Air in filter but nowhere else

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ChrisJR

Air in filter but nowhere else

Postby ChrisJR » Wed 16 May, 2018 14:11

Hi, I have a 12-year-old Triton II TR-60 Sand Filter with a Pentair SM10-3 MPV. After opening this year, I purge the air from the sand filter, and when I come back to check in a few hours there is quite a bit of air in the filter, I have to bleed it off again. If I let it run all day, then bleed it, it is apparently full (or 1/2 full, as it is 1/2 full of sand) of air. I did some research and it sounded like it could be the spider gasket. I did a test, I ran it on recirculate and there were a ton of air bubbles then coming out the return line. I put it back on "Filter" and no bubbles out the return line, but the filter again fills up with air. There are no air bubbles evident on the suction side that I can tell, I have resealed the pump basket gasket, I don't see any air in there. Last year I had that problem, it was a cracked PVC inlet fitting, this year it is a different problem.

Thank you for any expertise you can offer.


Teapot
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Re: Air in filter but nowhere else

Postby Teapot » Wed 16 May, 2018 16:22

Sounds like air is getting in, have you looked at the gasket in the triton lid?
Denniswiseman
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Re: Air in filter but nowhere else

Postby Denniswiseman » Wed 16 May, 2018 16:34

The fact that a ton of bubbles came out of the returns when on recirculate indicates that there is a suction side air leak
Does the water level come 1/2 to 2/3 up the skimmer door or is the weir door jammed up
Check and lubricate the pump basket O ring and drain plugs in the pump
Teapot
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Posts: 481
Joined: Tue 17 Oct, 2017 10:52
My Pool: 12 x 24 (45m3) liner pool, Triton TR60 filter with AFM glass media (Activate) and variable speed pump running 0.08HP
Location: UK

Re: Air in filter but nowhere else

Postby Teapot » Wed 16 May, 2018 16:43

Quite true Dennis, I think I would also stick a bung into the backwash waste pipe and see what happens.
ChrisJR

Re: Air in filter but nowhere else

Postby ChrisJR » Wed 16 May, 2018 21:06

My pool is a bit of a hack job, when I bought the house 14 years ago it came this way - the original pipes must have froze up, so the prior owner abandoned them and put in all above-deck PVC. There is an intake hose that runs from PCV on the deck to a plastic thing on the bottom of the deep end. Looks like it was made from a plastic pail bottom with holes in it and a plastic panel on the top and some lead weights to keep it down. Anyway, my point is, I have no skimmer. Does anyone have an opinion on the source of the air leak being the internals of the multi-port valve, esp the spider gasket or similar? It seems remarkable to me that on recirculate the air flows through quite readily, but on regular filter mode it only gets as far as into the filter tank, it does not seem to get through the sand and back to the pool. I seem to recall a few years ago running it on recirculate for a few hours and I came back and had lost several inches of water. So I have not used recirculate since then (until doing this test today).

I have checked and lubricated the o-ring in the basket, but not on the pump yet. I will look at those.
Teapot
Swimming Pool Superstar
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Posts: 481
Joined: Tue 17 Oct, 2017 10:52
My Pool: 12 x 24 (45m3) liner pool, Triton TR60 filter with AFM glass media (Activate) and variable speed pump running 0.08HP
Location: UK

Re: Air in filter but nowhere else

Postby Teapot » Thu 17 May, 2018 02:31

Teapot wrote:Quite true Dennis, I think I would also stick a bung into the backwash waste pipe and see what happens.
Denniswiseman
Swimming Pool Superstar
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Posts: 997
Joined: Tue 06 Sep, 2011 05:48
My Pool: 10k inground fibreglass, Telescopic Cover, Hayward Powerline pump, Quality filter with glass media, 27kw output heat pump, K-2006C test kit
Location: United Kingdom

Re: Air in filter but nowhere else

Postby Denniswiseman » Thu 17 May, 2018 02:34

The MPV is under positive pressure and will only leak water while running not sucking in air
If you lose water on recirculate the spider gasket could be at fault if the backwash outlet is plumbed direct to waste and you don't see any water leaking
When you have air in the filter do your returns still work satisfactory?
Teapot
Swimming Pool Superstar
Swimming Pool Superstar
Posts: 481
Joined: Tue 17 Oct, 2017 10:52
My Pool: 12 x 24 (45m3) liner pool, Triton TR60 filter with AFM glass media (Activate) and variable speed pump running 0.08HP
Location: UK

Re: Air in filter but nowhere else

Postby Teapot » Thu 17 May, 2018 03:25

A bad spider gasket can also cause a venturi effect to draw in air from the waste pipe.
ChrisJR

Re: Air in filter but nowhere else

Postby ChrisJR » Thu 17 May, 2018 08:13

Yes, the (single return in my case of the above-deck PVC) still works fine when there is air in the filter tank, it is just as robust as ever.

I will try the bung in the waste pipe, or perhaps install a ball valve. Right now the waste pipe is "hard-wired" into a plastic pipe that disappears underground and emerges again at the property line, so either way I'd need to cut it.
ChrisJR

Re: Air in filter but nowhere else

Postby ChrisJR » Thu 17 May, 2018 09:27

Correction, the waste line has a short piece (6") of plastic tubing that is then clamped to a 90 degree elbow that connects to the plastic pipe that disappears underground, so I can check that clamping and/or unclamp it and put a bung in.

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