Can I Run Jandy JXI on 100lb tank?

[gnr5]

Hello,
So I had a Jandy tech come out and after multiple test, they realize my old 1995 500gal propane tank is shut. I have to replace it. I don't run anything else on that tank other than this pool heater. Would it be possible to run this pool heater on one (or two) 120lb tank? We're in South Florida so really only use the heater about a month or two.

Thanks!

 

[ajw22]

What size JXI heater are we discussing?

How many gallons in your pool?

A 100 lb propane tank has about 2,000,000 BTUs.

That has enough gas for a 400,000 BTU heater to run about 4 hours. That is probably not going to heat your pool very much depending on its size.

 

[gnr5]

Our pool is 10,000 gallons, we're looking to mostly heat up our Spa which is likely 800g at most.
Heater is JXI400P

 

[ajw22]

You should get around 200 degrees of heat in your spa.

 

[gnr5]

I'm going to try to hook it up and see how much time i get out of that tank. Right now I have a first stage, and second stage regulator because I'm connected to the the 500gal tank. If I were to switch to the 100lb, do I still need those regulators?

 

[ajw22]

I'm going to try to hook it up and see how much time i get out of that tank. Right now I have a first stage, and second stage regulator because I'm connected to the the 500gal tank. If I were to switch to the 100lb, do I still need those regulators?

I suggest you consult with a gas tech and check the gas pressure at the heater gas valve with a manometer on any setup change.

 

[1poolman1]

Hello,
So I had a Jandy tech come out and after multiple test, they realize my old 1995 500gal propane tank is shut. I have to replace it. I don't run anything else on that tank other than this pool heater. Would it be possible to run this pool heater on one (or two) 120lb tank? We're in South Florida so really only use the heater about a month or two.

Thanks!

A JXi 200 will use about 2 gallons an hour. A 260 will use about 2.6 gallons an hour. A 400 will use 4 gallons an hour. A 100lb. tank has about 23 gallons in it when full.
That size tank is used for a cooktop, temporary heat, not pool heating. It will go quickly and when the tank starts to run low it can cause issues with the heater.

 

[JamesW]

If I were to switch to the 100lb, do I still need those regulators?

Yes, the pressure is the same.

Understanding the propane capacity of a 100 lb tank is essential for proper usage and safe storage.

A 100 lb tank holds approximately 23.6 gallons of propane, but due to safety considerations, only 18.9 to 20 gallons are usable.

100 lb tanks are 4 feet tall and about 20″ in diameter.

 

[JamesW]

___________________________________________________________________________________________

https://www.marshallexcelsior.com/sites/default/files/LPGServiceHandbook.pdf

https://www.mulherngas.com/PDFs/NYPropaneGuide.pdf

 

[JamesW]

Would it be possible to run this pool heater on one (or two) 120lb tank?

Basically, no.

The vaporization rate depends on the ambient temperature and the amount of wetted metal wall.

The propane needs to boil from the heat in the air making contact with the metal walls of the cylinder where liquid propane is on the opposite side of the wall.

If you try to draw too much gas, the propane cannot convert from liquid to gas fast enough.

 

[JamesW]

The capacity to deliver gas at the correct rate depends on multiple factors including if the draw is intermittent or continuous, air temp, humidity, tank size, fill level etc.

Even the term intermittent is not well defined.

Does this mean a percentage of time on vs. off or maximum continuous time or both?

In any case, small tanks are not going to be able to deliver 400,000 btu/hr.

 

[JamesW]

VAPORIZATION RATES FOR ASME STORAGE TANKS.

A number of assumptions were made in calculating the BTU figures listed in the Table 4 below:

1) The tank is one-half full.

2) Relative humidity is 70%.

3) The tank is under intermittent loading.

Although none of these conditions may apply, Table 4 can still serve as a good rule-of-thumb in estimating what a particular tank
size will be provided under various temperatures.

Continuous loading is not a very common occurrence on domestic installations, but under continuous loading, the withdrawal rates in Table 4 should be multiplied by 0.25.


VAPORIZATION RATES FOR 100 LBS / 45 KG DOT CYLINDERS.

“Rule of Thumb” Guide.

For continuous draws, where temperatures may reach 0°F / -18°C, assume the vaporization rate of a 100 lbs / 45 kg cylinder to be
approximately 50,000 BTU/hr.

Therefore the: Number of cylinders per side = total load in BTU/hr / 50,000.

https://www.emerson.com/documents/automation/lp-10-handbook-en-us-8439918.pdf

 

[JamesW]

Different references can give different rates.

For example, below shows 94,000 btu/hr at 40 F at 100 lbs and a different reference shows 214,000 btu/hr for the same temp and 100 lbs.

That is a difference of 2.28 times.

I suspect that the higher number is probably inaccurate and a mistake.

They might have meant to use gallons and not pounds.