# Cabinet heater / vent



## John Valdes (May 17, 2007)

Check with Hoffman or Schaefer and see what they offer.

Being they are outside with no people around to look after them I would not use air conditioning. AC quits, cooling quits.
I would vent in the bottom and out the side, near the top. They do make vents for this type of application.


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## Mouser (May 4, 2011)

If it's mounted to a wall, maybe a small roof to shade it from the direct rays of the sun.


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## AK_sparky (Aug 13, 2013)

Hammond has a couple of rainproof vents. I haven't used them; YMMV.

https://www.hammfg.com/electrical/products/climate#ventilation


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## glen1971 (Oct 10, 2012)

Do you have any air lines near them? I've installed a venturi type cooler in PLC's in compressor buildings that drastically reduce the temp inside the cabinet...


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## splatz (May 23, 2015)

I saw those little whirligig coolers, very interesting, but no compressed air. 

It's on a concrete pad in the middle of nowhere, so if I want shade I'll either have to build a roof or plant some trees  

Hoffman and Schaefer both had vents and fans, but nothing really insect resistant. The Hammond products at least claim insect resistant, I'll look at those more closely. 

Automation Direct has these

http://www.automationdirect.com/adc..._Thermal_Management/Enclosure_Heat_Exchangers

which looks like air conditioning without the compressor, may be overkill but I'll look at them more closely. 

Thanks for the suggestions!


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## LarryB (Jul 20, 2010)

We've got one of these on a shrink wrapper control panel.
Might do the trick for ya.

http://www.iceqube.com/heat-exchangers/


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## bill39 (Sep 4, 2009)

I'll second what Mouser said about sunshields. They make a huge difference.

The project we are working on now is requiring sunshields on the South and West side of outdoor panels.

Here's a link to Hoffman's thermal calculator. It's easy to use and since it's online there no need to install any software.

http://thermaltool.hoffmanonline.com/sizing_application.html

On one particular installation in the past I glued 1" blue styrofoam to the sides, bottom, and top of the panel to keep it warm enough in the winter. However, we then also had to add an A/C to keep it cool enough in the summer.


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## splatz (May 23, 2015)

Turns out Hoffman has something that may work after all: 

http://www.pentairprotect.com/en/ho...r-Fans/Outdoor-Filter-Fan-and-Exhaust-Package 

I am going to try this first and see if it does the job.


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## JRaef (Mar 23, 2009)

Quick and dirty rule of thumb on heat exchangers:

You need a MINIMUM of a 10deg C delta in temperature for them to work. So if you want to keep the insides at 40C (104F), the OUTSIDE air temperature must be no MORE than 30C (86F). If your outside air can get to 99F, a heat exchanger isn't going to keep it cool enough inside.

As to the Hoffman filter:


> Removable F5 filter


An F5 filter is essentially like a hand held vacuum cleaner filter. The problem with that is, it's going to load up and need to be changed, probably at least once per month.

If it were me, I would just go with a fan exhausting out of the top, intake on the bottom, with an _aluminum _window screen over the intake hole. You can't keep out ALL insects, but you can make it difficult and inhospitable for them. The only reason ants would work hard at getting through a screen to go in there is if they smell food or water. Put in a space heater to keep it free of condensation (you need that no matter what) and don't store your lunch in it. Use a Hoffman Corrosion Inhibitor emitter inside too. They last about a year, and put out a tiny amount of a gas that keeps moisture from causing oxidation. That's also a mild poison, so if the ants try to nest in the rain because it's dry, they eventually die.


And yes to the styrofoam insulation if you have room, makes a difference in the winter when you have to have the vents for the summer.


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## telsa (May 22, 2015)

The cheesy cooling fans sold with PCs will be more than enough.

You could even power them with a small PV array, as night time temperatures don't figure to break 100 degrees.

You can re-purpose heat sinks from old power supplies -- or just order new ones.

Bolt them onto the outside, use the heat transfer paste, too.

A doubled containment -- a can within a can -- would keep the critters out of the vitals -- while the fan and heat sinks kept the temperatures reasonable.

It wouldn't hurt if the exterior can had a layer of insulation -- on its outside -- to keep direct solar radiation off of the box.

Mix and match any of the above, to suit.


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## Cow (Jan 16, 2008)

I didn't read all the replies but one of my customers has vfd's in large enclosures that he said would always trip out on overtemp in the summer heat. He said painting the gray electrical enclosures white made enough of a difference they quit tripping on overtemp.

I've never tried it myself.


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## splatz (May 23, 2015)

Cow said:


> I didn't read all the replies but one of my customers has vfd's in large enclosures that he said would always trip out on overtemp in the summer heat. He said painting the gray electrical enclosures white made enough of a difference they quit tripping on overtemp.
> 
> I've never tried it myself.


I can believe it, but in this case it won't help, they are shiny stainless steel.


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## splatz (May 23, 2015)

More good ideas, thanks all for the input. 

The site is unmanned, but they do visit it at least once a month to do general site maintenance. I think I'll try the filters and see if they can make it from maintenance visit to visit without clogging up, and plan to try a less restrictive filter if they do. 

It's wild kingdom at this site, the insects get into everything. Ants found their way into this cabinet by coming up the conduit that goes to an underground vault.

I'd like to try some of the more elaborate ideas, but at this site, there is near zero tolerance for downtime so I try to keep things as simple as possible for the sake of reliability.


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## splatz (May 23, 2015)

I'm going to have to make pretty big holes in this cabinet ... I will probably use this gadget 










Slow, but doesn't make many mistakes. Never used it in stainless though...


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## bill39 (Sep 4, 2009)

splatz said:


> I'm going to have to make pretty big holes in this cabinet ... I will probably use this gadget
> 
> 
> 
> ...



What is this? Is it for cutting the notch on pushbuttons?


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## John Valdes (May 17, 2007)

glen1971 said:


> Do you have any air lines near them? I've installed a venturi type cooler in PLC's in compressor buildings that drastically reduce the temp inside the cabinet...


Be careful with these things. I have seen panels dripping wet inside because of them.
They do work though. But you need compressed air.


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## stuiec (Sep 25, 2010)

Dunno if anyone has already suggested this for the ants, but they don't like crossing a line of diatomaceous earth.


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## splatz (May 23, 2015)

bill39 said:


> What is this? Is it for cutting the notch on pushbuttons?


It's Klein's sheet metal nibbler

http://www.kleintools.com/catalog/cutting-notching-tools/nibbler-tool

it punches a bite about maybe 3/16" every time you squeeze the handle, without distorting the metal at all. You can drill a 1/4" hole to start it in the middle of a sheet. It will be sloooooow but much less of a chit show than faster methods for a square hole.


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## splatz (May 23, 2015)

I figured I would put a thermostat on the fans, they make this one










The rep at Hoffman thought that was dumb, just let it blow at all times, I can't see how that would be a good idea outdoors.


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## dmxtothemax (Jun 15, 2010)

I think that cooling fans with a thermostat
Will work best 
But they will need regular maintenance
If they are to work best.


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## JRaef (Mar 23, 2009)

splatz said:


> I can believe it, but in this case it won't help, they are shiny stainless steel.


I did a ship-to-ship cargo transfer control system for the Navy once, all in very beautiful 316 brushed SS enclosures. After I delivered them, they installed them and painted them gray...


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## JRaef (Mar 23, 2009)

John Valdes said:


> Be careful with these things. I have seen panels dripping wet inside because of them.
> They do work though. But you need compressed air.


And lots of it.

I used them on crane control panels over the pot lines in an aluminum smelter once. They worked great and survived where nothing else would. But the smallest ones I could buy from Vortex took an amount of air pressure and volume that, when converted to compressor loading, came out to be about 7-1/2HP continuously! That's a LOT of energy if you have to pay the bill to run the compressor...

If anyone wants to try those, make sure you use a VERY good dryer and oil separator. Most of the time you end up having to use what's called "instrument quality" compressed air.


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## Bird dog (Oct 27, 2015)

JRaef said:


> And lots of it.
> 
> 
> If anyone wants to try those, make sure you use a VERY good dryer and oil separator. Most of the time you end up having to use what's called "instrument quality" compressed air.


FWIW in the early 90s a mechanical guy told me to get rid of 90% of my problems with air valves the control air line needed a heater and a filter that would filter out particles down to 3-5microns. It's virtually clean air.


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## emtnut (Mar 1, 2015)

splatz said:


> I figured I would put a thermostat on the fans, they make this one
> 
> 
> 
> ...


I've used these exact same units, but they say Stego on them. 
They're great, they come in heating/cooling or both, and the price is right too !


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