Is copper ok for the manifold?

I want to replace my 30+ year old galvanized supply line and manifold. I don't trust PVC in a situation where there is always pressure because I’ve had 2 PVC fittings (The fittings themselfs, not the connnection) blow apart in recent years in a PVC line I ran to a hose bib. The rest of my house has been re-piped with copper, and I was thinking of using copper for the new irrigation line and manifolds. Is there any reason not to use copper pipe?

When properly installed Pvc is good, been using it for 13 years and when cleaned and glued with good glue its there.

Lee Tanner said:

When properly installed Pvc is good, been using it for 13 years and when cleaned and glued with good glue its there.

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As I said, it wasn't the (glued) connection that failed, it was the fittings. One 45 degree elbow, and one 90 degree elbow. They just sort of split open in the middle. I just don't trust them for constant pressure usage after that.

JeffL said:

I want to replace my 30+ year old galvanized supply line and manifold. I don't trust PVC in a situation where there is always pressure because I’ve had 2 PVC fittings (The fittings themselfs, not the connnection) blow apart in recent years in a PVC line I ran to a hose bib. The rest of my house has been re-piped with copper, and I was thinking of using copper for the new irrigation line and manifolds. Is there any reason not to use copper pipe?

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Like this?

If you simply avoid using any female-threaded PVC fittings, with the notable exception of Schedule 80 unions, you will have no need to go all-copper. There are also some excellent paste dopes for plastic threads, that make tightening much less critical. Absent plumbing experience and skills, going all-copper is a good way to compensate for your DIY shortcomings.

By the way, the pictured antisyphon valves are your best choice for the job.

I don't think I have any DIY skill shortcomings in working on a sprinkler system. If I did, I would think PVC would be the better choice since it's easier to glue PVC than sweat copper.

Regarding the anti-siphon values; I started with manual brass Champion valves, and converted them to electric with plastic adapters. They lasted about 20 years, then I had to start replacing the adapters. The new plastic ones seemed to have problems after about 3 years, so now, whenever one needs replacing, I use a brass adapter.

Use whatever you want - just note that pros are not troubled by broken PVC fittings, and that a good antisyphon valve is serviceable forever.

Wet_Boots said:

note that pros are not troubled by broken PVC fittings, and that a good antisyphon valve is serviceable forever.

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I'm really not the argumentative type, but...

1. I just did a Google search, and found a web page article called "The perplexity of PVC-fitting failures" that deals with the pros having problems with PVC fittings: http://www.grounds-mag.com/mag/grounds_maintenance_perplexity_pvcfitting_failures/

2. As far as good anti-siphon valves being serviceable forever, I would have thought so also, but I recently had another problem. It was with one of my brass Champion anti-siphon valves that I put a brass actuator on. The anti-siphon valve was the first I installed, so was over 30 years old. The actuator was 2 or 3 years old.

After the system ran, the heads were bubbling like a fountain. I took the actuator off, and noticed a kind of deep grove from the seat in the seat washer. I replaced the washer, but a couple weeks later, I noticed water seeping out of the lowest head. I took it apart again, and this time the washer looked ok. I checked the Champion web page, and it said:

"If the valve seat in the anti-siphon valve body is worn out, there will be water leakage. Brass anti-siphon valves have a service life of anywhere from 5 to 10 years with many in service over 25 years. However, these valves can eventually wear out."

They should put replaceable seats in those things. To be honest, I still don't know if the problem was wear of the seat, or a problem with the actuator. I just didn't want to deal with it at the time, so I bought a complete new Champion brass valve with the brass actuator already attached. End of problem. Maybe I'll figure it out in the future. I saved the old parts, so I can test them when I have nothing else to do.

Argue all you want. When you've spent a few decades repairing the stuff, come back and revisit the topic. There's a difference between opening the cover of a diaphragm valve, making the repair, as compared to the replacement of an actuator assembly in a brass valve body. The article you linked repeats the essential point about PVC valve manifolds ~ "Female plastic threads on male metal threads are the most vulnerable to over-torqueing, so avoid them if possible." ~ edit that statement to "avoid them, period" and you have words to live by.

By the way, the plastic valves pictured above are based on the Richdel antisyphon valves, which have female-threaded connections that are slightly oversized, which will annoy the bejeezus out of anyone who fails to apply enough teflon tape (or plastic-approved paste dope) to the threads of the nipple or fitting that threads into them. For the price of said annoyance, you have a plastic valve body that doesn't a track record of cracking.

As far as seat wear (or sometimes just corrosion) goes, that can happen with brass valves. Plastic valves? Not an issue.

In the very long term, a possible issue with exposed PVC will be exposure to sunlight, which can result in brittleness.

One final possibility for having cracked PVC fittings, even if you did everything else correctly, is buying imported crap sprinkler/plumbing product from a big-box store, as opposed to American-made fittings from a supplier that has an interest in customer satisfaction.

copper for manifold

I have installed 100's of systems and many manifolds. You could use copper/You could use poly. I would suggest at least 160 psi poly with two stainless clamps might be cheaper than copper. Especially when you get into the 1" size.

PVC is way better and yes there are different levels of quality in pvc fittings

Lasco and Spears are the leaders and I think they are in the Big Chain stores.

I have had a fitting completely blow apart once, but I think it was my fault.



I use 725 or 721 glue which is pretty hot and if you over do it you can actually weaken the pipe or fitting.

Good Luck