New tub... curious heating on initial run. HOT SPRING ?

[dougga]

Hi, I just received a new tub and filled it with 65 degree water.
I ran it for two hours and the temp was 67, for 1 degree F per hour.
2 hours after that, the temp was 70, for 1.5 degrees F per hour.
1:45 after that the temp was 83, for 7.43 degrees F per hour.

This seems very strange.

Configuration:
Brand: Hot Spring
Model: Bolt
Power:  230v  50a
Heater:  6000w for the 230v model 
             1500w for the 120v model
Capacity: 290 gal


It was sold to me as new, yet the electrician told me it appeared that this was a floor model because there was a 120v outlet installed within the tub itself and this isn't done on a 230v install.

The question I have is really perhaps three-fold. 

1)  Am I really getting 6000w of heating or did I somehow get a tub with inferior heating. 
2)  The heating is strange as it goes from 1 degree per hour to almost 8 per hour.  What could this be about?
3)  How can I tell if I got a used tub?  The dealer said nothing about selling me a floor model.

Thanks in advanced for your help.
Cheers!

[d00nut]

A bolt has a circ pump, and the circ pump is running 24/7.  The circ pump line is the only one that goes through the heater.

If you are running your jet pump (it just sounds like you are) that is actually not helping it heat faster.

Now when you go 230 V, the heater and the jet pump should run concurrently, but if your electrician or dealer didn't configure the soft jumpers, it won't run concurrently (this is what sounds like is your problem)

I sell that spa, it comes standard from the factory with a 15ft GFCI plug.  That should have nothing to do with it being a used tub.

Try leaving the jets off.  I am sure it will heat faster.  Then contact your dealer to get the soft jumpers set correctly. 

Hope this helps!

[dougga]

Thanks for the update.
Ok, I put on my coke bottle glasses and went into high nerd mode.

Code: [Select]

Time F Hours F change  F/h C/hour   c/h         c/s     watts
1:00 PM 65
3:00 PM 67 2:00 2 1.00 610 609,870 169     709
5:00 PM 70 2:00 3 1.50 915 914,805 254     1063
6:45 PM 83 1:45 13 7.43 4530 4,530,463 1258     5265
8:52 PM 100 2:07 17 8.03 4898 4,898,169 1361     5693

The effective heating of the tub is all over the place.  The last column is the number of watts of energy that are transmitted to the water on average based on the temperature difference and the quantity of water.  For the quantity I used the capacity but didn't fill the tub to the brim so this number may be off.  It's not clear to me what 290 gallons would look like in this tub.  Anyway, that doesn't matter.  What does matter is the tub went from 709 watts of heating to 5600 watts. 

Note: The jets were on, but only from 4 - 5pm.  Even if the jumpers were set wrong, it wouldn't effect the period I have between 1 - 3pm which showed the lowest heating of 709 watts.  Even the 110v model is rated at 1500 watts.

That's really strange, isn't it?  Since the heater is rated at 6000 watts, and it's impossible to show 100% efficiency in a heater, around 5700 watts sounds about right. 

I'm just curious what's going on.  Why did it take 4 hours or so before the heater functioned at anything near capacity?

Thanks again.

[dougga]

Update: 

The tub's maiden voyage was excellent!  I'm going to love this thing.   

Now, there was something interesting that suggests that it's not setup correctly.
The salesperson emphatically stated that the 230v model will heat while the jets are on.
This is a 230v system but doesn't heat when the jets are on.  In fact, it's quite clear that
the heat is turned off the moment the jets are activated.

I've found the detailed installation instructions and will review the current configuration in the am.
Owner's Manual: http://www.hotspring.com/sites/default/files/Limelight_Collection_2015_Owners_Manual.pdf
See page 29: "230 Volt Converted Bolt"


Thx.

[wmccall]

Doug,

Welcome to our forum.

You may be right, it does sound like a configuration issue. There are several other HS experts here, they should be along shortly.  I modified the subject of your message to make sure they see it.

[dougga]

Pretty quiet, but thanks.

[dougga]

I had a hilarious conversation with the Hot Tub Technician at my retailer.

I told him about the slow heating and he informed me that water heats more slowly at cold temperatures.
Being a former laboratory biochemists I decided to make sure I understood him correctly.

I explained the recordings and calculations I made above and he confirmed:
Water behaves differently at different temperatures.  It's not that the universal constant of a calorie can be defined by the amount of energy it takes one ml of water to be raised one degree Celsius.  He was informing me of a whole new physics where at lower temperatures, it takes more energy to raise it one degree Celsius.

You heard it here first.  It should reach the physics scientific publications first then perhaps to the New York Times in a year or so. 
Yet another argument for STEM education in high school.

Heh...

[dougga]

Another update.

The hot tub service guy indicated the tub needed a "software update" to tell it it was running on 230v.

At this point, I don't believe a word these people say, but they are coming out to do this update.
I assume they wish to fix their botched install and are just making up stuff to look like they know what's going on.

[hottubdan]

It could in fact need an update.  If the 110v cord was still attached at delivery, then your electrician had to do the conversion.  Might have been his "botched install."

What is serial #?  That would tell year of spa.  When it was delivered, was it packaged?

[d00nut]

I'm pretty sure it has to be the soft jumpers.  On 220V, that thing should heat fast.

Did they actually deliver it and fill it?  Or was the electrical not done at the time of delivery?  There is a software button on the interior of the IQ 2020 (spa control box) that allows you to configure the soft jumpers when pressed.  Although, I wouldn't really recommend you yourself doing it, as I believe the dealer should. 

Let me know what happens and if you need some more help, perhaps I can help you from afar.

[Dr. Spa™ Ret.]

So Newton's Law of Cooling is wrong?

[dougga]

Ok, I'm not going to review high school chemistry.
No, Newton's law of cooling is not wrong, it's just not relevant here.
So who exactly gave you that doctorate?  In poetry?

Newton's Law of Cooling  states that the rate of heat loss of a body is
proportional to the difference in temperatures between the body and
its surroundings while under the effects of a breeze.

This is not related to too different temperatures, this is a hot tub full of
water that's extremely well insulated.  This issue revolves fairly closely around
the first law of thermodynamics.

Here's a little video to help: https://www.youtube.com/watch?v=h-31O7CaF2o
Here's more people explainging this: https://www.reddit.com/r/askscience/comments/13np3r/hot_tub_heating_linear/