Jacuzzi temp control question - how to keep at 104

[richopian]

Hi all you Jacuzzi owners,
I'm loving my j-365 tub; however one thing I am struggling with a bit is temperature control.

I like to have the tub at 104 degrees when I'm in it. Normally I have the tub set to 103 when not in use. Then 15 mins before I want to use it I pop the temp up to 104. The problem is if your in for 20 mins or more with friends, the temp drops right back to 102 (at least I think it does this). I guess the basis for this is that the temp control would have to be always on to keep it at 104 - however this is pretty much what I want when the tub is in use - when not in use I like the idea it will drop down to 102.

Any thoughts - how do you al acontrol the temp. I never thought there would be a big difference but I really like being in at 104.

Let me know how you handle this - maybe I have it wrong and the ttemp is always maintained when in use. I guess I'm just assuming the temp control works the same when either in use of not (drops 2 degrees before the heater comes back on again) -

cheers
Rich

[Gary]

Most likely the heater is coming back on when it is supposed to but if you are having cool ambient temperature the heater will not be able to keep up. There are factors that will cool the water faster and they are: pump in high speed and air being inducted onto the jets.

[richopian]

When the hot tub is in use, does it also let the temp drop 2 degrees before soming back on, or does it try and maintain the temp when the jets are on?

cheers
Rich

[Chad]

Rich,

I have a J-345. 8-)
The heater will kick on only if the water drops 2 degrees below the set temp or if it is already at the set temp and you raise it 2 degrees.
I keep mine at 103 and have one of my programable cycles set to run in the late evening as I soak mainly after dinner. The extra heat from the cycle helps heat the water some. Doing this almost always ensures that the water is at 103 when I'm ready to get in.

[svspa]

I think it's as the other guys stated, with the cover open, etc. the temp will drop. Is your tub wired so that the heater runs when all of the jets are on? If not then in that condition the tub won't recover to the set temp.

You might try running the temp up an hour before using the tub. It might just be barely registering as 104 when you go in, so it drops farther/faster.

When I have compared the display on my j-345 with a thermometer I have found that my display is 1 degree cooler than the actual water temp. So if you set your tub to 104 way before you want to get in maybe you'll actually get closer to 105 and the drop will be less significant.

Steve

[Chad]

When the hot tub is in use, does it also let the temp drop 2 degrees before soming back on?

Yes

[Hammster]

My Sundance is the same way. It has a 2 degree window around the setting. Once it drops 2 degrees below the setpoint, the heater turns on and heats back to the setpoint. One thing I do notice is although I feel the heated water coming into the tub, the temp indication on the tub always lags the temp increase. I mean the water will feel like it's increasing in temperature and a little bit later the temp indication will increase.

[tony]

That is definitely how that controller works.  When the water temp drops two degrees from the set temp, the heater kicks on and shuts off when the set temp is reached.  There is a way to allow the temp to go to 108 on those controllers, but only if its built before 2006.

[Gary]

Sounds like they do have a 2 degree hysteresis, which if you have a pump on heat demand system that would be ideal, but it is kind of old school.

If it bothers you enough I am sure you can special order a board with a lower hysteresis but if  you do that with a pump on heat demand system the pump will cycle more.

[Chad]

Since we're on the topic.
I just got done testing my water's chem levels.
It's 25 degrees outside and I have my tub's set temp at 103. My last programable skimming/heating cycle was at 12:30 pm today. Anyway, my display read 105.
I'm not sure how it got that hot but I'm not complainin'. My tub seems to keep heat in rather well. I guess full foam was the way to go.