Interesting dilemma...I agree with you. I do not have an engineering degree - I'm an MIS guy with a lot of control experience - so I call myself a controls specialist as I do not want any preconceived notions - at least not for me. I do the same thing for my guys - I call it like it is (ie...
I need your in/lbs for the actuator and I can help you. You may or may not like my solutions but I have a few as we ran into this problem this year with a highly corrosive application (water treatment plant beside the ocean).
I also took pictures of what we did so I can send them to you.
Okay,
So here's the deal.
Generally you are trying to maintain say 55 deg. F (adjustable) in the mixed air chamber (not supply) when you are in the economizer mode. Remember - mixed air - will become the supply air.
So if we look a standard economizer cycle, if the unit is calling for...
It's quite straight forward.
Need the voltage range and the pressure range. Here's an example:
Assume you are using the standard voltage output of 0 - 5 VDC.
And let's say the range is 0 - 2.5 in. wc.
If you are reading 2 volts on your meter then you would convert as follows:
(2 volts x 2.5...
Like Willard3 said, you haven't given us enough information. But are you asking if should it take one minute? Two minutes? 10 minutes?
It all depends on the controller and how it's set up in the PID loop. PID stands for Proportional Integral and Derivative. Usually we only wet up the...
When did this start to occur? I would agree with IRstuff and a flow issue. Have you upgraded the filters by any chance? If so, that might be creating a problem. Berkshire and imok2 have the right idea in their analysis.
Chilled water.
Think of the maintenance of the DX system in those conditions - it would end up being full time. Also, no flexibility.
How much is a rig worth? $ 500 million? 1 billion? What's the chilled water system worth relative to that and the daily production costs?
Okay,
A couple of things to check for.
1. Depending on the type of flow switch, try taking the cover off and see if it makes with the pump running.
2. If not, then take it out and see if the paddle has the ability to stroke freely.
3. See if the paddle can run a fully stroke in the pipe...
One other thing I forgot to mention. While 1.5" is the norm for duct static design, we do work with many lower static pressures.
Let me explain. Generally as the designer, you design everything around 1.5" - generally. What we do however is once everything is ready is we open all of the VAV...
The reason I said .1 at the box was because I thought you wanted to know the minimum to get a good reading. And again I'm trying to remember from another job from two years ago how we did it. Why I say this is because we couldn't get a decent CFM reading out of the boxes and couldn't figure out...
No chewing or spitting? Good. And since you knew them,even better. So make sure when you recommend that they know about it tell them not to let you down. And to minimize the change orders.
I'm not trying to bust you kahone's but if you haven't done this before then you really shouldn't be doing it. The contractor will eat you up and spit you out if you've missed something.
Ask one of your colleagues that goes this and maybe ask a mechanical contractor that you've worked with who...
