A better blowout...

We always use a fairly large compressor to purge water from the 20+ miles of pipe on the golf course each fall, but the past two years the rental company sent us one which is the size of a small bus--a massive 1,600 CFM compressor.  Using this to blow out the entrance island pop-up sprinklers definitely seems a bit excessive.

Even with this huge machine, the blowout went very smoothly this year, thanks in part to an off-season purchase of a 2" pressure regulating valve (shown below).  In the past, our efforts to regulate the pressure manually, by opening and closing valves, was at best, hit or miss.  We would often have pressure spikes which can put unnecessary stress on the system's pipe and fittings, and typically resulted in launching a few sprinklers into low Earth orbit.

The regulating valve is installed in-line between the compressor's discharge hose and the pump station.  While it might not look all that impressive, this valve is a fairly expensive piece of hardware.  However, from what we saw this week, it was well worth the investment.

One other concern when moving this much air is heat buildup.  There have been many times when the compressor discharge hose actually got hot enough to burn the turf it was resting on--and temperatures like that aren't going to help the 30 year old piping we have in the ground.  A few years ago, we came up with a simple way to dissipate the heat and lower the temperature of the air.  

We install one length of 2" discharge hose going from the compressor to the irrigation pond, then have the air travel through a 20' section of 2" iron pipe which is in the cool water, before heading back to the pressure regulating valve, and the tie-in at the pump station.  As water transfers heat much more efficiently than air (think how bone-chillingly cold jumping into a 60 degree pool feels compared to walking outside when the temperature is a pleasant 60 degrees) this quick time in the pond has made a significant difference in the temperature of the air entering the irrigation system.

While the date may vary somewhat from year to year, blowing out the irrigation system is definitely an indication that the season is nearing its end.  We now have a chance to catch our breath as we start preparations for the upcoming golf season.  Certainly, after all of the challenges of 2020, a quick breather is appreciated.