temperature is 108 F -- is this normal??

[knightcap]

I've had a new hot tub since Nov 2006, so I've never had it in the summer.  The other night, I had it set for 100 degrees, and the temperature of the water rose to 108 degrees.  This is what the digital readout said, and I double-checked it with my pool thermometer.  It was so hot I couldn't even get in.  I live in St. Louis, and it was 80-85 degrees for a couple days before.

My jets run for 20 minutes, then turn off automatically.  I ran both pumps about 3-4 times in a row, so about 60-80 minutes (trying to filter the water, it was cloudy).  I called the dealer today, they didn't really want to send anyone over until Tuesday, after the holiday.  He told me this was normal -- that in hot weather, just running the pumps can build up so much heat to warm the water.  He suggested I put a softball under the cover to vent in -- prop it open a couple inches.

I suspect the heater is turning on anytime the pumps are on, even though the "heater light" does not tunr on.  So my questions for you fine, knowledgable folks:

1. can a hot tub heat to 108 degrees simply by running the jets, with the heater set to 100 degrees?

2. is there a way for me to check if the heater is turned on and heating the water, when the light on the control panel is not on?

3. any other reasons why it would get this hot?

Thanks!!

[hottubdan]

Is the hot tub in direct sun?

What brand spa do you have?  How is it insulated?

It is possible/probable that running the pumps with the cover on as long as you did elevated the temp.

[loosenupspas]

check the spas programing, doubling checking your filtration durations and the spas clock.  like a car with its windows rolled up, a spa creates its own heat which is trapped inside the cover and is recirculated in the water without a way to escape.  you could try to raise a corner or two to ventilate the trapped heat.  pumps running excessively will cause thermal-creep in the water temperture.  you cannot rule out a problem with the heaters thermostat.  good luck

[knightcap]

Thanks for the replies.  Some answers:

The tub is an Alexa, by Outback.  I think it is made by a bigger company -- maybe Hot Springs?  When I remove the skirt, the insulation is sprayed on to the underside of the tub.

It does sit in direct sunlight -- south side of my house, no trees at all for shade.  (BTW, I'm using 303 on the cover, hoping that helps.)

The dealer (Prestige Pools in St. Louis) also said that the pumps themselves could be building up heat and heating the water.  He said they have a lot of overheating problems with hot tubs in the summer.  Does this sound right?

I did try venting the cover, by propping it open a couple inches.  This brought down the temperature.

Is there any way for me to check the termostsat, or does this take a qualified service person?

[Gary]

Unless you are running very long filter cycles I think you have a problem. Do not let Fran give you a hard time over there, tell them they need to come look a it.

[webboy]

This might help.

http://www.whatsthebest-hottub.com/cgi-bin/yabb/YaBB.pl?num=1179812432

This discussion was just last week.

Good luck