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Thread: Can't get main drain air lock to hold with Praher 3 port valve?!?!

  1. Back To Top    #1

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    Can't get main drain air lock to hold with Praher 3 port valve?!?!

    I am new to the forum, although I have been checking out threads for most of the summer since this was my first full season with a pool. I did a lot of research on winterizing my inground pool (18,500 g. fiberglass) and for the price of paying a company to winterize it for me, I purchased a Cyclone box blower to blow the lines out. I noticed that throughout the season, the suction on my vacuum seemed to be less than early on, despite making sure that the cartridge filter was clean, skimmers clear, etc. I also noticed that as I was draining the pool down below the skimmer basket using the main drain port on my 3 way Praher valve, the skimmer port was still drawing in some water as well. Once drained below the skimmer, I attached to blower to my skimmer inlet, opened the 3 port valve, so that the main drain port, skimmer port, and pump port were open and turned on the blower. After a minute or so, air started coming out of one jet return, which I let blow for a couple of minutes, then plugged it. Then air started coming out of my second return, which I repeated this process and plugged it. As expected, with the returns plugged and air locked, the main drain started blowing air, which I let go for a couple of minutes to purge as much water out of the plumbing as possible. I then turned the 3 way valve to the closed position, sealing off the main drain port to create an air lock and closing off the skimmer and pump ports as well (handle away from the pump port so that all 3 ports were closed). My wife immediately turned off the blower for me at the skimmer, as my equipment is 80 feet away from the pool. At this point, in theory my main drain should have been air locked. I was going to proceed to pour the pool antifreeze into the skimmer and plug it off, remove the drain plugs from my pool heater, filter housing, pump (2), and disconnect my UV sytem to store inside when I noticed water slowly returning into the pump chamber. Please note, my pool sits at a higher elevation than my pool equipment, so my valve does not appear to be sealing.

    My pool (and this 3 way valve) is only 1 year old, as it was put in a the tail end of last summer. The company that put in the pool did the first winterization, as it was part of the package deal. They want $350 to winterize it from this point further and did a very sloppy job (yet effective) last season, hence my desire to do this myself. For many years I have blown out and winterized both my hot tub and 15 zone sprinkler system, so I was pretty comfortable tackling this. The owner of the company that installed the pool did not make the process enjoyable at all, so I would prefer to not have to deal with him in the future. Does anyone have any thoughts as to what is going on with my 3 port Praher valve? My pool is very simplistic, it has one skimmer and the main drain on the intake side and 2 return jets on the return side.....no deck jets, waterfalls, spas, etc. There are 8 screws on the top of the valve, but I'm afraid to take this apart to check out the guts since my pool sits higher than the equipment. From what I'm reading this valve is supposed to be maintenance free, but being new to this stuff, I want to make sure that I'm not missing anything too obvious here. I have to hunt down my paperwork from all of the components associated with my pool to see if the valve is under warranty, which means that I may have to deal with this owner again, which I am dreading. Any thoughts as to what may be going on with this valve that clearly isn't sealing properly?

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    Praher Valve is not holding an airlock on main drain after blowing it out?!?!

    This is my first post to the forum, although I have been checking out the threads most of the summer, as this is our first full season with our pool.....good stuff on here!

    My pool was put in late last season and is an 18,500 fiberglass pool with a very simple set up. It has one skimmer and the main drain on the intake side and 2 return jets on the return side.....no deck jets, waterfalls, slides, spas, etc. The company installed a 3 port Praher valve with one port for the skimmer, one for the main drain, and the other out to the pump in the traditional fashion. I have noticed a few things this season with this valve. First, my vacuum suction has seemed to decline as the season has progress, despite making sure that the cartridge filter is clean and the skimmer baskets at the pool and in the pump are clear. Second, when draining the pool down below the skimmer using the main drain (handle of the Praher valve pointing towards main drain port, thereby opening the main drain and pump ports and closing the skimmer port), I noticed that the skimmer was still drawing in some water from the basket as well. Finally, I am unable to hold an air lock after blowing out the main drain, as water slowly returns to the pump housing with the valve completely closing off all 3 ports (handle pointing away from the pump port).

    The company that installed my pool late last season also winterized it the first year as part of their package deal. They did the winterization when I was not home and did a sloppy job with the winter cover, took my eyeball diverters, and broke the fitting to my Kreepy Kauly automatic vacuum system in the skimmer basket trying to remove it. I also have a UV system, which they disconnected from the plumbing and left sitting on the side of my house not telling me that it needed to be stored inside. The owner of the company that installed our pool made it a miserable experience for us, so I decided that rather paying them $350 to winterize my pool, I would invest that money into a Cyclone blower to winterize the pool myself. I blow out and winterize my own hot tub and 15 zone sprinkler system, so I figured that I could tackle this without too many hassles. Anyways, I attempted the blow out yesterday and had some issues. I attached the Cyclone blower at the inlet in my skimmer next to the pool and turned my Praher valve handle towards the pump, so that all 3 ports were open. My wife then turned on the pump and after a few minutes one of the return jets started blowing air, which I let go for a couple of minutes then plugged it off. Then my second return jet started blowing air, which I plugged after a couple of minutes. After a couple of more minutes, the main drain started blowing air as expected and after a few minutes of purging, I closed the valve to the off position (handle away from the pump, closing all 3 ports) and my wife turned off the blower. This in theory should have created an air lock on the main drain and to this point things were going smoothly.

    At that point, removed the drain plug from my heater, the drain plug from my cartridge filter housing, and moved down to the pump to remove the 2 plugs from it, when I noticed water slowly entering the pump housing from the intake side. Please note that my pool actually sits at a higher elevation than my pool equipment and with the Praher valve in the closed position for all 3 ports, water was slowly re-entering, so the valve appears to not be sealing properly. I tried fine tune adjusting the valve, but it would not seal off fully in any position. From what I have read, this particular valve is supposed to be maintenance free and it's only 1 year old, so I'm not sure if it's defective or if I'm doing something incorrectly. My wife is hunting down a packet of materials pertaining to all of the components to our pool system to see if it may be under warranty, but if I can avoid having to deal with the owner of this particular pool company again, that would be great. Any thoughts as to why the valve is not sealing? Again, when the handle is pointing towards the main drain, it should be closing the skimmer port, but water still draws from the skimmer. When the handle is in the fully closed off position, water slowly re-enters the pump housing. Any thoughts?

    - - - Updated - - -

    Hey guys, sorry for the duplicate thread. I typed the first thread, but was not logged in, so when I logged in it appeared as though what I had typed was lost. I then proceeded to create a second thread (this one) to ask my questions. After creating this thread, I noticed in my profile that both threads had been submitted. Not sure how to delete one of these threads......sorry.

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    gtemkin's Avatar
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    Re: Praher Valve is not holding an airlock on main drain after blowing it out?!?!

    Not specifically familiar with the Praher 3-way valves but here's some thoughts.

    1. Most 3 way pool valves close only a single port at a time, so the position that you say has all ports closed I think is actually not closing any ports. Look at the picture I've embedded of the Jandy 3-way and you can see the port blocking vane is only 1 port wide and it's always opposite the handle. Suspect the Praher is the same.

    2. Pool valves are called diverter valves because they direct flow but are not particularly good at sealing against pressure. I noticed one of the specs for the Praher valve is called "Positive Seal Backpressure" and it's rated at 15psi. The weight of 4 feet depth of water will develop a pressure of over 16psi so if your pool is above the height of your valves by 4 feet it's not a surprise the valves leak. I think this is a case where check valves with effective sealing at pressure would be used.

    Jandy_never_lube_3way.jpg
    21K gal 16' x 40' in-ground pool built 1959, old school with Jacuzzi bronze pump, American Products 24" Sand Filter & Americana Multiport valve, Jandy Lite2 millivolt heater, Coverstar cover, and classic Kreepy Krauly.

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    Re: Can't get main drain air lock to hold with Praher 3 port valve?!?!

    Thanks for the reply. I totally had a brain fart on this. With the handle pointing towards the pump, I understood that all 3 ports were open. I have no idea why I had it in my mind that when it was turned away from the pump, everything was closed, when only the port to the pump would be closed. The picture helps a lot. Now let me ask a couple of more questions if I may. Lets assume that if there were no problems with sealing pressures due to elevation differentials, then I could (in theory) blow out the main drain and then turn the handle towards the skimmer port to close off the main drain port and this should create an air lock. Correct? I was turning the handle until it was pointing away from the pump port, which closes off the pump port, but opens back up the main drain allowing water to back flow into the skimmer port as well and breaking the air lock. Now the problem I'm up against is that even in this position (handle pointing away from the pump), the blocking vane would be sealing the pump port and water should not be re-entering the pump chamber.

    So now this means that either the back pressure is too high causing it to break the seal or the diverter valve has a bad seal in it. Do these valves have seals that can go bad? Last year, the company that winterized the pool was able to do so effectively without having water back flow into the pump housing. When I opened the pool up, the pump chamber was bone dry, so last season the pressure differentials didn't seem to be an issue for them. Does this mean that the valve could be defective in some way. I ask this because as mentioned in my original post, when I was draining the pool below skimmer level, I had the pump handle pointing towards the main drain, which would position the blocking vane over and closing the skimmer port while keeping the main drain and pump ports open. Even in this position the skimmer was still drawing in water, so to me it seem like maybe the valve has a bad seal (if that's possible). Also, as I mentioned our vacuuming suction declined throughout the season, so maybe when we were pointing the handle towards the skimmer/vac port the main drain was still drawing in water too causing us to have less vacuum suction? Like I said, they were able to get an adequate air lock on the main last season and now I seem to be having an issue with fully closing off any of the ports with the valve. Thankfully, here in Michigan we are having a warming trend in the weather to give me more time to figure this out, but this kept me up all night last night. Any additional thoughts?

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    gtemkin's Avatar
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    Re: Can't get main drain air lock to hold with Praher 3 port valve?!?!

    I don't have any experience winterizing - only gets barely below freezing for a week here in Seattle - but I thought folks plug skimmers and returns in addition to closing valves. hopefully someone with more knowledge on that subject will come along and help you.
    21K gal 16' x 40' in-ground pool built 1959, old school with Jacuzzi bronze pump, American Products 24" Sand Filter & Americana Multiport valve, Jandy Lite2 millivolt heater, Coverstar cover, and classic Kreepy Krauly.

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    Re: Can't get main drain air lock to hold with Praher 3 port valve?!?!

    Yes, the both returns are already blow out and plugged. After creating the air lock on the main drain, then some antifreeze is poured down the skimmer and it's plugged as well. I haven't gotten to that phase yet with my valve acting up, so yes I am aware that those need to be plugged in addition to airlocking the main. Thanks.

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    gtemkin's Avatar
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    Re: Can't get main drain air lock to hold with Praher 3 port valve?!?!

    The only explanation I can come up with is the valve is leaking, however you may have been just lucky last year and your expectation that it work this year just because it worked last year may be unreasonable based on the engineering specs for the valve. If you want a sure and certain main drain seal, you'd want to install a ball valve in the main drain line that would be a positive shutoff.
    21K gal 16' x 40' in-ground pool built 1959, old school with Jacuzzi bronze pump, American Products 24" Sand Filter & Americana Multiport valve, Jandy Lite2 millivolt heater, Coverstar cover, and classic Kreepy Krauly.

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    Re: Can't get main drain air lock to hold with Praher 3 port valve?!?!

    From all your explanations it would seem that the valve is leaking by. Those valves can be rebuilt so I'd take it apart and visually inspect it for any wear.

    Just as a correction 2.3 feet of water = 1 psi, so it'd take 34.5' H2O to equal 15 psi.
    Dave J. TFP Moderator
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    Re: Can't get main drain air lock to hold with Praher 3 port valve?!?!

    Thanks, I just noticed the online calculator I used displayed total pressure - it included 1 atmosphere of pressure (14.69psi) in addition to the water depth contribution. Thought the value seemed real high.
    21K gal 16' x 40' in-ground pool built 1959, old school with Jacuzzi bronze pump, American Products 24" Sand Filter & Americana Multiport valve, Jandy Lite2 millivolt heater, Coverstar cover, and classic Kreepy Krauly.

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    Re: Can't get main drain air lock to hold with Praher 3 port valve?!?!

    When you started to blow out the pool, the valve should have been put at the setting that allows flow both to the skimmer and returns.

    When air is pushed into the lines at that setting, each line will clear on its on. All's you need to do is plug each one as it starts to spit and blow air.

    The order they clear will be, the skimmers blow first,plug them , then the returns, plug them and the last is the main drain.

    When the drain bubbles, that's when you turn the Handel on the valve so that the off postion is on the drain side of the pipe. That will create a airlock in the pipe.

    When you blow through the skimmer, that works as long as you understand that you need to get the water out of the most critical part of the pipes. The pipes that run to the pump.

    That's why I always blow through the pump and not the skimmer.

    You can use your blower the same way, just remove the pump and blow through that same pipe and do what I said above. Make it easy on yourself.

    For safety and a backup airlock. After you remove you blower , you can put in a rubber plug with a thumb nut in that same pipe and have a second means of a airlock.
    19,000 gal - Vinyl IG - Sand filter -1.5hp. - Taylor k 2006 - Loop Loc cover

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    Re: Can't get main drain air lock to hold with Praher 3 port valve?!?!

    Just a quick update. I had my doubts that the owner of the company that installed my pool would send his guys out to explore the problem, but he did. His guys showed up yesterday and indicated that these valves typically don't fail after one season, but they have seen a few of this particular brand (Praher 3 port) have seal issues prematurely. Based on this, the owner didn't charge me for the service call or the repair. The technician removed the handle and the top of the valve assembly and then quickly plugged the main drain port to inspect the seals. He showed me the blue seal on the diverter paddle and it was missing about 1/3 of the seal. He had a new valve and simply swapped out the guts of the new one into the existing housing. He indicated that there is a possibility that the back flow pressure combined with general use may have dislodged the rubber gasket seal, but he has seen the same thing happen with a couple of other pools this season where the equipment is not lower in elevation than the pool. Regardless, he said that he would come back in the spring and add some ball valves to the intake side of the plumbing as a precautionary measure when he is out in my area.

    The technician was also nice enough to blow out the main drain for me to show that it would hold an air lock and proceeded to review with me their step by step procedure in closing these fiberglass pools. They use the exact same Cyclone blower that I purchased and he asked me my procedure on how I was planning on blowing out the system. Although my plan works, he showed me a much easier way. I still hook up the blower to the skimmer next to the pool, but I should blow out the main drain first with the diverter handle pointing away from the pump, so that the air flow goes to the main drain only from the skimmer (not through the pump to the rest of the system). Once the main drain starts blowing, I then twist the valve handle towards the skimmer port to create an airlock. Next, I pour anti-freeze down the skimmer inlet, hook back up the blower, turn it on, then open the valve as prior (handle away from the pump) to push the antifreeze into the main drain. Once you see the anti-freeze first start entering the pool as the main drains are blowing, you quickly turn the handle back towards the skimmer to create the final air lock, with some anti-freeze in the lines.

    At this point, he pointed out that I do have a check valve below my heater, which prevents water from back flowing from the return jets, back into my equipment.....had no idea that it was there. He said to then drain the equipment by removing the plugs from the pump, filter housing, and heater, as well as disconnecting the plumbing at the base of my UV unit. Then reconnect the UV plumbing, but leave the plugs out and turn the blower back on at the skimmer to blow all of the additional water out of the components. Once only air is exiting, turn the pump back off and put the plugs back into the components to start sending air only through the check valve at out of the jets. He mentioned that by draining the components first, there is much less resistance and the blower has to work much less to get the job done. Once the return jets are blown out and plugged, then all of the drain plugs are removed on the components. Finally, you dump another gallon of anti-freeze into the intake of the skimmer and plug it, then put some anti-freeze into the skimmer housing and an empty anti-freezer bottle with some sand in the bottom to weight it down.

    His advice was very helpful and I was able to follow the procedures to quickly finish the job last night. The tech was awesome, so I gave him a nice tip for his time. The owner of the company may have been a jerk during the construction process, but his service folks are top notch!

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    Re: Can't get main drain air lock to hold with Praher 3 port valve?!?!

    If your pump, heater and filter are lower than your pool, how did they get the water out of the pipes from the skimmer to the pump if they blew through the skimmer?
    19,000 gal - Vinyl IG - Sand filter -1.5hp. - Taylor k 2006 - Loop Loc cover

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