Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 20 of 20

Thread: Just adding RV antifreeze vs Blowing main drain for winter.

  1. Back To Top    #1

    Join Date
    May 2015
    Location
    NW Indiana
    Posts
    21

    Just adding RV antifreeze vs Blowing main drain for winter.

    I found an old post about closing the pool for winter in this forum and it was discussed the easier method of just adding enough RV antifreeze to the main drain without blowing it out first and when the antifreeze starts oozing out of the main drain you just close and cap the valve for the MD. I will like to know if anybody have used this method and could tell how good it works? What will be any downsides? All I can see is advantages since its seems pretty easy to do without buying or using any shop vacs or compressors. 1 gal of rv antifreeze goes for about $3 or less.
    19K gal AG. 200 Swimpro Element Filter. 2HP, Dual Speed Voyager. TF-100.

  2. Back To Top    #2
    dw9000's Avatar
    Join Date
    Aug 2014
    Location
    NW Ohio
    Posts
    178

    Re: Just adding RV antifreeze vs Blowing main drain for winter.

    I don't see how that would work, if you don't blow out the line the water will stay and the antifreeze will never reach the drain. You could blow it out, and instead of slamming the valve shut creating the air lock, you could try and quickly pour in a few gallons,, then blow a little more that would push it and once you see the pink come out the drain you could slam the valve shut.
    In-ground block / vinyl liner 33' x 22' x 5',, approx 25k gals
    Cartridge Filter
    Floor drains, 2 skimmers, 3 return lines (2" plumbing ultra-flex PVC)

  3. Back To Top    #3

    Join Date
    May 2015
    Location
    NW Indiana
    Posts
    21

    Re: Just adding RV antifreeze vs Blowing main drain for winter.

    I think antifreeze has no problem filling the main drain because is heavier than water.i will try to close my pool using this method I will post about it later.
    19K gal AG. 200 Swimpro Element Filter. 2HP, Dual Speed Voyager. TF-100.

  4. Back To Top    #4

    TFP Guide

    Catanzaro's Avatar
    Join Date
    Jul 2014
    Location
    Monmouth County, New Jersey
    Posts
    2,175

    Re: Just adding RV antifreeze vs Blowing main drain for winter.

    I don't see how that would work, if you don't blow out the line the water will stay and the antifreeze will never reach the drain. You could blow it out, and instead of slamming the valve shut creating the air lock, you could try and quickly pour in a few gallons,, then blow a little more that would push it and once you see the pink come out the drain you could slam the valve shut
    I agree with dw900. If we are talking about the skimmers, I would see no problems as the skimmers can be isolated and closed off from both ends (equipment pad and with the Gizmo's). Water at the main drain (and in the piping), can mix and travel, thereby entering the pool water. There is a term, but I just can not remember. For example, I have hot water baseboard heating in my home. If I open all the valves upstairs without the heat and only run the downstairs, slowly the water will continue to mix with the hot water on the first floor and bring it to the second floor. I believe the concept will be the same with the pool. If the valves are closed, no water will mix. In my opinion, so will pouring RV Antifreeze eventually enter the pool.

    An "Air Lock" traps air from the equipment pad (Jandy Valve) to the main drain so gravity does not allow water to travel up to the frost line. In order to ensure added protection, I always recommend a black rubber plug in the pump housing. The black plug should be sticking out about 1/8" and be placed on tight.
    14,700 gallons IG Pool Vinyl Liner - Octal Circulation System
    Hayward Pro-Series 350 LB. Sand Filter Model # S270T - 2" Plumping
    Hayward CL2002 Chlorinator - Hayward Super Pump 2 HP Model # k48m2n111
    Hayward AQR9 SWG 25K Salt Cell & TF-100 Test Kit + Speed Stir
    Gulfstream HE125RA - 117K BTU Heat Pump - Date of Build is 11-2013

  5. Back To Top    #5

    Join Date
    Apr 2010
    Location
    Central NJ
    Posts
    223

    Re: Just adding RV antifreeze vs Blowing main drain for winter.

    Quote Originally Posted by Catanzaro View Post
    I always recommend a black rubber plug in the pump housing. The black plug should be sticking out about 1/8" and be placed on tight.
    hmmm...good idea. Do you use a butterfly?
    23K gallon, IG, Vinyl, Hayward DE-3600 Filter, Raypak 406A Heater, Hayward 1.5HP SP2610X15 pump aka AO Smith UST1152, TF-100 Test Kit

  6. Back To Top    #6

    TFP Guide

    Catanzaro's Avatar
    Join Date
    Jul 2014
    Location
    Monmouth County, New Jersey
    Posts
    2,175

    Re: Just adding RV antifreeze vs Blowing main drain for winter.

    hmmm...good idea. Do you use a butterfly?
    Assuming you mean a Wing Nut! Yes.

    IMG_1006.jpg
    14,700 gallons IG Pool Vinyl Liner - Octal Circulation System
    Hayward Pro-Series 350 LB. Sand Filter Model # S270T - 2" Plumping
    Hayward CL2002 Chlorinator - Hayward Super Pump 2 HP Model # k48m2n111
    Hayward AQR9 SWG 25K Salt Cell & TF-100 Test Kit + Speed Stir
    Gulfstream HE125RA - 117K BTU Heat Pump - Date of Build is 11-2013

  7. Back To Top    #7

    Join Date
    Jun 2015
    Location
    East Hampton CT
    Posts
    375

    Re: Just adding RV antifreeze vs Blowing main drain for winter.

    My Dad has had an IG pool for near 30 years and I have owned mine for 8 seasons. Never once in over 35 closings have we been able to blow out the main drain. Even when the water is below the returns, I estimate about 14,000 gallons of water, and though we try, 14k gallons of water is an immovable object compared to the resistible force of a 6 HP shop vac (which blows out the rest of the plumbing just fine). Our strategy is to put between a 1/2 -3/4 gallons of anti-freeze into the main drain and call it a day. All the other plumbing is blown out and capped at the pool end. Never had a problem.
    Chris
    17' x 35' outdoor in-ground Grecian shaped w/ vinyl liner. ≈ 21,000 gallons. Hayward S-200 Sand Filter and 1 HP Hayward Super-pump. Other Accessories: slide, light, ladder, fiberglass stairs, TF-100. Baquacil Conversion - June 2015, SLAM How-to, Chlorine/CYA Chart

  8. Back To Top    #8

    TFP Guide

    pabeader's Avatar
    Join Date
    May 2015
    Location
    Dallas Ga
    Posts
    4,064

    Re: Just adding RV antifreeze vs Blowing main drain for winter.

    Well if you think about it, even in CT, the water isn't going to freeze way down at the depth of the main drain. It's just the 3 or 4 feet on the way down that may have an issue. I would think.
    Bob - Palm Beach by San Juan Pools. approx 5000 gals., Pentair 320 cartridge filter (all new guts installed by me), Goldline SWG, 'New to me' Kreepy Krauly Sand Shark, Intermec 104 Timer Test kit: TF-100 w/Speed Stir

  9. Back To Top    #9

    TFP Guide

    Catanzaro's Avatar
    Join Date
    Jul 2014
    Location
    Monmouth County, New Jersey
    Posts
    2,175

    Re: Just adding RV antifreeze vs Blowing main drain for winter.

    Quote Originally Posted by Husky25 View Post
    My Dad has had an IG pool for near 30 years and I have owned mine for 8 seasons. Never once in over 35 closings have we been able to blow out the main drain. Even when the water is below the returns, I estimate about 14,000 gallons of water, and though we try, 14k gallons of water is an immovable object compared to the resistible force of a 6 HP shop vac (which blows out the rest of the plumbing just fine). Our strategy is to put between a 1/2 -3/4 gallons of anti-freeze into the main drain and call it a day. All the other plumbing is blown out and capped at the pool end. Never had a problem.
    This kind of makes sense. One would wonder when no Anti-Freeze is poured in the lines, if a problem could exist when it is real cold. I am guessing the Anti-Freeze in the MD will not stay there for long.

    A couple of other items that I have noticed, which I will pay a little more attention to this winter. The ice that forms on the pool surface (under the cover) for some reason is not completely frozen near the liner, therefore indicating that the liner, steel wall and soil behind it somehow insulate that small area (probably 1"). The water is only frozen at most 1"-2" at the surface, meaning the remaining water in the pool is over freezing temperatures.

    Additionally, the returns jets (not on the walls, but the bottom of the piping) are encased in about 6" of concrete (called the collar) which runs all the way around the pool and a few feet off the diving board. This also insulates the pipes in the ground (3' down) + a few inches. The filter is located about 2-3' higher, making gravity naturally take water downhill. Lastly, the 5' of concrete around the pool (naturally graded for water run-off), at least for me, will not allow water to sit, freeze and expand over time. Assuming soil outside concrete will put some pressure from expansion, but not enough to make a difference.

    One should always assume worst case scenario, as breaking up 60,000 lbs. of concrete to fix plumbing lines may not be very cost effective.
    14,700 gallons IG Pool Vinyl Liner - Octal Circulation System
    Hayward Pro-Series 350 LB. Sand Filter Model # S270T - 2" Plumping
    Hayward CL2002 Chlorinator - Hayward Super Pump 2 HP Model # k48m2n111
    Hayward AQR9 SWG 25K Salt Cell & TF-100 Test Kit + Speed Stir
    Gulfstream HE125RA - 117K BTU Heat Pump - Date of Build is 11-2013

  10. Back To Top    #10

    Join Date
    Jun 2015
    Location
    East Hampton CT
    Posts
    375

    Re: Just adding RV antifreeze vs Blowing main drain for winter.

    Quote Originally Posted by Catanzaro View Post
    This kind of makes sense. One would wonder when no Anti-Freeze is poured in the lines, if a problem could exist when it is real cold. I am guessing the Anti-Freeze in the MD will not stay there for long.
    In theory, antifreeze is sort of a redundancy. If all the lines are blown out and capped, there is nothing for the antifreeze to keep from freezing. However if there is a leaky cap, the antifreeze will, at worst, create a slush. When it comes to the main drain, if you detach the tank from the plumbing, that whole end is open. So if water does freeze, there is non-airtight room for expansion. On the other hand I think the piece of mind is well worth the $9.38 for 3 bottles of antifreeze.
    Chris
    17' x 35' outdoor in-ground Grecian shaped w/ vinyl liner. ≈ 21,000 gallons. Hayward S-200 Sand Filter and 1 HP Hayward Super-pump. Other Accessories: slide, light, ladder, fiberglass stairs, TF-100. Baquacil Conversion - June 2015, SLAM How-to, Chlorine/CYA Chart

  11. Back To Top    #11

    TFP Guide

    Catanzaro's Avatar
    Join Date
    Jul 2014
    Location
    Monmouth County, New Jersey
    Posts
    2,175

    Re: Just adding RV antifreeze vs Blowing main drain for winter.

    So if water does freeze, there is non-airtight room for expansion
    I actually have a 3" schedule 40 PVC with 2 end caps that I will be using as an experiment this winter (outside). The bottom cap is going to be glued together and filled up with water all the way to the top and then capped off. The whole 4' PVC will be standing upright against the corner wall (near my office) so I can watch it closely to determine if the water will expand up into the cap and/or towards the sides and break the PVC. This will be an interesting one.

    I tested out a Corona bottle (filled up about 80% of the way up) and the bottle broke in the freezer. (Had it is a thick plastic bag so there would be no damage). The force was out, not up. This was glass. I know thin plastic expands drastically. So this will be interesting regarding the white PVC.
    14,700 gallons IG Pool Vinyl Liner - Octal Circulation System
    Hayward Pro-Series 350 LB. Sand Filter Model # S270T - 2" Plumping
    Hayward CL2002 Chlorinator - Hayward Super Pump 2 HP Model # k48m2n111
    Hayward AQR9 SWG 25K Salt Cell & TF-100 Test Kit + Speed Stir
    Gulfstream HE125RA - 117K BTU Heat Pump - Date of Build is 11-2013

  12. Back To Top    #12

    TFP Guide

    pabeader's Avatar
    Join Date
    May 2015
    Location
    Dallas Ga
    Posts
    4,064

    Re: Just adding RV antifreeze vs Blowing main drain for winter.

    It will bust through the side. It has to do with how the ice forms within the tube.
    Bob - Palm Beach by San Juan Pools. approx 5000 gals., Pentair 320 cartridge filter (all new guts installed by me), Goldline SWG, 'New to me' Kreepy Krauly Sand Shark, Intermec 104 Timer Test kit: TF-100 w/Speed Stir

  13. Back To Top    #13

    TFP Guide

    Catanzaro's Avatar
    Join Date
    Jul 2014
    Location
    Monmouth County, New Jersey
    Posts
    2,175

    Re: Just adding RV antifreeze vs Blowing main drain for winter.

    Quote Originally Posted by pabeader View Post
    It will bust through the side. It has to do with how the ice forms within the tube.
    In your opinion, (talking about the pool plumbing only), if there was 50% of the water left in all the plumbing, could it cause any issues?

    Most plumbing lines are not completely free of all water, even upon closing as they are plugged off. Only if the water was drained below the returns, could you possibly remove 100% of the water, which is not what everyone does. Some PB close pools with water filled 1/2 way in the skimmer. Just curious to know what your thoughts were. Of course, we all know the MD can not be plugged.
    14,700 gallons IG Pool Vinyl Liner - Octal Circulation System
    Hayward Pro-Series 350 LB. Sand Filter Model # S270T - 2" Plumping
    Hayward CL2002 Chlorinator - Hayward Super Pump 2 HP Model # k48m2n111
    Hayward AQR9 SWG 25K Salt Cell & TF-100 Test Kit + Speed Stir
    Gulfstream HE125RA - 117K BTU Heat Pump - Date of Build is 11-2013

  14. Back To Top    #14

    Join Date
    May 2013
    Location
    Long Island NY
    Posts
    419

    Re: Just adding RV antifreeze vs Blowing main drain for winter.

    I have always only put Antifreeze in the skimmer boxes and skimmer lines. As far as the MD goes,the remaining water in the pipe is below frost line so no antifreeze needed.
    19,000 gal - Vinyl IG - Sand filter -1.5hp. - Taylor k 2006 - Loop Loc cover

  15. Back To Top    #15

    TFP Guide

    pabeader's Avatar
    Join Date
    May 2015
    Location
    Dallas Ga
    Posts
    4,064

    Re: Just adding RV antifreeze vs Blowing main drain for winter.

    That's what I was getting at earlier. If it's in the ground below the frost line it's safe.
    Bob - Palm Beach by San Juan Pools. approx 5000 gals., Pentair 320 cartridge filter (all new guts installed by me), Goldline SWG, 'New to me' Kreepy Krauly Sand Shark, Intermec 104 Timer Test kit: TF-100 w/Speed Stir

  16. Back To Top    #16

    Join Date
    May 2015
    Location
    NW Indiana
    Posts
    21

    Re: Just adding RV antifreeze vs Blowing main drain for winter.

    I just finished blowing the main drain of my agp a small 2 hp (armour all) did the job. I let it run for about 1 minute. Plenty of bubbles were coming out and then closed the valve and capped the 2 openings on the valve.I didn't use the antifreeze after all since the small shop vac was enough to blow the main drain (1 1/2" and about 15' long ) some pics here Google Photos
    19K gal AG. 200 Swimpro Element Filter. 2HP, Dual Speed Voyager. TF-100.

  17. Back To Top    #17

    Join Date
    May 2015
    Location
    NW Indiana
    Posts
    21

    Re: Just adding RV antifreeze vs Blowing main drain for winter.

    Quote Originally Posted by pabeader View Post
    That's what I was getting at earlier. If it's in the ground below the frost line it's safe.
    Frostline in northern IN is about 4' the MD of my above ground pool is about 2'deep. I wonder if the water above it acts as insulation.
    I just blowed out the MD and didn't add any antifreeze, hope the air stays there until next spring.
    19K gal AG. 200 Swimpro Element Filter. 2HP, Dual Speed Voyager. TF-100.

  18. Back To Top    #18

    TFP Guide

    Catanzaro's Avatar
    Join Date
    Jul 2014
    Location
    Monmouth County, New Jersey
    Posts
    2,175

    Re: Just adding RV antifreeze vs Blowing main drain for winter.

    Frostline in northern IN is about 4' the MD of my above ground pool is about 2'deep. I wonder if the water above it acts as insulation.
    I just blowed out the MD and didn't add any antifreeze, hope the air stays there until next spring.
    I would assume that water does act as an insulation. This winter, I will pay closer attention to the thickness of ice that freezes on the surface. The ground surface, line, steel walls should also act as insulation, or one would see at least a foot of frozen water on the pool surface.

    I believe the layer of ice on the top actually protects the water on the bottom from freezing, especially as wind is a big contributing factor to water freezing.
    14,700 gallons IG Pool Vinyl Liner - Octal Circulation System
    Hayward Pro-Series 350 LB. Sand Filter Model # S270T - 2" Plumping
    Hayward CL2002 Chlorinator - Hayward Super Pump 2 HP Model # k48m2n111
    Hayward AQR9 SWG 25K Salt Cell & TF-100 Test Kit + Speed Stir
    Gulfstream HE125RA - 117K BTU Heat Pump - Date of Build is 11-2013

  19. Back To Top    #19

    Join Date
    May 2013
    Location
    Long Island NY
    Posts
    419

    Re: Just adding RV antifreeze vs Blowing main drain for winter.

    Quote Originally Posted by puchasr View Post
    Frostline in northern IN is about 4' the MD of my above ground pool is about 2'deep. I wonder if the water above it acts as insulation.
    I just blowed out the MD and didn't add any antifreeze, hope the air stays there until next spring.
    Since you did blow out the MD you also created air space in the pipe, if it does freeze at least it has room for expansion.

    Now if it was a solid pipe full of water, maybe a different story at that depth.
    19,000 gal - Vinyl IG - Sand filter -1.5hp. - Taylor k 2006 - Loop Loc cover

  20. Back To Top    #20

    Join Date
    Mar 2007
    Location
    San Rafael, CA USA
    Posts
    12,082

    Re: Just adding RV antifreeze vs Blowing main drain for winter.

    The thermal conductivity of water is around 0.6 W/(m K) while for ice it's 2.22 W/(m K) at freezing and goes higher as the temperature drops. The thermal conductivity of concrete varies but is roughly on the order of 1 W/(m K). The thermal conductivity of soil varies a lot depending on soil type and water content but roughly will be in the concrete to ice range.

    So while the initial layer of ice prevents evaporative cooling, after that there is probably more loss of heat per square foot through the ice than through the pool walls, at least until the ice was roughly twice as thick as those walls. Of course, the ground temperature makes a big difference here. I wonder if the ice depth level in a pool is the same level as the frost line. It's probably close though perhaps may go somewhat below that due to the greater thermal conductivity of pure ice compared to frozen soil. Anyone have any experience with that (i.e. measured ice depth in pool vs. ice depth in soil)?
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •