We live in Saskatchewan Canada, where we have extreme winter. In fall season we have highly mixed days, sometime we have temperature around -6 after few days it could be +10/+14 and then down again but in extreme winter it can be as low as -30.

I'm very confused about fall season, should i drain my sprinklers for temperatures like -2, -4, or -6?
In that case after few days again i may need to water the grass and then winterize it again. or i do not need to winterize in temperatures like -6/-8?

 

Generally lawns go dormant around 6 celsius so watering below this temperature would likely be unnecessary. That being the case, I'd winterize once temperatures start getting close to freezing.

 

Anytime it gets much below 0, you risk having your back flow preventer (which is above ground) and surrounding pipe freeze and break. If you're not around when it thaws that could add up to a couple hundred thousand gallons. So it's not really something to mess around with. Wind makes it worse as it blows the heat of the house and ground away from the pipe, making it cool down faster as a result.
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If you have experienced freezing temperatures you don't need to worry about watering the lawn until next season. I would winterize once the nights get down to about 5c and absolutely winterize before you get the first freeze.

 

We have similar weather here in my part of Ontario.
What I have done with our sprinklers here (no one has said anything about my procedure so far), is about this time of year is turn off the water supply line, open all the zones one by one to release the pressure, then open the main drain valve and leave it open to air out. My thoughts are that the water should mostly drain/evaporate out, and yet still allow space for anything still in the lines to expand and contract with the change of temp.
Been doing this for 3 years now without issues so far. I do not know how old the system is as it was installed before we bought the house.

 

Wow, sounds like you have been lucky, Northern Mike. If ours aren't blown out with an air compressor, portions will explode. It's typical to have some pvc underground to a control box, plus all the plastic inside the control box. The poly lines are a little more forgiving.

 

Xsleeper,
What size of lines do you have?
I've never had nor looked into getting sprinklers before. This house just happened to have them.
The lines they used here almost look to be ABS, 1 1/4" diameter (based on memory). I remember they where huge as I had to repair a splice last year and couldn't find crimps large enough locally.

 

Supply lines are often copper leading up to the vacuum breaker, that transitions to 1 1/4 abs near ground level. Then the underground lines are usually 1" poly. Branches will often be 1/2" poly. But that's just the Rainbird system I'm familiar with at our congregation. I had to dig up 50' of swamp one spring when my dad didn't do it right, so I said never again and have blown them out myself every year since.

I just put a ball valve in the basement and then a spigot at the lowest point to drain it, a gate valve above that with an air chuck attachment. I cycle the lines 3x to make sure they are clean. Water runs backward when you quit blowing and collects in any dip in your line. That's why the 3x. Plus it makes me feel warm and fuzzy knowing I won't ever have to dig mud again.

 

thanks, but big problem is that once temperature falls below zero it can raise again and max temperature could be 10/14 in that case it looks like i should water the grass? if yes that is the point where question raises.
However what I understand its good/safe to winterize it in cold weather.

 

Going on memory, my setup sounds similar (no air connections however).
I'm going to guess I've been lucky with my setup.

 

sairfan1, I responded earlier but want to provide a thought on your post. I live in an area considerably warmer than yours and don't believe a few waterings more or less will have any substantive impact on a lawn. Conversely, a frozen sprinkler system could be catastrophic and even a small crack in a line could waste water for years to come. It seems to me that erring on the side of protecting your system is prudent.