My main issues on outdoor pickup locations/devices is ice, spiders and wind.
If the pickup is well placed for avoiding ice and wind seems like the spiders think it can be a good place to live and start a family.
Chuckle, true enough.
Originally Posted by sysint
But do you know of any solutions besides checking time to time?
Its about like a conversation I had with an in-house maintenance guy. He had several VAV's with air flow sensors not working right. Well, actually, he didn't know what the real problem was. Just knew they weren't working right.
I disconnected tubing to pickup tubes and blew 25 psi air through em, gotten from nearby control line. In most cases, fixed his broken, except one when tubing itself was cracked and another where pitot inside duct was broken.
Told him, "Yeah, they never mention this sort of things to guys, but a good idea to blow out or otherwise clean out such things. Over time little holes get clogged with dirt/dust, bugs, pieces of insulation, or whatever."
Osiyo - great points and I do set them to the lowest setting 0.1" wc, but most 'specs' I've come across seem to favor 0.5. I like the bi- directional setting for trending purposes. I agree once your below 0.0" wc it doesn't matter much if your sensor is sensing correctly. Sometimes the sensor is off just a bit or being affected adversely so I like to test slightly positive and slightly negative according to the sensor aka some simple cracked door and paper tests just to see if air is going in or out then. Another thing I've recently found it useful for is alarming. > -0.025 at one building the gals have a hard time opening doors. So alarm at < -0.02" wc if > 5 minutes. Long story but building under construction yet and too many holes and during certain construction activities we can't bring in any outside air. Let's just say my trends were extremely useful in proving out a design flaw and a construction exhaust problem.
On another job, my first real 'learner' on wind effects we were able to find the correlation between consistent wind speeds above a certain value and the building going negative. That's the building I found the center of the flat roof to be the ideal sensing location. Ever since if I can get my outdoor reference to such a location I will.