a picture of the valve. The gas meter says 5 PSI, picture also attached. The house is 16' from the pool, so seems the 4' we need from the house and 5' from the pool edge can be met, plus 3' clearance from the house furnace intake pipe.

Any suggestions on a Hayward unit?

Thanks again for the help!

 

[JamesW]

I suspect that you will need a new meter and a new gas line.

It looks like you should be able to meet the required clearances.

You have a “250” Class Meter, which means that is will pass 250 CFH (Cubic Feet per Hour) at a pressure drop of 1/2” w.c (Water Column).

It can do more at higher pressure drops.

For example, it might do (sqrt2 x 250) = 353 CFH at 1” w.c drop.

You can use a 1” w.c drop if you compensate by increasing the pressure before the meter by 0.5” w.c.

To properly size the meter, you need to know the total maximum load that could run at the same time and then size the meter based on a 0.5” w.c drop or a 1” drop if the utility chooses to use a 1” w.c drop.

The meter will be rated by the manufacturer at different pressure drops.

The line size depends on the length, CFH and pressure and the heater manual will give the proper line sizes.

The NFPA ANSI Z223.1 National Fuel Gas Code also gives line sizing information.

https://hayward.com//media/akeneo_connector/asset_files/U/H/UHS_Service_Installation_011717_RevT_6fd9.pdf

 

[JamesW]

The gas meter says 5 PSI, picture also attached.

5 psi is the MAOP (Maximum Allowable Operating Pressure).

That just tells you the maximum pressure that the meter can handle.

It does not tell you the actual pressure that is being used.

Service will either be 7" w.c or 2 psi.

If you have 2 psi, you will have a regulator after the meter and before the appliances/equipment to lower the pressure to 7" w.c, which is what most appliances use.

If there is no regulator between the meter and the appliances, then you probably have 7" w.c (low pressure).

There will be a regulator before the meter that will have a stamp of 7" w.c or 2 psi on the regulator to indicate which pressure you have.

 

[youmyboyblue]

Thank you so much, JamesW! This is all new to me and I love learning about it.

I took a good look at the gas meter. Pic attached. Unless it's somehow built into the meter, I can't find a regulator before the meter.

In the basement near where the meter line comes in, on the ceiling, there is a "mystery box" as I've always called it hahhhha. I've always wondered what it is. A previous homeowner sealed pretty well in a couple layers of wood, I presume due to aesthetics (they "finished" the basement). Due to my tinkering nature I once started taking off the wood to see what it is, but I hit a wood layer with nails and decided not to pry it apart any further. This is probably the regulator between the meter and the appliances. I haven't seen regulators "downstream" closer to the appliances.

The inside gas line looks larger than 1". I'll need to check that. The "branches" to the appliances look smaller. I don't think it's more than 50' from the meter to the appliances, including the pool heater line.

The three gas appliances we currently have are:
Furnace: 100K BTU
Normal tank water heater: 35K BTU
Gas dryer: 35K BTU

So 170K BTU total. According to "the google,' the 250 CFH capacity can be multiplied by 1000 to approximate the BTU "load." So yeah.. guess this meter would barely handle the pool heater by itself, unless the 1" drop is used, then it looks like 353K would be the max? So then a 150K pool heater could be used.. but a unit this small might be overworked/take longer.

More details to be analyzed for sure but this is a great starting point. Thanks again!

 

[JamesW]

Most likely, the meter will need to be replaced with a larger meter.

The utility does this all the time and it is not a big deal.

Contact them to request a new meter and they will tell you the procedure.

Some utilities charge a fee and some don't.

They can figure out the regulator issue.

You need a qualified licensed gas contractor to evaluate the existing lines and determine what the proper plumbing should be.

For the new meter, I would use 400 CFH for the new heater for planning purposes.

That puts the total at about 570 cfh.

You can use a 400 class meter with a 1" wc pressure drop up to 565 cfh or a 630 cfh class meter with a 0.5" wc pressure drop.

The utility can determine the correct meter based on the total load.

Meters can be used up to a pressure drop of up to 2" wc if the pressure before the regulator can be increased to 9" so that the pressure after the meter is 7", but I would not go above 1" wc pressure drop.

 

[JamesW]

You have a regulator; it is the round disk with the cylinder sticking up.

The pressure should be stamped on the top of the cylinder.

 

[JamesW]

The device in the red box is a regulator.

The regulator should be stamped with the pressure somewhere on the regulator.

The red arrow points to the vent.

The vent should be pointing down to keep rain out of the regulator.

Yours is pointing horizontally.

 

[JamesW]

You will need a new regulator and a new meter for a new heater.

You can use a "425" class or a "630" class meter.

The 425 class meter will be rated in the 425 (0.5" w.c pressure drop) to 583 CFH (1.0" w.c pressure drop) range.

The 425 class can be used up to about 898 SCFH if you allow for a 2" pressure drop.

If you go over 425 CFH, you can increase the regulator to 8" or 9" w.c before the meter to account for the higher pressure drop.

The 630 class meter will be rated in the 630 (0.5" w.c pressure drop) to 900 CFH (1.0" w.c pressure drop) range.

Meters are sized partly by the pressure drop.

For example, the AL-425 can deliver different flow volume based on the allowable pressure drop.

The meter will deliver 425 CFH at a 0.5" pressure drop.

The meter will deliver 583 CFH at a 1.0" pressure drop.

If you allow for a 1.5" pressure drop, the meter will provide about 740 CFH.

If you allow a 2" pressure drop, the meter will provide 898 CFH.

https://cdn.shopify.com/s/files/1/0726/8799/files/AC630.pdf

American Meter-AC630 Diaphragm Gas Meter (630,000 BTU/hour)

A multipurpose diaphragm gas meter capable of gas loads up to 630 MBH (0.6 SG Gas @ 7" WC). Our standard stock configurations come with 1-1/4" connections IN STOCK! Product Description: The Honeywell American Meter AC630 is a diaphragm gas meter with an odometer index that registers gas volume...

mcsmeters.com

Some gas companies use the 0.5" w.c pressure drop rating, which is conservative and some use the 1" pressure drop rating.

If your pressure before the meter is 7" and you have a 1" drop, then your pressure out of the meter is 6" and then you have a 0.5" w.c pressure drop through the gas line, which leaves you 5.5" w.c.

400K BTU Gas Heater - Need Help with Meter Upgrade

Well we are finally in the middle of our pool build with shotcrete getting done earlier this week. The next step is to run the needed utilities for the equipment which I thought would be one of the easier steps in this build. We will have a Pentair 400K BTU gas heater as part of the build. I...

www.troublefreepool.com

 

[JamesW]

Your current meter is an AC250.
The AC250 is good for
250 CFH at 0.5" wc drop or
355 CFH at a 1" wc drop or
460 at a 1.5" wc pressure drop or
565 CFH at a 2" drop.

I would not go more than a 1" wc pressure drop for sizing a meter.

Most likely a 425 class meter will be ok.

The 630 class might be preferable if you need a 0.5" maximum pressure drop.

 

[youmyboyblue]

Thanks again for the help. Here is where I'm at..

The pool heater installer will pull permits. I tried to ask him about the gas line and meter sizing and sent him pictures, but his reply is along the lines of, "There was a pool heater installed previously, so what you have for the meter and pipe is probably OK."

I've contacted the natural gas company about adding the 250K pool heater and got the ball rolling for a probable service upgrade.

I'm looking to sanity check the gas line that goes through the house to the pool heater. The 1.25" gas line seems to be OK based on my novice understanding.. is there anything I'm missing?

• The gas meter regulator is 7" WC = ~0.25 PSI (low pressure).
• The total line length from meter to pool heater is ~56'. It's a copper line, 1.25" outside diameter. The last ~5' where it "T's off" is 1".
• Based on Table 10 above, 1.25" diameter for this distance (50-100') is sufficient for a 250K BTU pool heater.
• Based on Table 6.2.1 (b) above, the gas line provides ~528 cubic feet of gas per hour (rounding up to 60' length). The line has a 100K BTU furnace which requires ~91 cubic feet of gas per hour and the pool heater will is 250K BTU which requires ~225 cubic feet of gas per hour. So this line will have ~316 cubic feet of gas per hour total on it, which is under the limit.

Rough diagram of the house's natural gas setup below.. there is a 1.25" line for the furnace and pool heater and a 1" line for the dryer and water heater.