What Control strategy uses.....

[blabath]

What control strategy uses 24vac and has three wires; one common, 0-24vac on one line to drive cw and 24-0 vac to drive ccw? This is in a Lennox VVHC system and I'm trying to replace the damper actuators. It seems like Belimo LMB24-3 ought to work, but it doesn't because it's not really floating point control. sometimes there's 24 vac on one input line, sometimes it's on the other and sometimes there's 12 vac on each.
Thanks for the help.

[joey791]

Pulled the manual on this because I'm not familiar with the system(haven't seen a VVHC). The Lennox says the actuators are ML6161 which are Honeywell and the same as the LMB24-3 or LMB24-3T

[Igotworms]

It sounds like its an incremental actuator (output x drives actuator one way, output y drives actuator the other way). Any actuator should work as long as it accepts the same signal.

[blabath]

You'd think so, but it doesnt work. The thermostat splits its 24vac between the two inputs. Almost never does it have the entire 24vac on one line, then the other, THAT would be too easy. The LMB24-3 needs the entire 24 on the y input or the w input.

[ncboston]

This is the actuator that Joey was referencing.
http://www.industrialcontrolsonline....=1305&survey=y

[Control Man]

If you do have the HW ML 6161 its a TRISTATE a nd can be replaced with the KMC MEP-5073 ( obsolete but still around ) or the KMC MEP-4001 also SIEMENS GDE131

[blabath]

Thanks for the help guys. I think I'm headed in the right direction now.

[joey791]

According to this, an LMB24-3 should work, unless I misread

http://www.zonexsystems.com/PDF/ARCH...C%20Manual.pdf

[lowdrive]

Are you sure the signal is not a 0-135 ohm Honeywell wiper signal? Belimo offers that as an option. The sweep is the 0 - 135 ohm resistance from end to end. The wiper (like a windshield wiper) floats in between the two ends, giving (for example) a signal of 100 ohms from the wiper to one end of the sweep and 35 ohms from the wiper to the other end of the sweep.The "wiper" in between the 0 and 135 ohm "ends" will create a different proportional piece of the signal out of each end of the "sweep".

[blabath]

Here's the original actuator. Still having a time trying to match it. I bought a couple of ML6161B's on e-bay to try.

[Control Man]

Take a look on the 2nd page of this PDF , it looks what you have http://www.zonexsystems.com/PDF/INST...AHDM_instr.pdf

[joey791]

Take a look on the 2nd page of this PDF , it looks what you have http://www.zonexsystems.com/PDF/INST...AHDM_instr.pdf

Nice
find

[controldude]

If your just having problems controlling the actuator make sure your 24vac is tied to the common terminal I've seen this throw plenty of people. If it's finding one that fits the application I would follow the previous suggestions.

[blabath]

Wow It looks like zonex didn't do anything other than put a sticker on a LMB24-3T. I've already tried that and it doesn't work. Maybe I have a goofy thermostat. And, yes I've already checked the Mc/Ro and RC terminals to make sure the wires are hooked up correctly.

[blabath]

The Honeywell ML6161's did the trick. Also, they are plentiful on e-bay and such, new, in the box even though they're obsolete.