Replacing old backwash sight glass

[ErniesPool]

I have an old Hayward sight glass with the 4 screws holding it together, and the glass (plastic) is so discolored I have a hard time telling when the water is running clear during a backwash.

Two questions:
a) It looks like to replace it I have to cut the PVC and replumb that part of the system to cement the new sight glass assembly in. It looks to me like cutting and installing a replacement is going to be very tricky, given you have to cement both ends at the same time. Is this a DIY job or better to hire someone who is adept at working with PVC?

b) Given a) above, why on earth does this assembly include a screw-in glass piece, as if you could replace just the glass? You can't as far as I can see. You have to replace the whole thing unless there is a way to install it with a compression couplings (I don't have room from that in my plumbing setup),

 

[Demegrad9]

What model hayward multi-valve do you have?

My sight glass just screws in, I'm surprised hayward made a multi port valve that has it glued in.

 

[ErniesPool]

The sight glass is not in the valve, it is in the backwash line to the P trap. It looks like this one:
https://www.amazon.com/dp/B0032GB6B6/ref=asc_df_B0032GB6B65490974/?tag=hyprod-20&creative=394997&creativeASIN=B0032GB6B6&linkCode=df0&hvadid=167151535350&hvpos=1o5&hvnetw=g&hvrand=7778343574066314149&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9026945&hvtargid=pla-309007613024

except mine has 4 screws instead of two. It is cemented into the line on both ends.

 

[JamesW]

Remove the screws and the glass pops out. Put in the new glass and reinstall the screws.

 

[ErniesPool]

I really can't see how that would work. The glass fits into channels in each end of the fixtures. With all screws out, one end or the other would have to be backed out 1/4" or more to remove the glass. How could that happen with both ends cemented in??

 

[JamesW]

There's usually some amount of slack where you can move the pipes.

 

[ErniesPool]

I don't think there is any play at all in my setup. The end on the right side of the picture goes right into the multiport, which is hard plumbed into the system. The other end has about a foot of PVC before it dives into the ground on the way to the trap. I think my only option is to cut the sight glass assembly out (O rings in it are shot as well as the "glass"), replace the L piece threaded into the bottom of the multiport, and use a short compression fitting on the other end to give me enough slack to glue the thing in and also at some point in the future maybe replace it. This solution is a lot of sweat equity and about $50 worth of parts.

Other option is to replace the multiport, which I just reworked by installing a set of O rings, and the pool guy says that is about a $1,500 job. Ugh.

 

[JamesW]

Remove the screws and see if the glass will pop out. I think you can push the left side at least 1/4".

Dig out around the pipe going into the ground to create some wiggle room.

 

[Demegrad9]

I don't know which multi-port valve, but I just bought this one:
Amazon.com : Hayward SPX0710X32 Side Mount Valve Replacement for Hayward Multiport and Sand Filter Valves : Swimming Pool Filter Valves : Garden Outdoor

Easiest install of anything I've done recently with my pool. Valve is ~120 bucks, took maybe 30 minutes to replace.

If you do replace the MPV, install unions coming straight out of the valve so you don't run into this issue in the future.

 

[ErniesPool]

James, you are right! Got the 3 screws out and was able to wiggle the multiport a bit to get it loose. May have cause a small leak that I can fix. Now for replacement. Thanks!!!!!!!!