N30 controller

[bodhisatva]

I've got a church/school building with Metasys that's having problems maintaining setpoint. Can turn the baseboard (hydro) on manually from the PC but then it just runs continuous and overheats. Customer wants to upgrade software to something more user-friendly anyway(?). The VMAs contol the zone valves for each zone with info from wall mounted sensors but my feeling is the problem is in the N30. Or in the way they're trying to use it. Someone know of similar trouble? What's the web address for their tech bulletin board? The church is ready to scrap the whole system if I can't get answers for them. Please help!

[davem]

First, just what software are they using to access the system? M3 and M5 are both quite user friendly, provided the installer has taken his time to set up the information in a user friendly format. If there is no workstation software (and with an N30, there doesn't need to be), but rather simply a terminal mode with text menus, that too need not be overly complicated for a customer to learn to use.
The temperature control issues are most likely not the fault of the N30. The N30 doesn't have the internal programming available to handle much temperature control, so the problem is most certainly within the VMA's.
With reheat situations, we've found that putting absolute trust in the VMA's PRAC algorithms is not always wise. We found that the PRAC had the heating control loop so wound up that it took a reheat valve over 8 hours to move full stroke. By disabling the PRAC, and manually entering realistic PID settings, our temperature control loop issues were fixed immediately. Worth a try.

[bodhisatva]

Thanks for the reply Dave. I think they just have the terminal mode with test menus, no graphics or anything in the way of onscreen prompts or help menus. You're going to have to bear with me on the terminology here. What's the PRAC and how do I find instructions on how to disable it and manually enter the PID (what?) settings? I'm not a full-fledged controls guy yet, but I'm doing the best I can for these folks. They had an outdoor air temp sensor that went bad earlier and I was able to fool the control with a 1K resistor into thinking the outdoor air was below set point till I could get a replacement. I have a feeling I'm going to need to reprogram the VMAs. Can I do that with HVACPro? What version is best? Is there another software program for troubleshooting these systems? Thanks again for your help!

[chrisc]

Is System Tools loaded on the PC? If so, you'll be able to gain access to the VMA through HVAC Pro in pass through mode. First you need to find someone who knows alot about HVAC Pro and VMAs. Can the church locate the controls contractor who did the install or is it all in your hands? See if you have the software on the PC, if not you'll have to acquire it, through JCI. They'll get you for quite a few bucks to purchase it. You'll be looking for Configuration Tools Rel 8.06, unless they've come out with a new Rev. Good Luck, I'll help out if I can, my company is a JCI ABCS.

[lwarren]

Good luck with the N30, they don't even make that hunk of junk anymore. I heard Johnson canned the entire design team behind the N30

[control_noob]

Originally posted by lwarren
Good luck with the N30, they don't even make that hunk of junk anymore. I heard Johnson canned the entire design team behind the N30

That's odd, plenty of N30's available here, now and well into the future. I've been told by JC that the N30 will see support way into the future and it is far from the legacy dungeon.

[lwarren]

Originally posted by control_noob

Originally posted by lwarren
Good luck with the N30, they don't even make that hunk of junk anymore. I heard Johnson canned the entire design team behind the N30

That's odd, plenty of N30's available here, now and well into the future. I've been told by JC that the N30 will see support way into the future and it is far from the legacy dungeon.

Thats just what I was told, I can't verify it though!