JXI Jandy - max heat 100?

[PoolGate]

My pool is 91. I want to get it up to 95. The heated water coming out of the returns is barely 96. Does this heater have a max? There is a thermostat in it does that open more when it gets hotter to bypass some water?

 

[ajw22]

Your heater has a max temperature set by the limit sensors which is likely 104F.

What is your air temperature?

Your heater put a fixed BTU of heat out. But without a pool cover the BTUs out can all be lost to the outside air.

I find that I cannot get my pool heated more than about 10 to 15 degrees above the air temperature. When the delta is greater the heater will run and the water will not get hotter.

 

[PoolGate]

I checked this morning and got the following:

Air Temp 69
Pool Temp 83
Water Temp coming from heater 88

I think I should be getting greater than 5 degree rise. Would a stuck open TRV (thermal regulator valve) cause this?

Pool just seems really slow to heat I am used to a solid 1-2 degrees per hour.

 

[PoolGate]

I read the comments on the TRV that I put in. I did not use an OEM part. Many of the comments say this valve is junk and failed very quickly. Most are saying it doesn't open when it should. That it is closer to 160 before it opens and some said it didn't open at all. Wouldn't that make the water coming out of the returns hotter? Could the bypass poppet have anything to do with it?

 

[PoolGate]

So here I am at 11:22 and water temp is now 88. So I guess it's working ok.

 

[ajw22]

Your heater gives a fixed BTU output. The only reason for your heater not putting out its rated BTUs is low gas pressure and not getting the necessary gas flow.

If you are burning 4CFM/hour of gas, which you can confirm by monitoring your gas meter, then the heat is either going into the water or out the exhaust. You can measure your exhaust gas temperature using an infrared thermometer.

88-90 is about the maximum I would think you can get the water up to with 69F air temperature. As the air temperature warms up into the afternoon you may pickup a few more degrees.

 

[PoolGate]

Your heater gives a fixed BTU output. The only reason for your heater not putting out its rated BTUs is low gas pressure and not getting the necessary gas flow.

If you are burning 4CFM/hour of gas, which you can confirm by monitoring your gas meter, then the heat is either going into the water or out the exhaust. You can measure your exhaust gas temperature using an infrared thermometer.

88-90 is about the maximum I would think you can get the water up to with 69F air temperature. As the air temperature warms up into the afternoon you may pickup a few more degrees.

What temperature should the exhaust gas be?

 

[ajw22]

What temperature should the exhaust gas be?

Here is what the normal exhaust temperature on the Pentair MasterTemp should be. I would figure your JXI should be similar…

• Below 250 degrees...very low
• 250 to 290 ..................low
• 290 to 350.................acceptable
• 350 to 480 ..................high
• Above 480...................error/shutdown.

Note: HD models can be up to 75 degrees higher. HD models use a cupro nickel exchanger and the efficiency is slightly lower resulting in less heat transfer and more waste heat.

If the exhaust gas temperature is higher then normal then water may be bypassing the heat exchanger through a broken bypass valve.

 

[ajw22]

This is what I get on my MasterTemp…

 

[PoolGate]

Hmm... The highest reading I get on the exhaust is 245. What does that mean? Gas pressure is too low?

 

[ajw22]

Hmm... The highest reading I get on the exhaust is 245. What does that mean? Gas pressure is too low?

That means you are not losing BTUs out the exhaust.

If your heater uses 4CFM/hour of gas then your heater is putting the rated amount of BTUs into the water.

 

[PoolGate]

That means you are not losing BTUs out the exhaust.

If your heater uses 4CFM/hour of gas then your heater is putting the rated amount of BTUs into the water.

Ah ok sweet so this means it is efficient and not wasting heat out the stack. It did well this weekend. I got the pool up to 92.