Do you run your heater to make CL with your SWG in the winter?

mguzzy

Well-known member
Jul 8, 2015
862
OV, CA
Is that a stupid question? yeah.. if its from my brain, probably. :rolleyes:

So, alas, that time of year has come to my pool; its cold enough that the SWG is not producing. Unless heated, my pool will hover around the mid 50's for the rest of the winter. Wait a minute.. he says, "unless heated" rolls around the thought process for a second and regurgitates a half baked idea.... So the question to the forum is: has anyone tried running their heater to raise the temp enough to generate CL? My SWG is in line after the heater and I get about 8.5 degrees rise in temp from the heater, soooo theoretically I can run the heater and make CL. And I tried it and yes it works.. but I didn't quantify it with before and after testing. I'm just too dern lazy. Is it worth it? probably not. I'm sure 10 bux in LC will be cheaper than the equivalent amount of NG I burned off. But I was curious if anyone else has tried this.

Perhaps this thought experiment should be in the Deepend.. but I stuck it here
 

Donldson

TFP Expert
LifeTime Supporter
In The Industry
Jun 12, 2009
3,958
NW Ohio
Your heater will have a minimum operating water temperature of around 60 F. This is because running water cooler than that will cause the exhaust fumes to condense in to an extremely acidic liquid on the heat exchanger, which will eat right through it. I'm betting your heat exchanger is worth more than $10.
 

Newdude

Well-known member
Jun 16, 2019
1,623
NY
As you found out it will work. But the cost...... ouch. Pocket 90% of the NG cost and use the other 10% to hire amd errand service to go get you chlorine. There's seveal apps like door-dash but for menial errands.
 

mguzzy

Well-known member
Jul 8, 2015
862
OV, CA
You guys crack me up.. I would never order Dominos! I still have PTSD from my college Dominos experiences....

I never thought of the effect on the heat exchanger.. even when heating the spa/pool up in the winter time, but that's probably because it doesn't stay at that temp for long.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
11,691
Northern NJ
I never thought of the effect on the heat exchanger.. even when heating the spa/pool up in the winter time, but that's probably because it doesn't stay at that temp for long.
As long as you heat the water from cold to over 70F in one cycle, condensation will not damage the heater.

If you set the heater temperature to cycle below 60F then condensation becomes a problem.
 

mguzzy

Well-known member
Jul 8, 2015
862
OV, CA
@ajw22 Yep... just as I thought.. Per your link, you can heat a pool/spa from temp below the minimum as long as you continue to heat it to above the minimum temp. Thx

we posted at the same time.. yup
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
12,872
Pleasanton, CA
When the water is too cold to generate chlorine, it is usually too cold to have an algae problem. I don't do anything when my swg shuts off due to cold water. I just ride out the cold spell.

However, if water temps climb too quickly for the swg to make up, you may need to help it out with a little LC.
 
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mguzzy

Well-known member
Jul 8, 2015
862
OV, CA
@mas985 Yeah.. I would agree with that statement and it is true by the time winter sets in. But my pool is unique in that it sits within a Stonehenge like circle of trees; large oaks on one side and mature redwoods on another where the only sunlight squeezes through the gaps. The temps on my pool are cooler than everyone else in the neighborhood as a result. So when the temps drop as the seasons change, my pool will get to the "your SWG won't work" temp before the algae has turned on its winter snooze alarm. Its during that roughly one month during the fall I was toying with other ideas of extending my SWG production... hence this thread.
 

JamesW

TFP Expert
Mar 2, 2011
16,977
You could cut into the cord and bypass the thermistor with a 10k resistor. That would make the temperature read as 77 degrees and it would generate chlorine.

However, it's definitely not worth doing.

The efficiency is reduced and you don't need much chlorine anyway.

You would also void the warranty and you could damage the system if anything went wrong.
 

mguzzy

Well-known member
Jul 8, 2015
862
OV, CA
@JamesW , Well that sounds like a fine hack ;).... I've also read (I don't recall the source) that I can just set the controller to superchlorinate and it will produce chlorine regardless of the temp. The CL production is suppressed simply because of reduced temps in that situation. Not sure if that works with other SWGs or just the Haywards.

All in all looks like going back to the jug is the best option...
(Ha ha ha, you and me... little white jug how drunk we'll be...)
 

JamesW

TFP Expert
Mar 2, 2011
16,977
At 50 degrees Fahrenheit, the display will say "Cold" and it will stop working even if set to Superchlorinate.

At 60 degrees Fahrenheit, the output is reduced to 20% of the setting. So, 100% would be 20%, 50% would be 10% etc.
 

mguzzy

Well-known member
Jul 8, 2015
862
OV, CA
Got it! thanks for the clarification @JamesW . My pool has never gotten below 50 deg.. But in the winter I usually just turn the controller off. I have never had "freezes" where I have had to worry about the pool equip.
 

C0d3Sp4c3

Member
Dec 10, 2018
19
NorCal
At 50 degrees Fahrenheit, the display will say "Cold" and it will stop working even if set to Superchlorinate.

At 60 degrees Fahrenheit, the output is reduced to 20% of the setting. So, 100% would be 20%, 50% would be 10% etc.
Any logical reason other than chlorine demand is lower during cold months? Would there be an impact on the cell to force produce CL at <50°F
 

mguzzy

Well-known member
Jul 8, 2015
862
OV, CA
Well... during the winter there is less bio activity so less algae.. so I turn my pump runtime down. To make enough CL with the lower SWG production I would have to turn my runtime up actually... that's why I just turn it off and switch to LC for the wintry months. My notion of running the heater was a thought experiment.. but I now think not ;)