Temperature variance on my Hot Spring Aria

[rurimaja]

So, since I got my Hot Spring Aria a few weeks ago as reported here - which I generally think is a very nice product - the temperature of the actual water is always 2 if not 3 degrees higher than what you set it for.  More so, what the display is reading as the current water temperature is never the same as what the actual water temperature is (usually off by about 2 degrees).  My dealer has been out twice to fix it - with no change.  He referred me to their customer service (Watkins Mfg) who told me it's normal to be off by up to 2 degrees at a time. I argued that it was okay if the actual temperature was off from the set temperature by 2 degrees, but that regardless of that, what the display says should ALWAYS be accurate. My biggest concern being that I don't want my kids going into 104-degree water (which is what it's at when you set it to 101 or 102 degrees). Am I crazy to think this is nonsense that a $12K hot tub should have an accurate temperature reading ... or am I over reacting?

[d00nut]

More so, what the display is reading as the current water temperature is never the same as what the actual water temperature is (usually off by about 2 degrees). 

How are you confirming this? 

Hot Spring spas have a 2 degree variance with their temperature.  So I tell people to set it lower by 1 degree or so than what you want, especially in the summer.  Unlike Jacuzzi, and other brands, the Hot Spring never shuts off the circulation pump, so it tends to get a bit warmer.  The cover also gets super hot, which contributes to the heat of the tub.

The readout on the screen should be the current temperature of the spa.  If you are using one of those dinky floating thermometers to test it, I would trust the digital over those things. 

[Chas]

If your tub is holding a steady temperature, and that temperature is comfortable for you, then it shouldn't really matter what the numbers on the display are saying. I know it would be nice if the numbers lined up with reality perfectly, but they most likely will be off a degree or two. The same temp sensor which tells the computer when to start and stop the heater is telling the display what temp to tell you the water is, so if you have to set the tub for 102 to get 103, keep in mind that it's going to SAY 102 when the water is really 103 (or whatever). Now as I said, if the water STAYS at 103 reliably, then you're good.

Before all of our tubs went digital, we had knobs. You turned them clockwise for warmer, and counter-clockwise for cooler. The scale behind those knobs were usually marked in just colors from blue to red, or some were labled "warm" and "hot," or even "warmer =>" And if you wanted it warmer, you could figure out what to do.

If the tub is NOT holding a steady temperature, and all pool thermostats are junk and should not be used in this application, then you have a problem. Again, if you can comfortably sit in the water, and it feels fine night after night, then you're good. If the water temp is actually climbing, and again I urge you NOT to trust a pool thermometer, then you could try the summer timer. That is a system which shuts off the circ pump for eight hours a day. You go out and turn on "Summer Timer" at the start of the warm part of the day in your location. Eight hours later it comes back on, and will repeat that until you shut it off. That stops the small trickle of heat that the circ pump bleeds into the water - and it is a VERY small trickle. But due to the fact that your tub is very well insulated and has a nice new cover, it can add up if it happens to be very warm in your area right now, and if you don't open the lid for days and days at a time.

Thermometers which are super accurate are super expensive. Here's a link to see some electronic ones: http://techinstrumentation.com/categories.php?category=Thermometers/Precision-%252d-High-Accuracy-Thermometers&gclid=CJOawqrS37ACFY4FRQodXHaE1Q

The key to a good glass thermometer is that the markings have to be on the glass, not on a card behind the glass. I have made countless service calls over the years which revolved around "wild temperature swings." I got there, put in my "real spa technician thermometer," and the water was 102. I pulled out their pool thermometer, showed it them at 99, then tapped it lightly on top, and then showed them 103, then tapped the bottom, and showed them 90 or so again.

Here's a thermometer from Amazon for less than $5:


HTH

 

[rurimaja]

Thanks Chas.

I had a feeling the floating thermometer was junk, so I've been actually testing it with a digital thermometer (oral kind used for checking a kid's temperature).  What the temperature on the thermometer says rarely, if ever, is the same as what the reading on the display says.  Nor is it what I've set the temperature to be.  Hence my frustration. So now I've set the temperature to 100-degrees, the readout says 102 or 103 (fluctuates), and the actual temperature is sometimes 104, but seems to be where I want it - 102 - most of the time. 

Again, if the readout where simply accurate recording of what the actual temperate was, I'd be cool with that.

I gave the Watkins rep an earful.  Let's see what happens!

[Chas]

The two spas I have running on my showroom floor do climb a bit - I have them set for 102 and they will climb to 104 if we have a slow week and don't open the covers. We do check the chems every Friday, even if they haven't been opened all week, and that's the time they are likely to have climbed to 104. But after leaving the lids open to breathe (adding chlorine) for a few hours (also to wipe down the shell and the lid) they will usually be right back on the spot. If we open them every day, even for a brief period of time (remember before the economy hit the skids?) they are always at a constant temp: no climbing.

I have not checked with a thermometer - but I think mine are both off one degree. No joke: I can tell the temp with my hand by now.

HTH