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Thursday, April 8th 2010, 11:27am

Watts PVB

Last winter my Watts WA800M4QT 1" broke down after a hard freeze in Houston. Because of the sheer number of PVB that were damaged during the freeze, its been difficult to find replacement parts. So I'm thinking about just replacing the whole thing.

I know plumbing basics and have done a fair amount of repair work on my system (i.e. replacing connections, adding additional runs, etc.). My questions are...

1) The current one is hooked up with PVC from the ground. Is this appropriate (using PVC) and can I just cut off the unit currently in place and replace it with a new one?

2) The freeze we had was a fluke, but who knows what next year will bring. Are the freeze resistant models truly freeze resistant?

3) Do I even need a PVB for a residential install? I've got 5 zones running. I assume I do since I'm going into the main, but it sure would make things easier to bypass the thing all together.

4) I went to Sprinkler Warehouse a few months ago (since they are right down the street) to get replacement parts, but was told they don't carry parts for Watts (even though I saw them on the web site). Any suggestions on where I could go to get replacement parts for the one I have if replacement isn't a good option? I think it's just the white plastic float that broke.



Supreme Member

Posts: 482

Location: Houston, Texas


Friday, April 9th 2010, 10:53pm

In Houston, Plumbing supply houses carry watts and irrigation supply houses carry Febco, Wilkins, Conbraco. You need a Backflow preventor in Texas it is the law. It sure would be easier to do with out it. When was the easy way ever the right way?

Sorry about the preachy part. Just do it. Get a Replacement and 2 male adapters 1", 2 couplings 1", 1 90 1", and some good insulation for cold weather. When it freezes next time cover it with a towel, and some plastic, and drain the backflow for cold weather. I have not replaced one backflow preventor this year that somebody had protected from the freeze by draining the backflow and wrapping it in a towel and plastic. After you replace or repair the PVB, it should be inspected by a licensed Back flow prevention assembly tester.

Good Luck

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LI0006121, BPAT0011021, CI0009500


Supreme Member


Tuesday, April 13th 2010, 9:47pm

Getting rid of back flow preventer for irrigation would be like bypassing a circuit breaker that occationally trips on you. The PVB is a protection device, and as far as "residential"... that just means that (in many areas) you can get away with using only the minimum protection... the PVB. If you were commercial, then you might be required to move upto an RPZ (the mother of all backflows).

As for freeze protection, no such think unless the device is heated somehow. Otherwise, the only thing I can think that a freeze resistant model might do is use thicker materials so that it takes longer before the water inside freezes and can withstand the initial pressures of a minor quick freeze better... OR they are doing something to purge the water so that there is nothing to freeze. Otherwise, regardless of what someone tells you, you put water in a device and leave the device out in freezing temperatures, the water is going to eventually freeze and will damage the equipement (at least anything that could affordably be sold to a home owner). I wouldn't even consider a freeze resistant anything unless someone can explain EXACTLY how it works (without the smoke screen).

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