Economiser 2-10 vdc signal

[ltd]

I have a building that is under construction. The engineer has designed a smoke evacuation strategy that requires Carrier economisers to drive full open. I contacted Carrier tech support and they in turn called their engineer who came up with a schematic. This schematic requires closing of a relay that sends 24vac to the 2-10 vdc control input on the damper motor while opening the 2-10 vdc signal. Has anyone seen this done? Will it work without burning up the actuator?

[CE-TECH]

I've never heard of sending 24 vac to a vdc motor and it actually driving. Maybe I'm wrong but I'd make sure to have a replacement actuator with you when you try it. Carrier should cover it when it burns up

[ltd]

I've never heard of sending 24 vac to a vdc motor and it actually driving. Maybe I'm wrong but I'd make sure to have a replacement actuator with you when you try it. Carrier should cover it when it burns up

That was my initial thought. Have a bunch of spares on hand. But seriously, the actuator is 24vac but normally is driven by a 2-10 vdc signal from the honeywell module based on minimum position, free cooling, co2, etc.

[amickracing]

If'n it were me (and it's not), I'd probably throw a 24v relay up there and use that, then wire your economizer through the relay.

I just replaced one of these actuators (if it's the style I'm thinking), looks almost identical to a mod motor for a boiler. The one I put in was 24vac, but it was also driven by 24vac.

I'm no 'tronic expert, but I've always thought putting DC to an AC device leads to a whole lot of nothing happening. Put AC to a DC device and it might work once, right before it lets the smoke out.

[ascj]

I have a building that is under construction. The engineer has designed a smoke evacuation strategy that requires Carrier economisers to drive full open. I contacted Carrier tech support and they in turn called their engineer who came up with a schematic. This schematic requires closing of a relay that sends 24vac to the 2-10 vdc control input on the damper motor while opening the 2-10 vdc signal. Has anyone seen this done? Will it work without burning up the actuator?

Hopefully your are understanding the schematic wrong. 24vac to a 10vdc actuator is a quick burn out.

You don't happen to have a model number of the economizer?

[ltd]

Thhis is a Carrier Economiser IV, which I looked up on the Honeywell website as a W7212A1017.

[can2man]

That won't work. You can't use an ac signal - the control won't respond. Call again. That is my understanding - let me know if I AM wrong.

[ltd]

I don't know what kind of electronics are inside this actuator. That's why I am asking the question of whether or not it will drive fully open with a 24vac signal. I wonder if the actuator sees this voltage as a max, sort of like a 10vdc signal. Initially, I thought the engineer was not seeing the same actuator, but then I thought differently.

[BKS60]

Just curious
Is there a constant 10vdc signal availible?
If so installing a 24vac relay with 10vdc to N/O would be a quick and simple solution.

[ltd]

There is a 2-10 vdc signal available from an AO on the building energy management controls board. That is one option I had considered in conjuncton with a relay, like you said. I thought that would be the easiest option. Until I got the drawing from the engineer, which although it is simple, may not work. So I am asking my fellow professionals for their opinions. Thanks.

[BKS60]

You may want to check with the BAS contractor to be sure your dc signal will be availible if the building goes intomoke alarm. And of course your 24ac would need to be pulled from a source that would also not be shut down.
Obvious I know but needed to be said.

[ltd]

Yeah, those engineers walk on water. Of course, the voltage supplies are all from emergency power, right? If not, more engineers screwed up. I have three methods I came up with to power this damper open during smoke purge. None of them matched the engineers, so I thought he or she might be right and I just didn't understand the inner workings of an HF23BJ054a Carrier actuator made in Germany.

[Dallas Duster]

That won't work. You can't use an ac signal - the control won't respond. Call again. That is my understanding - let me know if I AM wrong.

I just want to say that you are wrong. Should work I believe it is a belimo motor if I'm not mistaken. What the model number of the rtu?

[yellowirenut]

if the smokies trip that should shut down the supply fans right? then why open the damper? Maybe its just my area but the inspector and fire marshal wants the units dead if they detect smoke....no fans no nothing.

[Dallas Duster]

if the smokies trip that should shut down the supply fans right? then why open the damper? Maybe its just my area but the inspector and fire marshal wants the units dead if they detect smoke....no fans no nothing.

Smoke evacuation. Supply fans turn off dampers go to 100% and powered exhaust put the building into a negative.

[yellowirenut]

that makes seance to me...but would it pass code? "the doors not locked but i cant open it..grrrr to much pressure." *drinking, forgive my rambelings

[Dallas Duster]

that makes seance to me...but would it pass code? "the doors not locked but i cant open it..grrrr to much pressure." *drinking, forgive my rambelings

Good point maybe it`s for warehouse or some kind of storage space and not for office space. No fuel no fire right ?

[CE-TECH]

What model # unit is it? I know some units have a "smoke evacuation" mode.

[ltd]

Actually this application is for a county jail. None of the inmates will be leaving. If smoke is detected, return air dampers close, outdoor air damper drives wide open, supply fan runs, smoke exhaust fan energizes, pulling smoke out. The actuator may be a Belimo, it has a Carrier OEM number on it, HF23BJ054A. RTU model number is 48HJE009-551HQ.

[GUDTEK]

I have a building that is under construction. The engineer has designed a smoke evacuation strategy that requires Carrier economisers to drive full open. I contacted Carrier tech support and they in turn called their engineer who came up with a schematic. This schematic requires closing of a relay that sends 24vac to the 2-10 vdc control input on the damper motor while opening the 2-10 vdc signal. Has anyone seen this done? Will it work without burning up the actuator?

Don't most logic modules have terminals for remote minimum position...? Terminals P and P1 when jumpered will drive full open. Use your relay to jump these two when purge is needed. Won't smoke any motors, but will rely on onboard econ power.