Hot Tub Forum
Original => Hot Tub Forum => Topic started by: Bigbender on June 29, 2005, 01:08:49 pm
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I'm sure that you don't hear this comment too often but now that hot weather is here in Pa. (90's), we're having a problem keeping the heat "out of the water". We turned the temperature setting back for the summer so the water could cool us off but the circulation pumps are creating enough heat on their own that they've actually increased the water temp to 105 degrees.
I sure don't want to sound like I'm complaining about the efficiency of the insulation because it saves me a lot of heater time during the winter months but I believe this may be a slight dis-advantage to the Thermolock™ Technology used in the Coleman tubs. I don't want to cut back on the circulation settings so I guess I'll lift the lid and have it open like a swimming pool.
Do they sell diving boards for these things :)
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Ok so your tub has the thermo lock by coleman, so does it have a standard, sleep and economy mode? cause I was told if you put it on economy mode the heater will only operate during filtration cycles and the pump will circulate approx. two min several times throughout the day to sample the water.
Hope this helps
Backpains
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I had the same problem with my HS Envoy the water got to 106 degrees. I put a water bottle under each corner of the cover to hold it open a few inches and it brought the temp down to 101 in 10hrs
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From what I read in the Sundance manual, it (Maxxus, even though I don't have one yet, sigh...) has the economy/summer mode, also. This one appears to be automatic: if the water gets hot enough, it will switch off the circ pump and ozonator except for a 2 hour filtrator daily filtrator cycle to reduce heat input.
Anyway, same thing as the previous post: You can use a summer/economy mode to reduce heat input, or open the cover to increase heat loss; other suggestions I've seen here are to insert ice in frozen plastic bottles to get the water to usable temperature levels. I like that answer, since if you want to use it, it's hard/hot when the air temp is 100, the water is the same, and you aren't getting any fun from the spa!
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Bigbender you're right it's nice to hold that heat in, for the 10 months out of the year that we Northerners have winter LOL.
Here are some steps you can do to decrease heat creep.
1. Turn you spa to the sleep mode which will allow it to lose 20 degrees from set temp.
2. Reprogram your filter times to run in the coolest part of the day and evening. For instance your am or first filter could run from 5:00 am to 8:00 or 9:00 am. Your pm or filter two could run from say 10:00 or 11:00pm to 1:00 or 2:00 am or whatever length suits your useage.
3. Tonight let the excess heat off the water by putting a folded towel under the cover. This will create enough of a gap to let the heat escape, and not let every creepy night bug in the area seek out your spa. Make sure you can still fasten your cover should a storm come up.
Hope this helps.
Spahappy :D
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I have my spa set for 98 and it's at 100 and when all the pumps are on, it can hit 101. Tub is only a week old and as Spahappy said - I'm glad it's that efficient for the winter!
Since it has a huge 24 hour circ pump, I guess it's acting as a pump on low speed filtering mode and my summer mode is me turning down the heat to 98.
Look at the bright side - the heater isn't kicking on so look how much money your saving! ;D
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Exactly what vinny said! Mine does the same thing I have it set at 98 and I just got out of it 100 degrees is what it read, but then again I was on a flitration cycle too. Anyway I just throw a couple of bottles of frozen water in, that way hubby and I can have some cold water while we are in the tub too ;D always a plus with the hubby!
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Spahappy,
I read about the mode options in the manual but it doesn't explain the differences very clearly. With my tub set to run in the Standard mode, the circulator pump is running in warm weather without the word "Heat" visible on the control panel so I'm assuming that a thermostat is telling it to stay off. I'm curious as to how the Sleep mode is going to be different ?
Setting the circulator cycles for the cooler time of day settings is a great idea. I'll make that change tomorrow. Is there a trick to keeping clean water with two-four hour circ times? I went from 6-4 during the winter months and before long, my water started giving me problems.
Mike
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If it is in a sunny place, I would bet that most of it is the sun. I own a HS, set the temp for 90 this summer (mini-pool for my 7-year old nephew). After a week Ichecked it and the temp was 100, according to the little floating thermometer we have.
The circ pump is not heating the temp by 10 degrees and the heater is not on.
Propping the cover, or even just taking it off 30 minutes before you get in should help. Even running the pumps for 20-30 minutes should cool it down. With the heater off, the pumps won't generate enough heat to compensate for what you lose out of an uncovered tub.
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Ed
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Not to beat a dead horse, but from an engineering point of view, I have to agree here... with just a circ pump, there is virtually no heat transfer from the pump. But on a summer day, there is a lot of heat 'insolation' (not insulation) added from the rays of the sun beating down on the spa/cover.
You almost wish they had an actual cooling cycle for when it gets as hot as it's been outside, even in Northern Virginia (we've had 90-95 temps for the last month or so, not the usual for May/June!).
I conjecture you are 'expected' to have the spa for the fall and spring (and winter) and a pool with 70 degree water for the 95 degree summer.
;D ;D (Sorry, I don't have the room, money, or muscles for a pool...)
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with just a circ pump, there is virtually no heat transfer from the pump.
Actually, circ pumps running 24/7 add heat to a spa very noticeably. The ones I've seen are very efficient at transferring their heat, which is why the summer timer mode on spas with that setup shut off the circ pump for x hrs/day when people can't get their water temp down to their setpoint.
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The Sundance Laing pump is water cooled, so almost all of the heat it is producing is getting transfered to the water. I heard a figure of 87%, but I have never been able to confirm that. The Sundance "Summer Mode" starts automatically at 95 degrees, so sometimes you can set the tub at 80 and it will maintain 95 just from the circ pump running. Depending on the year, you can adjust the time the circ. pump runs from 2hrs (even at 0, it runs a 2 hr. purge at midnight) all the way to 24hrs. Turning down the circulation pump and reducing the amount of filter time will reduce the amount of heat transfered to the water.
A circulation pump can most defintitely heat the water 10 degrees.
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A circulation pump can most defintitely heat the water 10 degrees.
Many times customers with a circ pump spas have turned their spas on after a refill or at startup and the water heats up to about 80º or so but no further. They assume since it did heat up some that the heater was energized. All along the issue was the heater was not energized and the heating they saw was simply from the circ pump but fooled them and all along they needed to reset their heater or maybe its a spa where the heater has a separate breaker and that has to be reset. Many circ pumps can be VERY efficient at transferring their heat depending on the type used.
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Spahappy,
I read about the mode options in the manual but it doesn't explain the differences very clearly. With my tub set to run in the Standard mode, the circulator pump is running in warm weather without the word "Heat" visible on the control panel so I'm assuming that a thermostat is telling it to stay off. I'm curious as to how the Sleep mode is going to be different ?
Setting the circulator cycles for the cooler time of day settings is a great idea. I'll make that change tomorrow. Is there a trick to keeping clean water with two-four hour circ times? I went from 6-4 during the winter months and before long, my water started giving me problems.
Mike
Standard mode will maintain the set temp to whatever it's set for.
Economy mode will heat only when the spa is in a filter cycle. The spa will monitor the water temp several times a day and won't allow the spa to lose more than 20 degrees below set temp. If you're in a routine and use your spa at the same times everyday you can program the filter cycles to start about an hour before your soak so it's up to temp for you.
Sleep mode will allow the spa to lose and maintain a temp of 20 degrees below set temp all the time it's in that mode. This is handy for when you go on vacation and don't want to maintain higher temps while gone.
Lets say you want your water at 99 degrees and you're in economy..The spa temp may go below that between filter times but as soon as it starts to filter the heator will kick on to raise the temp to 99 degrees. But the thermal lock is also trapping the heat in, and so while the heater came on to raise the temp, you'lll experience heat creep because the thermal lock would have been enough to raise the temp.
In the sleep mode the spa may lose a few degrees between filter cycles but when the filter cycle comes on the heater won't and so you're just dealeing with the thermal lock heat.
Your AM and PM filter cycles don't have to be the same duration. If you have heavier use in the evening set the filter cycles to run 4 to5 hours then, and 3 to 4 hours in the morning.
During the heaviest use I think it's important program the spa to filter about the time you get out. It takes about 30 minutes for oil and water to separate. We have oil in our skin, makeup, hair gel, deoderant ect. So when this happens it make sense to have the spa start to filter.
I hope this makes sense I'm running on very little sleep because of nightly severe storms for the last 5 nights up here. If you have any questions feel free to PM me.
Spahappy :D
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Hm... I think perhaps some testing is needed here... :) I still think (I sure can be wrong, don't misread me...) that a 1/20 HP pump (what SD uses in 800 series... dunno what others use) would have a hard time heating up cold water that much. (Especially compared to the heat of the sun, and especially when we wait so long for cold water to heat up using a many KW heater when we refill!)
Are we really getting to a consensus that the 24/7 fractional HP circ pumps add that much heat? I'm willing to be convinced, but didn't think it was so...
You'd think if this was such a prevalent problem, there would be a better means to vent the heat/cool it down besides just 'summer/economy' modes, which only stop the pumps, and don't actually cool anything.
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Many times customers with a circ pump spas have turned their spas on after a refill or at startup and the water heats up to about 80º or so but no further. They assume since it did heat up some that the heater was energized. All along the issue was the heater was not energized and the heating they saw was simply from the circ pump but fooled them and all along they needed to reset their heater or maybe its a spa where the heater has a separate breaker and that has to be reset. Many circ pumps can be VERY efficient at transferring their heat depending on the type used.
Beat me too it! 8) If the water is 40 degrees then I would believe the circ pump can raise it 10 degrees in temperature.
However, The circ pump alone is not raising my water from 90 to 100 degrees! What do you think this is, an Arctic ad? ;)
Iwill run an experiment if I remember... I will leave the cover open for 30 minutes at noon (to bring the temp down a little) then put he cover on for 3 hours and then take the tub's temperature at 3pm.
Then, I'll take the cover off again at 8pm for 30 minutes (to bring the temp down) then put the cover on for 3 hours and take the tub's temp again at 11pm.
I'm going to bet that the tub at 11pm is cooler than the tub at 3pm. I'll further bet that it "drops" in coolness by more than the daily temperate shift between 3pm and 11pm, but I could certainly be wrong!
-Ed
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Many times customers with a circ pump spas have turned their spas on after a refill or at startup and the water heats up to about 80º or so but no further. They assume since it did heat up some that the heater was energized. All along the issue was the heater was not energized and the heating they saw was simply from the circ pump but fooled them and all along they needed to reset their heater or maybe its a spa where the heater has a separate breaker and that has to be reset. Many circ pumps can be VERY efficient at transferring their heat depending on the type used.
This was not my experience. Monday I received my tub, ambient temp was about 90. I filled the tub with water and took a reading: 65 degrees.
I did have the heater off. (didn't realize it though) ran the circ pump for about 24 hours and spa temp had only increased to 72 degrees and i would attributee the temp change to fact the tub was sitting in the sun, not heat thrown off by the circ pump.
I find it hard to believe a circ pump can raise 350 gals of water 10 degrees simply by the heat of the pump. I'd also think you have a problem if that was a full foam tub we are taking about.
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I did have the heater off. (didn't realize it though) ran the circ pump for about 24 hours and spa temp had only increased to 72 degrees and i would attributee the temp change to fact the tub was sitting in the sun, not heat thrown off by the circ pump.
I would have to differ. That 7º is mostly from your circ pump.
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Hm... I think perhaps some testing is needed here... :) I still think (I sure can be wrong, don't misread me...) that a 1/20 HP pump (what SD uses in 800 series... dunno what others use) would have a hard time heating up cold water that much.
It depends on what circ pump you have but pleas, check it out for yourself. I say this only because I've seen it many times. BTW, when I mentioned it heating a spa to about 80º I should have mentioned I was talking about the water starting at about 68 or so on a average temp day. Give it 24 hrs and it can definitely raise the temp 10º. Now if its the dead of winter or super hot its effect increases or decreases but you will find the circ pump add noticeable heat to the water. Test it yourself and report back.
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I would have to differ. That 7º is mostly from your circ pump.
A small circ pump in a cabinet, seperated from the water by 12" of dense foam is going to heat my ff tub of 320 gals, more so than sitting in the direct 90' sunlight, bearing down on a spa cover with a surface area of 49 square feet? nah. no way.
Of course I am far from qualified to argue this point, I just find that hard to belive.
:)
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1. Unfortunately, I am spa-less (as my title implies... :) ), so I can't test.
2. My engineering sense agrees with drewster. But we need some empirical tests on a cool cloudy day... ;D ;D
The thermodynamics of this don't seem to add up, but I could be all wet...
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A small circ pump in a cabinet, seperated from the water by 12" of dense foam is going to heat my ff tub of 320 gals, more so than sitting in the direct 90' sunlight, bearing down on a spa cover with a surface area of 49 square feet? nah. no way.
Of course I am far from qualified to argue this point, I just find that hard to belive.
:)
I'm only going from experience as I've seen it too many times.
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A small circ pump in a cabinet, seperated from the water by 12" of dense foam is going to heat my ff tubof 320 gals, more so than sitting in the direct 90' sunlight, bearing down on a spa cover with a surface area of 49 square feet? nah. no way. Of course I am far from qualified to argue, I just find that hard to belive.
The heat transfer TUO was referring to is not ambient heat from the motor, but rather heat generated in magnetic drive circ pumps. This heat is transferred to the water in the wet end of the pump.....
How did I do T.U.O.?
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The heat transfer TUO was referring to is not ambient heat from the motor, but rather heat generated in magnetic drive circ pumps. This heat is transferred to the water in the wet end of the pump.....
How did I do T.U.O.?
Excellent. I realize people have a hard time believing there is much transfer but once they test it for themselves they'll be scratching their heads and then maybe I can get some respect around here. ;D
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Oh, I agree. The issue is like hot water heating in a house: the water goes through the boiler, and is heated. In this case, the warm/hot pump has the water circulating through it, and the heat of the motor is conducted to the water. It's not the heat of the pump migrating to the great body of the spa water itself.
But, I still have a problem with the magnitudes of the heat of the pump, the amount of the water, the amount of time the water is in the pump, etc.
A *real* test needs a pump, and two of these thermometers we use for grilling, that go to 0.1 degree. They could tell us how much the water is heated as it passes through the circ pump. That with the flow rate would tell us what's up. We can even make the (faulty) assumption that the insulation is perfect, just for grins.
(Anyone want to ship me a circ pump? I can mock up the rest? :) )
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Excellent. I realize people have a hard time believing there is much transfer but once they test it for themselves they'll be scratching their heads and then maybe I can get some respect around here. ;D
Maybe you should change your handle to "Mr Dangerfield" ;)
Please don't confuse my ignorance with lack of respect.
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And, me neither. I just like to find factual reasons for things, not WAGs... :D
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If the heat in the spa cannot make it through the top of the spa and melt the ice on top, or make it through the cabinet, then think of it the other way around.
The main reason that the laing circ pump can generate this much heat is because it uses the water passing through it to cool it off. The ambient temperature only means that the circulation pump will be almost solely relying on the water to cool itself off. Even with the vents, if the ambient air is above 90, the air will have a hard time helping to cool the pump.
To prove that the ambient air is not heating the water, shut the circulation pump off. The tub will probably maintain its heat, dropping in temp only slightly on a warm day.
Turn the circulation pump on the next day, and watch the temperature rise.
The flow rate through the laing circulation pump is roughly 9gpm.
Along with ST T.U.O I have personally seen this many times.
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And, me neither. I just like to find factual reasons for things, not WAGs... :D
I was merely joking on the respect comment. I too am one that belives best when I can touch, feel, study and see for myself so please do test this for yourself. Next time you fill the spa do so late afternoon when the sun is down if that makes you feel better and turn on the circ pump with the heater de-energized. Let the spa run with just the circ pump overnight and see what happens to the temp. Then send me a coupon for a free Starbucks cause "I told you so".
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That's a good test (too bad I can't do it.. ). Overnight, with cool water, any rise in temp will be totally from the circ pump heat/friction, as long as everything else is off (other pumps, heater, duh... :) ).
Any takers?
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That's a good test (too bad I can't do it.. ). Overnight, with cool water, any rise in temp will be totally from the circ pump heat/friction, as long as everything else is off (other pumps, heater, duh... :) ).
Any takers?
You could simply disconnect the heater for your next refill if you really want to check it out.
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All of this info is a lot to absorb right now and I'm in a hurry to leave for the holiday but I wanted to clear some things up and check back later....
I wasn't planning on it, but we re-filled the tub yesterday because of excessive body oils in the water. When I reached the fill mark (in 40 mins. by the way) at 8:30 PM, I turned the power back on and my water temp was 57 degrees. I set the temp for 95, added some "metal gone", set both of my circ times for 11:00 to 5:00, closed the lid and walked away. When I opened the lid this evening to test the water, my temp was at 100 degrees.
So... in one day, my water went above the set temp. I don't know if it was heat created by water going thru the pumps or radiant heat from the pump retained within the insulation. My dealer says it's radiant...
Spahappy,
After a short soak and an application of Dichlor, I set the mode to sleep (SLP) tonite and closed the lid. I'm not going to be back until tuesday so I'll let you know what I see when I return.
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I thought we were ready to go but she's not finished packing yet. I'll bet you guys can't believe that can you :)
While I had a few moments, I wanted to add this... Our hot tub is located on our basement porch under a roof. This is about the coolest place on our property right now - not out in the direct sunlight.
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Oh, I agree. The issue is like hot water heating in a house: the water goes through the boiler, and is heated. In this case, the warm/hot pump has the water circulating through it, and the heat of the motor is conducted to the water. It's not the heat of the pump migrating to the great body of the spa water itself.
But, I still have a problem with the magnitudes of the heat of the pump, the amount of the water, the amount of time the water is in the pump, etc.
A *real* test needs a pump, and two of these thermometers we use for grilling, that go to 0.1 degree. They could tell us how much the water is heated as it passes through the circ pump. That with the flow rate would tell us what's up. We can even make the (faulty) assumption that the insulation is perfect, just for grins.
(Anyone want to ship me a circ pump? I can mock up the rest? :) )
i dont know..... you "mocking up" the rest may not give a true representation of the spas in question. if you could only find a company that would ship you the whole spa ::) ;), for research purposes only, of course ;D ;D. for the best results, you will really need to sample the effects in various seasons, to get an average.... so you would have to monitor the results for a least a year, maybe several years...... all in the name of science ;D
you know, i already have a caldera, but if another manufacturer wants to ship ME one of thier spas, i would be more than happy to do a comparison testing of the 2 spas. in the name of research and all......
all the important facts.. heat transfer, model, oerational costs, how many people come to my house with 2 SPAS. etc...
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Yeah, you're right... might take some time with an assortment of gauges and various types of waters and 'brands' of power and variations of sunlight to be sure on the source of the heating.... Think Sundance will go for a Max for a demo for 5 years?! ;D ;D ;D ;D
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I wasn't planning on it, but we re-filled the tub yesterday because of excessive body oils in the water. When I reached the fill mark (in 40 mins. by the way) at 8:30 PM, I turned the power back on and my water temp was 57 degrees. I set the temp for 95, added some "metal gone", set both of my circ times for 11:00 to 5:00, closed the lid and walked away. When I opened the lid this evening to test the water, my temp was at 100 degrees.
Well, either I'm confused or you are saying you set the heater for 95 degrees. Do you mean that the extra 5 degrees came from the pumps' heat or what? Or did you leave out that you turned the heater off or something?
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Well, either I'm confused or you are saying you set the heater for 95 degrees. Do you mean that the extra 5 degrees came from the pumps' heat or what? Or did you leave out that you turned the heater off or something?
Yes, I'm saying that my heater was set to 95 degrees so it was "turned on" at 8:30. In the winter, it heats my water at 6 degrees per hour so the thermostat probably turned the heater off at about 2:45 or earlier. My circ pump was set to run from 11:00 until 5:00 so the pump ran another 2 hours and 15 minutes beyond the heater shutdown. The circ pump kicked on again at 11:00 in the morning and I checked the temp 4 hours later. At that time, it was 5 degrees hotter than I had the thermostat set to the day before.
Spahappy,
That same evening, I set the mode to Sleep and closed the lid before I left for vacation. When I got back this morning, my temp was at 101 degrees. Maybe this other mode isn't going to help me ???
I believe you and my dealer are both correct in saying that the circulator pump will give off enough heat to cause this problem in the summer. Since the Coleman hot tubs don't have full foam insulation, the underside of the tub can absorb the rising heat. It may be a slight problem in the summer but I believe this extra heat source will save me a lot of money during the northeast winters :)
I think we're going to stuff a towel under the lid and see what we get from that.
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My experience with our Optima is, if the surrounding ambient temperature is above a certain point (mid 80s), the spa will gain heat with the main pumps, and will not lose any, with the heater turned off totally and the cover on.
And if the stat is set for 98 degrees, with the above conditions, if the spa main pumps are ran too long (over an hour), the temp will get up to 101 degrees, which locks out the circulator and ozonator. Which means no sanitizing.
What we do is uncover the spa, 2-3 hours before use, so that the temp goes down to 96.
It's not so much that the pumps are adding that much heat, it is that the temp of the air compared to the water is too close for any quick heat transfer.
My suggestion to Sundance would be to make the thermostat differential adjustable, with a wider “deadband”. Or do it automatically, depending on surrounding temperature.