I had done a good amount of work on the cooling system at our transmitter site in Gillette–Last time I was there I noticed a relay that had failed.  I finally had the opportunity to get back to the site and install the replacement.

While I probably could have made it up to the site in the truck, the Polaris did a fine job getting up the muddy and snowy hill with tracks.

 

 

The road has some drifting–just enough to make me take the Polaris instead of the truck up the hill.

Slightly warmer in the shack than I like to see it…It should be close to 70 degrees.

The offending cooling unit

This is the “economizer” section–it should open to let cool air in but is not doing so consistently.  I have already replaced the economizer motor and temp sensor…

What a mess of wiring!  At least it is a fairly simple design…no microprocessors here!  Lots of relays. 

This is the “mixed air relay”.  It controls the action of the economizer to mix outside air into the system.  When it malfunctions the system will not bring in any fresh air from outside.

The replacement relay–pretty easy to install.

New relay installed.

The old relay–removed from service.

The economizer is now operating properly.  Here it opens slightly to let in cool air.

A terminal lug has come loose…a simple repair.

Set to 70 degrees…

Much better–this thermometer is next to the door so it is actually reading slightly low.

Done!