air hiss from multiport valve

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borjis

borjis

LifeTime Supporter
Aug 19, 2014
3,612
Pacific NW
When I turn my pump off, I can hear a hiss coming from the multiport valve.

I thought it might have been the spider gasket, but I can actually here it coming
from a "black plastic bolt" that is mounted near the sight glass. (in the round area of the body next to)

There appears to be some sort of rtv sealant around the bolt threads.

This bolt is not shown in the blow up diagram of the sta rite wc212-150p multiport valve though.

Is this normal? or should I try finding the exact air leak area and put some rtv over it to seal?

and on a related note, whenever I switch to waste, water drips out where the sight glass goes
in to the assembly. How do I get it loose to replace the seal without breaking it? It's really in there tight.
 
Hi,
if you think you might have an air leak as you describe, you can put soapy water on it to confirm. If you have a air leak, the soapy water will bubble where the air is leaking from.

It behooves me though why there might be an air leak like you describe in that area.
 
Ya I was going to put a little shaving cream on it to see exactly where the leak hole is.

so the multiport valve should not be leaking any air at all when turned off correct?
I thought the bolt maybe was some sort of relief.
 
I'm not sure what the bolt is. A picture would help.

The spider gasket is probably leaking. When the pump is off, water in the filter tries to fall back down to pool level creating a suction. What you hear is air being sucked in from the waste line. The multiport might or might not be dripping to waste when the pump is on.

The sightglass is probably missing the gasket, which is why it leaks. You could try warming the area with a hair dryer to see if that loosens the glass. You could try a rubber jar opener or a strap wrench to remove the glass. Be careful not to over stress the glass as it could break. A garden hose gasket will usually fit. Adding a little bit of silicone lube (not sealant) can help make a better seal and makes it easier to remove the glass later, if necessary.

I'm guessing that the waste line is hard plumbed making it hard for you to see if there is water dripping out during pump run time. If it is hard plumbed, the bolt might have been added as a vacuum breaker to allow the line to drain when the bolt is removed.

Do you have an in-line tab feeder?
 
The sight glass didn't leak until the winter time when I would backwash. I'm doing a partial drain
now to get my CYA in check and had to put a bucket underneath the catch the drips.

no in-line tab feeder.

here is the "bolt" that hisses, It almost looks like a set screw / grub screw, as if to hold something
inside the assembly in place. definitely shouldn't be hissing or leaking though I imagine.

View attachment 34444
 
hhmm so it looks like my multiport valve is actually a sta-rite sp-715-2srw. wierd that it's labeled twice and differently.

any hoo, the schematic for this calls it a "polly plug" and its purpose is for draining the valve for winter.

I'll seal it up with some rtv.
 
It's a drain plug. It's a standard 1/4" pipe thread plug. You can remove it and reseal it with teflon or thread sealant. However, be careful not to put it in too tight as the valve can crack there very easily.

There could be air getting into the filter during operation due to a suction side air leak and the air is coming out. It could be related to the solar draining when the pump is turned off. It could be due to suction due to water trying to drain out of the filter back to the pool.

The SP-715 number is a Hayward number. It's probably a Hayward valve.

Since the hiss is coming from the drain plug, it's less likely that the spider gasket is leaking. However, it wouldn't hurt to check. If sealing the drain plug solves the problem of the hiss, that might be all there is to it.
 
thanks James.

I do actually have a small suction side leak...a little bit of air is streaming in when the pump runs (in the pump basket) and
air bubbles "blup" in from the suction inlet when I turn it off. Another small issue I'll address soon.

Thanks!
 
Good Day, this is John the Hayward tech. Could be a bad spyder gasket causing a leak from the waste line. I have seen this. I will private message you and you can call me as I have a bunch of questions. We can solve this problem.
 
Thanks John, I figured it out.

It was not the bolt that was hissing, it was the sight glass, which makes sense as it
would drip water during any backwash or waste operations.

I was able to re-seal it and now the hiss is gone and the pump/filter system is
holding it's vacuum quite nicely.
 

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JamesW said:
It's a drain plug. It's a standard 1/4" pipe thread plug. You can remove it and reseal it with teflon or thread sealant. However, be careful not to put it in too tight as the valve can crack there very easily.

There could be air getting into the filter during operation due to a suction side air leak and the air is coming out. It could be related to the solar draining when the pump is turned off. It could be due to suction due to water trying to drain out of the filter back to the pool.

The SP-715 number is a Hayward number. It's probably a Hayward valve.

Since the hiss is coming from the drain plug, it's less likely that the spider gasket is leaking. However, it wouldn't hurt to check. If sealing the drain plug solves the problem of the hiss, that might be all there is to it.
Click to expand...

I've never seen a multiport with a "drain". What it looks like to me is someone replaced a bad pressure gauge with a plug.

Does this plug leak water when the system is running?

If it were me, I'd pull the plug out and wrap it with teflon tape. When you put it back in, snug it by hand, then go a quarter turn more with a wrench. Either that or replace it with a pressure gauge.
 
It's quite common for that plug to be there. It's shown in the parts diagram. I would leave it alone if it's not leaking. That spot is weak, and any unnecessary stress can crack the valve.

It might not necessarily be a drain plug. It might just be a plug for valves the don't use a pressure gauge on the valve. Most likely, there is a pressure gauge somewhere else.

I think that the multiport spider gasket is probably leaking allowing air to flow from the waste line into the filter. If the waste line is hard plumbed with a check valve, that could prevent air flow back to the filter.

If the waste line is hard plumbed, I would suggest checking for leaks.
 
JamesW said:
It's quite common for that plug to be there. It's shown in the parts diagram. I would leave it alone if it's not leaking. That spot is weak, and any unnecessary stress can crack the valve.

It might not necessarily be a drain plug. It might just be a plug for valves the don't use a pressure gauge on the valve. Most likely, there is a pressure gauge somewhere else.

I think that the multiport spider gasket is probably leaking allowing air to flow from the waste line into the filter. If the waste line is hard plumbed with a check valve, that could prevent air flow back to the filter.

If the waste line is hard plumbed, I would suggest checking for leaks.
Click to expand...

I don't see any reason to assume there is a leak at the spider gasket. The plug is covering a port that is under pressure when the system is running. When you turn the pump off, the water in the system is going to want to run back to the level of the pool. If the multiport is higher than the level of the pool, there will be a vacuum inside that multiport. If that plug is leaking, it will pull air into the system, and you will hear a hiss.

Start with the easiest fix first. Remove the plug. Clean off any RTV. Wrap the plug with teflon tape, and reinstall the plug. Go hand tight, then about a quarter turn with a wrench. If it leaks, go an eighth of a turn at a time until it stops. Don't over tighten it, because it doesn't take much to crack plastic.

Chances are that the RTV on the plug is there because it leaked in the past, and someone just gobbed on some silicone instead of fixing it right.

As I reread this thread, I noticed the question about removing the sight glass. The sight glass should easily unscrew from the multiport. If it doesn't come out easily you can try wrapping a rubber band around it, or even one of those rubber sheets they sell to help open jars, and see if that helps you grip it any better. If that doesn't work, I would say to wrap a rag around it and try to turn it with channel locks. DO NOT squeeze down on the channel locks. Only apply enough pressure so that they don't slip.
 
It looks like the waste line is hard plumbed. If that's the case, then it might not be possible to see a drip to waste.

When the pump is on, the diverter is pushed down onto the spider gasket, which increases the seal. When the pump is off, the suction reduces the pressure of the diverter on the gasket. Also, air can slip by some weak spots that will hold water.

Therefore, even though it's unusual, there can be an air leak with the pump off, but not have a water leak when the pump is on.

In any case, the poster says that they hear the air leak at the waste line.
 
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