Hayward sand filter leaking sand

[everthustodeadbeats]

A couple days ago I noticed some sand on my driveway where the backwash exits out to. That's weird, I thought. Sometimes I see dead algea or other debris that came out in a backwash, but never sand. Then today the plumbing started leaking from multiple places, basically everywhere there is a union or anything with an O-ring, including in a check valve. I opened the union going into the heater and the O-ring is covered in sand, no wonder the seal was failing. Then I noticed the sight glass on my multiport is filled with sand, and when I went to turn the multiport to backwash I heard and felt it creaking and crunching, like it's filled with sand.

What is going on, why is my filter spitting out sand out of every orifice? Is this an issue of just changing a failed O-ring somewhere in the filter (or maybe in the multiport? I did just take out and reinstall the multiport for maintenance recently), or is this a more serious (read: expensive) issue? And how should I flush out and clean the rest of my equipment, like my gas heater, that has already gotten sand into it?

I have a Hayward S310S side mount filter and a Hayward SP0715X62 Vari-Flo multiport valve.

 

[Texas Splash]

During your maintenance, did you happen to open the MPV to inspect the spider gasket/diverter? That could be the issue.

 

[everthustodeadbeats]

During your maintenance, did you happen to open the MPV to inspect the spider gasket/diverter? That could be the issue.

No, didn't touch that. It was actually more of a repair. There was a hairline crack in the output port threading (possibly from over tightening) that was leaking. I patched it up with epoxy and glue and covered it with a hose clamp. I tried to do what this guy did ---

--- but I didn't do as good a job. It still leaks a tiny bit, but it's much better.

In any event, no, I did not take apart the valve at all, I was just adding epoxy to the exterior.

However, this was the first time I ever detached the multiport from the sand filter itself. When I reattached it to the filter, one of the unions (I think it was the bottom one) was leaking. I took it back off and saw that the O-ring was stretched and misshapen. I bought a new O-ring for that union, screwed it back onto the filter, and it seemed like it was working fine, no leaks. That was about 2 weeks ago.

 

[Texas Splash]

The condition of your MPV might be a bit tricky due to the crack encountered from overtightening. Do you happen to have a pic of that cracked area? I might see if we can get @1poolman1 to comment on that repair process.

 

[everthustodeadbeats]

Also, while on the one hand it does seem like the multiport is the weak link in this equation given the recent activity, on the other hand how could any issue with the multiport cause sand to come out of the filter in the first place? Even if the multiport valve were totally broken internally, how would that change what's flowing into the valve from an external source (the filter)? Doesn't the fact that sand is exiting the filter into the inlet port of the MPV indicate that the problem is on the filter side?

 

[Texas Splash]

how could any issue with the multiport cause sand to come out of the filter

You have a good point in that sand "shouldn't" be able to just travel through the MPV, but I recall other owners who had unusual occurrences when the MPV went bad, either structurally or internally. For some more field examples and explanations I would defer to @1poolman1 when he has a chance to check in with us on the forum.

 

[everthustodeadbeats]

If an MPV can cause sand, then could the spider gasket or other innards of the MPV have gotten bounced around just from my handling of it, even if I nevered opened the valve?

I also thought of another candidate for the culprit:

I am in the middle of trying to put up a solar heater (I have another thread on that). In anticipation of the finished product, thus far I've added a return check valve to the plumbing after the MPV - this is for water coming out of the solar heaters going back to the pad. Right now there is nothing on the other side of the check valve (the supply side), but when the pump is running it works and stays closed. However, when the pump turns off it opens and sucks up air bubbles into the plumbing - it's one of those gravity-flap ones; there's no spring keeping it closed. I didn't think that was a problem (it loses a little prime sure, but it starts back up again fine), but maybe this is causing backflow into the filter? Is sand in the pool a sign of backflow?

Photo of the check valve in question is in that other thread I mentioned. Direct link to image: Pool pad.jpg

 

[everthustodeadbeats]

Another unusual occurance: A couple days ago I accidentally left the backwash on for too long (about 45 minutes). I was kicking myself because of all the wasted water, but could that also have contributed to sand escaping? Is there such a thing as too much backwash?

 

[Texas Splash]

but could that also have contributed to sand escaping?

Sure

 

[1poolman1]

A couple days ago I noticed some sand on my driveway where the backwash exits out to. That's weird, I thought. Sometimes I see dead algea or other debris that came out in a backwash, but never sand. Then today the plumbing started leaking from multiple places, basically everywhere there is a union or anything with an O-ring, including in a check valve. I opened the union going into the heater and the O-ring is covered in sand, no wonder the seal was failing. Then I noticed the sight glass on my multiport is filled with sand, and when I went to turn the multiport to backwash I heard and felt it creaking and crunching, like it's filled with sand.

What is going on, why is my filter spitting out sand out of every orifice? Is this an issue of just changing a failed O-ring somewhere in the filter (or maybe in the multiport? I did just take out and reinstall the multiport for maintenance recently), or is this a more serious (read: expensive) issue? And how should I flush out and clean the rest of my equipment, like my gas heater, that has already gotten sand into it?

I have a Hayward S310S side mount filter and a Hayward SP0715X62 Vari-Flo multiport valve.

A leaking spider gasket won't allow that much sand (if any) into the rest of the system.
Possibly a broken lateral. That's the most likely (only?) way for sand to get out of the filter into the return portion of the system. It will first fill the MPV then just flow wherever the plumbing leads it.
For all joints that are sealed with an O ring to be leaking, it sounds like the system was overheated. The heater may have to have the manifolds removed to clear them and the heat exchanger out. Don't know which heater is in the system.

 

[everthustodeadbeats]

For all joints that are sealed with an O ring to be leaking, it sounds like the system was overheated.

The O-rings were leaking because they were filled with sand, breaking the seal.

Interestingly, while the sand seemed to get everywhere in my equipment and plumbing, I didn't much if any sand in the pool itself.

 

[1poolman1]

The O-rings were leaking because they were filled with sand, breaking the seal.

Interestingly, while the sand seemed to get everywhere in my equipment and plumbing, I didn't much if any sand in the pool itself.

If your pool is like most, unless you have an SWG, the heater is the last item in the plumbing before the pool itself. Sand could be collecting in the heater and not making it out. If its in the heater, it will make it to the pool. Best I can guess from 2000 miles away.