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Thread: Leak on Whisperflo pump outlet pipe

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    Leak on Whisperflo pump outlet pipe

    Hi folks,

    I've searched the forum and didn't find a thread that covered this situation, so if there is one... please forgive my lack of search skills...

    I have a Whisperflo which I managed to run blocked in for a couple hours inadvertently. I had closed the filter valve and forgot... felt really stupid that I started the pump and didn't realize that was going on. Anyway... it got hot, and the o-ring on the pump case as well as the outlet piping developed a leak. I've replaced the o-ring, but the pipe is a different story.

    The builder hard-piped everything from the pump to the filter... I have no unions or obvious threaded connections.



    There are no threads visible on the discharge pipe. All I found was some sort of flexible sealant around where it came out of the pump, and this was dripping.



    I consulted my local pool supply company and they sold me some silicone sealant, which I applied and let cure for 24-48 hours. I was dubious about that approach because I didn't think applying it to the outside of the pipe joint was likely to be enough to keep the water pressure from pushing through. When I restarted the pump it still dripped...

    What are my options? I was intending to use an exacto knife and try to remove all exposed sealant, because I think I didn't get complete covereage when I resealed it. I could also use some sort of solvent to try to get further down in the joint. However, I am still skeptical that this is going to stop it from leaking. Seems like I need to disconnect the piping and reseal the joint like I would a typical threaded plumbing connection. Am I going to need to get the hacksaw after this piping?

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    Agent99's Avatar
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    Re: Leak on Whisperflo pump outlet pipe

    So it looks like you developed a leak at the pump to nipple interface there? That connection to your pump is a threaded connection so it can be unscrewed but that will entail some cutting of pipe.

    What you have there is a threaded plastic pipe/nipple with (likely) 2" pipe threads. Pipe threads are tapered. Odds are EXCELLENT that the pump has 2" STRAIGHT threads. Now the two are compatible and will secure to each other fine and can even be sealed fine (with pipe dope and/or teflon tape) but sometimes they will leak no matter what you do. That pump was designed to take a union with straight threads on it. This union will also have an o-ring on the outside that seals against the pump body (this is how you know the union is also straight-thread...tapered fittings/threads do not require an o-ring). You want a union like this: Amazon.com: 2 PACK -CMP Hi-Temp Union 2 Garden

    What likely happened was that the various plastic elements around the pump got hot and expanded and perhaps even out of shape so that you are no longer sealing well once cooled down.

    I'd cut out all the pipe to that long pipe that heads to your filter and redo all the plumbing there with a (correct) union for the pump. However, with careful cutting, you might be able to keep all the plumbing and just cut that black nipple the correct length and get a union on the pump and then slide it back under the black nipple to glue it to the union. You probably have reasonable flex in that line to do this but it isn't the end of the world to just replace that small section of plumbing if you need to.

    And since you're getting TWO unions (if you take my advice), you might as well put a union on the pump INTAKE as well. This will make future work much easier on you should the pump need to come out for some reason.
    ----Chris----
    25k IG/Spa Figure 8, 18x36, Pebble Sheen Blue Granite, Sta-Rite S8M150 Cartridge Filter, Pentair 460805 400k BTU Heater & 011018 IntelliFlo VarSpd
    Liquidator, Fafco Solar Heat, Polaris PB460 Booster Pump w/280 cleaner, Katchaleaf Cover, TF100 Test Kit, FAKE MAIN DRAIN

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    Re: Leak on Whisperflo pump outlet pipe

    Thanks for the feedback. Here's what I've done... going to let this cure for a couple days then see if it holds. Not optimistic, but it's the cheap solution on a Saturday full of college football...

    Cleaned off all the sealant...



    Used this stuff to reseal...





    I'm sure it all got quite hot... here's what the hair strainer basket looked like. It's cheaper than the OEM, made of some sort of lower strength plastic (PVC vs. PE)... nonetheless, obviously got hot.



    I'm going to let this cure and see what I get. The PVC piping likely didn't warp as much as the PE, but it doesn't take much to open up clearances.

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    Agent99's Avatar
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    Re: Leak on Whisperflo pump outlet pipe

    Yep, things done got toasty hot!!! I hope your sealant works or at least slows things down so you can assess, perhaps, a more proper repair in the future...preferably after college football is done.
    ----Chris----
    25k IG/Spa Figure 8, 18x36, Pebble Sheen Blue Granite, Sta-Rite S8M150 Cartridge Filter, Pentair 460805 400k BTU Heater & 011018 IntelliFlo VarSpd
    Liquidator, Fafco Solar Heat, Polaris PB460 Booster Pump w/280 cleaner, Katchaleaf Cover, TF100 Test Kit, FAKE MAIN DRAIN

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    borjis's Avatar
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    Re: Leak on Whisperflo pump outlet pipe

    That silicone stuff won't likely keep a seal. On the suction side it probably would..but not on discharge side.
    16x32 IG Vinyl, 13,000 Gals. Hayward S-244T sand filter, SP2810X15 pump
    (1.5 HP motor) Raypak PR266AEN (266k btu) gas heater. TF-100 Test Kit.
    Dolphin E10 Cleaning Robot.

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