Automating sprinkler system winterization

[DC]

I'm considering fully automating the winterization of my sprinkler system this winter. I will run a permanent pipe from the compressed air system in my shop to the main feed line for the sprinkler system. There will be an electrically operated valve in that line. There will also be an electric valve in the water pipe from the well to the sprinkler system. To water, the air valve will be closed and the water valve will be open. When the outside air temperature drops to 32 degrees (the ground will still be a few degrees warmer) HS will:

1. Close the water valve.
2. Open the air valve.
3. Turn on the air compressor.
4. Set the air pressure to 50 PSI (instead of the 90-120 PSI I normally use for air tools in the shop).
5. Open the first valve in the system for 1 minute then close it for 2 minutes (to let the air compressor catch up)
6. Repeat step 5 for each valve in the system.
7. Turn off the air compressor.
8. Turn off the air valve.

The sprinkler system will then be completely purged of water. The only catch is that I have to find a remote controlled pressure valve that HS can set. Air pressure higher than 50 PSI can damage sprinkler system pipes and valves. Does anybody know of such a valve?

[smoothtlk]

You probably won't find an electric solenoid valve that will also have a pressure regulator in it. So, put a T in your main compressor line, on the HS controlled side, then put a regulator and set to 50 psi manually. Then, after the regulator, put the electric solenoid. Then, connect to your sprinkler system. I am wondering if a sprinkler solenoid could be used for air as well. Kinda doubt it. Anybody got experience here? Anybody know of a 12 volt solenoid for air that is cheap?

You bring up a good point of auto the winterizing. I won't use a hard lined air to sprinkler, but will instead just use a quick coupler, then use HS to automate the cycling and rest periods to open / close the water sprinkler solenoids. Please keep us posted on your progress. Which sprinkler relay are you using? Rain8net? Irrigation controller?

[huggy591]

I don't know if they still make them, but I recall there used to be check valves in air lines to keep liquid from backing into the line. That might be a good thing to use to make sure you don't accidentally fill your air tank with water...

[Rupp]

DC,
How does this blowout work? Is it simply a cap over PVC pipe just after the water feed? Or is it a screw type connection that the air hose connects to? My system has been in the ground for 10 years and I've never had a problem but if it's easy enough to add it would hurt to add. The water company just had to dig up my driveway and sidewalk and they didn't get the lines buried as deep as I would have liked and this would be good insurance.

[smoothtlk]

The air fitting goes inline into the manifold that feeds the solonoid valves. I have put a permanent air hold fitting on the manifold and just use a double ended male air fitting to air pressurize the system.

It displaces the water with air through the system blowing the water out the sprinkler heads. One shuts the water supply and then open a zone valve and apply air pressure. When the compressor runs out of stored air, close the zone and let the compressor build pressure again. Then, open the valve again to be sure to rid all water in the zone. Then, do all other zones same way.

Most do this manually, but it takes me about 2 hours to do all my zones. Would be nice for HS to command it all.

My water feed is a 2 inch line so automating the water shut off would be an expensive large solonoid. I have a gate valve on it now that I just turn down to shut the water supply off.

[DC]

Rupp, if your sprinkler lines are below the freeze level, they won't freeze. However, if your sprinkler valves are in valve boxes just below the surface they can freeze if it gets cold enough. But, you may be far enough south not to get a hard enough freeze for it to be a problem. It isn't a problem for me until the temp gets in the low 20's or teens for a couple of days straight. Also, it's possible to put drain valves in the lowest point of every line but that's a lot of work during installation because you have to dig a gravel sump at the end of each line for the water to drain into. One time about 5 years ago I didn't winterize my system and I had three pipes break because they still had water in them and water expands when it freezes. It was a big hassle the next spring to dig up and repair the pipes. Now, I always blow out my system manually just before the first freeze and leave it winterized until spring. Last year I "semi-automated" it by manually shutting off the water valve, connecting an air hose to a quick connect fitting I installed in the line, then had HS cycle through all the zones. This year I want to fully automate it as described above. One reason is because I have a pond and waterfall now that will need to be topped of every few days even in the winter and the sprinkler system does that automatically.

Gordon, yes I will put in a check valve. The air compressor wouldn't normally fill with water because it will be higher pressure (90-120 PSI) than the water system (40-60 PSI) but it could certainly happen if the air compressor is off and the residual pressure in the tank drops enough. I will put a check valve in just as an extra safety measure.

DavidL, you are right, I don't need an electrically controlled pressure regulator. I was thinking of putting that at the air compressor to drop the pressure in the whole system to a level that would be safe for the sprinkler system but that won't be necessary because I can just put a simple manual pressure regulator in the line that feeds the sprinkler system. Duhhh..... Also, I did just what you mentioned last year. I just ran an air hose from an air outlet in my shop and plugged it into a quick-connect fitting in the water line. To make it more permanent, I will either run a permanent galvanized air pipe into my water treatment room from my compressed air system, or I'll put a small compressor in that room and connect it permanently with a short air hose. Actually, I might go that route because I want a larger compressor in my shop anyway so that would be an excuse to dedicate my existing compressor to sprinkler system winterization! :-)

The electrically activated valve I would use is the WaterCop valve (http://www.watercop.com/watercop.asp) I would actually have to have two -- one in the water line and one in the air line. I would not use the wireless model, I would just get one that is hard-wired and operated by an Ocelot relay.

I will try to post some photographs or drawings of this when I get it working.

[Stevech]

Freezeline? air in the lines?
What are these concepts?????

Stevech
San Diego

[Rupp]

Ha! Ha! Stevech.
They are kinda like an EARTHQUAKE but not nearly as destructive.

[Stevech]

Earthquakes? We go no stinkin' earthquakes here. That's way north in Lost Angels, Calif.