Elk Relay for Fan Control

[SteveInNorCal]

Hi, All. New member here. I'm installing an Elk M1G system for security and lighting. Lighting control is via UPB and a little bit of legacy X10. I want to control my two attic gable-end fans. The fans are on in-line thermostats to cut them off when the attic temperature drops below a setpoint. I also want to have an override that shuts them off at a specific time (say 11:00 PM) on hot summer nights to keep the noise in the house down. I think the fans are rated at about 3 amps each (need to verify this). I'm considering two options:

1. A UPB fixture module that can be triggered by the Elk M1G at 11:00 PM
2. Use one of the the Elk Programmable Outputs (J16) to drive a relay.

Questions:

1. Are there other alternative approaches you would recommend?
2. Can I mount the UPB fixture module in the attic? I'm not sure what daytime peak attic temp is -- probably 130F? I'm sure it would be better to put it in the house conditioned environment, but interior space is at a premium.
3. If I choose to use a relay off a Programmable Output, would I use a Elk 924 DPDT relay or an Elk Heavy Duty Contactor/Relay? I know the 60A HD Contactor/Relay is way overkill for this application, but I like the idea of "real" screw terminals for the 14 gauge Romex wire. The relay terminals on the 924 relay meet my current requirements, but the terminal screws don't seem up to connecting 14 gauge Romex.

Thoughts? Thanks in advance.
Steve

 

[tmbrown97]

Hi Steve,

Honestly I'd use UPB and just keep it consistent. The inline relay should be fine up there - just make sure it's got a sufficient amperage rating. Some of them like SImply Automated's also let you hook a "remote" slave switch to it in case you want another control input somewhere - maybe even near the attic entrance or wherever it's easy to wire.

You could do the relay thing if you really want - if going that route I'd be tempted to get two low voltage DIN mount relays - that'd make for a clean install with the terminals like you like.

 

[SteveInNorCal]

Thanks, W2P. I was thinking about using an SA UPB Inline Relay Fixture Module, 12A - UFR-30 which is rated at 12A.

The wiring is about the same whether I use a low-voltage relay controlled by an output from the Elk or use a UPB switch as above. The wiring closet is right below the attic and it's straight vertical run about 4 ft. to enter the attic.

I also want to add a series switch (simple light switch, non-automated) before the attic relay, thermal switches, and two fire switches (to shut the fans down in case of fire). That way I can cut the fans off at a specific time via Elk relay or shut them down for the season with the override switch. I've already got the override switch wired into my closet.

Perhaps I should simply omit the manual override switch and replace it with the UPB fixture relay. With that approach, there would be no manual switch -- just the UPB automated switch followed by the fire switches and the thermostat switches on each fan.

 

[Del91574]

I'd recommend a RIB relay instead of any of the relays listed, separation and isolation of voltage and terminals, as well as the ability to mount to a standard trade box. The UPB can be used to control if really wanted, although not really needed.

 

[SteveInNorCal]

DELI -- thanks for the pointer to RIB. I was looking at their site and can't figure out which model to use. Do you have a specific model number?

W2P -- do you have recommended DIN mount relays? I was looking at reliable Potter Brumfield DIN with base. Do you have model number or manufacturer recommendations?

 

[SteveInNorCal]

DEL -- looking at RIB, I'm thinking a latching relay would be useful for this application. I would use one output to latch the relay on, another output to latch it off. A momentary 1 second energization should latch it on and off. I don't mind using up two outputs as the gable end fans are the only outputs I'll be using for the foreseeable future. That way I don't need to keep the relay energized the entire time the fan is on. Thoughts?

 

[gatchel]

If relays are plentiful then latching or not is up to you. I would wire it direct, if it were me. (one relay instead of two)

+1 for RIB (Functional Devices). They make a solid product.

J16 Outputs are rated at 50mA per output.

The RIBTE01B may work for you. It has a very low current (1-2mA at 12vdc) draw which would be good to keep the Elk consumption down. It would require 120V power and is rated for 1HP at 120V. It is also Optoisolated which is a good thing.

http://www.functiona...ts/RIBTE01B.pdf

There may be other lower cost options from the RIB line put they will draw more coil current from the M1.

 

[SteveInNorCal]

Thanks, Gatchel. That RIB relay RIBTE01B looks perfect with its continuous duty coil rated at 1 mA at 12 VDC. The latching relays require a momentary pulse to actuate, but the coil is rated at 350 mA, way too high for the Elk outputs. The relay is $25 at Apex Controls. I need a metal enclosure -- looks like a Bud JB-3957-KO 8" x 8" x 4" sheet metal enclosure with screw-on cover will work at $13.

I hadn't thought about using an opto-isolated relay to reduce the coil current to <50 mA. Great idea.

 

[tmbrown97]

You know, I'll withdraw the DIN recommendation - the RIB is a much better idea - not sure why I didn't think of it!

RIB U1C is the one I've used before.

 

[gatchel]

Either of the RIB's mentioned thus far will work for you.Just make sure you look at the specs on both models. The RIBU1C has less handling capability but still may work at half the price:

http://www.functionaldevices.com/pdf/datasheets/RIBU1C.pdf

 

[SteveInNorCal]

You know, I'll withdraw the DIN recommendation - the RIB is a much better idea - not sure why I didn't think of it!

RIB U1C is the one I've used before.

Thanks W2P. I just ordered the RIB U1C from Apex Controls, $14. It has a a 15 mA continuous duty coil at 12 VDC without the opto-electric isolation. Should work fine.

I'll bring the 12 VDC through one of the top black bushings. For 110 VAC power, I'll attach the built-in 1/2 nipple to a junction box. What type of j-box do you use for this? This approach avoids the Bud enclosure.

 

[Del91574]

Depending on conduit size of the fitting on the RIB and how many wires you've got, you really can't go wrong with either a 4" or 4 11/16" square box, plenty of room and cheap to find anywhere.

 

[tmbrown97]

Depending on the layout, I'd do something along those lines (what DEL said)... whatever mounts easily and gives you the room you need; if connecting to conduit it's easy enough - if straight romex, use the proper clamps to keep it from pulling out.