Near Intersection of I-35 & I-90 Southern Mn. | For your setup the 440 must be set for Control - Fast Close. From your observations, I suspect that your 440 is operating in Standard Control.
If it is set to Standard then the control valve will not close down when the sections are shutoff. Standard control is used with the Accuflow setup with a separate standard control valve and a Main or Master ON/OFF valve. Standard control is also used in many sprayer setups.
Depending on the age of your 440, there are differences. 1) if your 440 is really old - it may not have the Fast Close option. 2) If your 440 is fairly new, the initial settings will be abbreviated 3) If your 440 is quite new with a single wide display area rather than two smaller sections then the settings are spelled out more clearly.
To check the current settings push the Self-Test key and you should see the initial settings of your 440. These settings will scroll by. One setting is US (for United States measurements of acres, feet etc.) Another setting is SP1 or more likely SP2. SP1 is correct for wheel sensors and SP2 is correct for radar or simulated radar from a GPS. The control choice is another setting. It might be Standard, Fast Close, Fast or possibly some other choices depending on the age of the 440.
You will want this setting as Fast Close. This means that the system should just give the control valve very short bumps while in operation (a fast valve - not geared down) but close with the section valves. If yours is currently set to Standard then the Control Valve will not cycle OFF when the sections valves are shut off. The control valve will stay at its current position. This would mean that NH3 could still pass through the control valve and go through the heat exchanger and eventually flow out the vapor tubes. This would not be acceptable because you would have no way of completely shutting off the flow. Also if the control is set in standard, the system would give much larger bumps to the control valve which would result in poor flow control.
If this setting is incorrect it needs to be changed. This process is somewhat different again depending of the age of the 440. Essentially you want to get back to the point where you are able to change the various multiple choice initial questions.
You ask if the section valves are really doing anything when the Master is shutoff. Yes and No, the section valves will close but no product should be getting to them when the Fast Close valve is closed. If they were left open, the system would drain down more completely on a headland so having the valves close tends to keep product in the line between the Fast Close valve and the section valves. This means you get more immediate response when the system is turned on again.
Edited by tedbear 3/9/2013 09:17
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Raven Accuflow ?
