To relay or not to relay? That is the question!

KlevrPhelo · 03-29-2003, 02:46 AM

First off.. I'm pleased to announce that my very first water cooled rig is well under way... WOOT WOOT! After almost a year of planning and modding the case, it's finally coming down to the wire. I would like to say many Thanks to any and all who've responded to my posts that helped me along the way!

Now... on to my question:
I'm debating on whether or not I should put a pump relay switch on my machine. I like the idea of being able to turn off the pump with when turning of the machine... but on the other hand, I would like to have the option of turning on the pump without booting up the computer.

Any suggestions?

Althornin · 03-29-2003, 02:57 AM

pick up a cheap relay from Radio Shack (cost, about 3 bucks) and wire a switch in parralell with it. leave the switch off for normal (computer on --> pump on, computer off -->pump off) operation, and turn it on for straight "pump on" operation. cost to you: about 5 bucks and 15 mins of wiring.

max · 03-29-2003, 06:03 AM

I used a solid state relay which was quite cool, no sound etc

CheeseBall · 03-30-2003, 10:34 PM

I am wanting to wire up one of these also. What is the model number of the relay you used max? And where can I get it. I heard maybe allelectronics.com and bgm.bgmmicro.com, or will radioshack carry it. Also, if someone could post a model # for a good switch that would be great also.

Thanks a load,
Bryan

max · 03-30-2003, 10:46 PM

I cant remember the model of mine and i got it in new zealand - where i live. They are not uncommon and have heaps of different brands/models to choose from (just like normal relays), just make sure it has the right voltages eg mine: 100-300 VAC and 3-30 VDC to switch it

Althornin · 03-30-2003, 11:55 PM

The radioshack relay you would want would be this one:
RadioShack Relay 275-218
Then any 120VAC switch (that handles enough current). Apparently relay price has gone up since i purchased. But any 12V switched relay will work fine, in parallel with a switch, to do exactly what you want.
Example switch: RadioShack Switch 275-666

Note that this switch can handle 3 amps at 120VAC, and the relay is good for 10 amps at 120VAC. Both are extreme overkill (power handling wise) for this project (running a pump that uses what, 20 watts = .2 amps at 120VAC) but thats not nessesarily a bad thing. If you can find a cheaper relay/switch that more closely meets your power requirements, then go for it.

hara · 03-31-2003, 07:16 AM

Using a relay is the way to go. I even wired a switch to the circuit so that one can turn on the pump while the pc is off. Good for filling.

TerraMex · 03-31-2003, 09:39 AM

Relay. I have one , and did the same thing that Hara did, i have two switches:

- Switch 1 , in the 12v side of the relay. When on, the PC is on, the pump is on. Off, the pump stops, even with the PC on.

- Switch two, in the 220v side . When on , the relay depends on the above switch (1). When off, the pump is kept working independent of the state of the relay, so its a bypass.

Works great.

airspirit · 03-31-2003, 06:11 PM

Check this out:

http://www.criticool.com/Powerplant.htm

It fits in a PCI slot, pulls power from the PSU (molex connector), and relays to the pump. Installation should take about five minutes. Strip your wires, screw them in, fire the computer up, and you're running. It is more expensive than the radio shack method, but having done that myself, I don't know that I'd want to deal with that again.

This is more idiot proof, and looks a hell of a lot nicer in your system.

UnloadeD · 03-31-2003, 06:34 PM

I didn't use a relay. I tapped into the AC of my psu's switch. Connected it to the pump with a molex, while I was in the psu a cut the green wire going to the motherboard and ran it thru the two blank spaces left on the molex. All of this serves a few purposes I was after: 1) one power cord out the back of my puter 2) if psu is ON pump is ON 3) if pump isn't plugged into psu, the puter won't start. All my needs were met and it was easy and really cheap, because I already had the needed parts on hand. I can turn on the pump without turning on the computer, I can't turn on the computer without the pump. Here's a simple pic:

edit: another pic

peace.
unloaded

Althornin · 03-31-2003, 10:25 PM

Quote:

Originally posted by airspirit
Check this out:

http://www.criticool.com/Powerplant.htm

It fits in a PCI slot, pulls power from the PSU (molex connector), and relays to the pump. Installation should take about five minutes. Strip your wires, screw them in, fire the computer up, and you're running. It is more expensive than the radio shack method, but having done that myself, I don't know that I'd want to deal with that again.

This is more idiot proof, and looks a hell of a lot nicer in your system.

If you want the RS method to look nice, just put it in an empty film canister. Thats what i did. It looks very nice, and clean.

CheeseBall · 04-01-2003, 01:43 PM

Unloaded I like the way it works, but I dunno if I wanna try it. Can you post more details of how exactly you did it? I have done some automotive and home electrical wiring but the thing is I dunno if I wanna open up my PS.

Oh yeah, and is there a good way that isn't too complicated to power the pump w/ your PS while using a switch and relay. And not opening up the PS? I don't wanna get to advanced so I'm guessing probably not.

airspirit · 04-01-2003, 04:26 PM

The bare leads for 120VAC and 12VDC (req. for the pump and relay) are inside your PSU. You cannot access the 120VAC from outside of the psu unless you have a passthrough plug and you don't mind chopping a power cable. The bare 120VAC leads are normally positioned in your PSU in a way that limits the risk of damage to any other components ... unless you're afraid of voiding your warranty, you should at least make your decision after popping it open and looking at what it would take to wire in your pump wires.

UnloadeD · 04-01-2003, 06:48 PM

Quote:

Originally posted by CheeseBall
Unloaded I like the way it works, but I dunno if I wanna try it. Can you post more details of how exactly you did it? I have done some automotive and home electrical wiring but the thing is I dunno if I wanna open up my PS.

Oh yeah, and is there a good way that isn't too complicated to power the pump w/ your PS while using a switch and relay. And not opening up the PS? I don't wanna get to advanced so I'm guessing probably not.

Hey, I'm not trying to knock you, but if the pictures don't make sense to you, you prolly shouldn't be trying this yourself. The line voltage can be dangerous to you, your puter and even your house. Its a very simple mod if you have basic electrical skills. If you know somebody who is familiar with electricity show them the pics, and then have them do it for you and explain as they go. Having said that, there are some relay kits you can buy and use without opening your psu. But like airspirit said, you will still have to splice your pumps wires and use a pass thru. This will leave you with 2 power cords coming out of the back, also it would be possible to run (fry) your puter witht he pump unplugged. And lastly, you are still dealing with line voltage, so the danger factor is still there. No matter which route you go, get some help. There's no shame in it, we were all taught this stuff by somebody. Learning about fan and led voltages is fine for message boards, but you really need somebody there with you once you start on higher AC voltages.

peace.
unloaded

airspirit · 04-02-2003, 01:03 PM

With a good relay, you shouldn't burn your PSU if the pump is unplugged, as there wouldn't be any 120VAC passthrough ... but without knowing the exact setup of your relay, that is a concern. As far as the premade kits, you can always purchase a three prong female 120VAC plug and wire that directly into the three screw connectors on that kit I referred to above. That costs about $1.50 for the plug. Then you can just plug the pump into the card without cutting your pump's cables ... I did something similar by modding a power strip when I installed a dimmer for my 120VAC fans ... I modified the cable going to the power strip and put the dimmer inline there, leaving me with a dimmed power supply that I could just plug my fans into. There was no way in hell I was going to modify such expensive fans. All I have to do is plug in the power strip (the dimmer circuit is mounted externally and the strip is internal), plug the fans into that, and I have speed-regulated AC fans.

CheeseBall · 04-03-2003, 02:28 PM

I understand your drawing (I think), I just need to know how to find out which lines to wire into on the PS switch. From your picture I can tell the lower one is live but will mine be the same? The male plugs are already on the switch correct, or did you have to mod them? If they aren't there I might not try this.

Also, if you shut down your computer, but the switch on the PS is still on. The pump will still be running correct? So I would be able to fill/bleed everything, right? Then once I am done bleeding, just hit the power button on the front of the 'puter.

And I know people I can get help from whenever I attempt this.

UnloadeD · 04-03-2003, 06:44 PM

Well, I'm not sure if yours will be the same. It should be the black and white wires you want, but best to put a meter on just to be sure. Yes, you'll be able to run the pump with the puter off.

peace.
unloaded

CheeseBall · 04-04-2003, 07:22 PM

One last question: Since the power to the pump is coming from the AC switch. It wouldn't neccesarely be taking power away from the 550W in my PS. Or would it?

UnloadeD · 04-05-2003, 03:45 AM

No, it would be the same as having both devices plugged into the same wall outlet.

peace.
unloaded

CheeseBall · 04-05-2003, 04:21 PM

Awesome, ok ok one last, last question.

Why did you decide to run the green wire through the molex? All this does is not let the computer start unless the molexs are plugged together, correct?

So I could just wire a regular female plug onto the black and white wires from the PS switch and plug my pump into that correct?

You have been much help to me thanks alot.

UnloadeD · 04-06-2003, 07:26 AM

Quote:

Originally posted by CheeseBall
Awesome, ok ok one last, last question.

Why did you decide to run the green wire through the molex? All this does is not let the computer start unless the molexs are plugged together, correct?

So I could just wire a regular female plug onto the black and white wires from the PS switch and plug my pump into that correct?

You have been much help to me thanks alot.

The green wire is optional. I use it as a safety feature so there is no way to run the puter without the pump connected (and running). I do have a second "dummy" molex that has the green wire only. If I wanted to run my system on a HSF I would use the dummy and not plug in the pump.

peace.
unloaded

DigitalChaos · 04-07-2003, 12:54 AM

most pumps are designed to be run all the time... the turning the pump on and off will put alot of stress on the pump... i would suggest only turning the pump off for maintenence or an extended period of your computer being off

think fish/pond pump.... thats what most of these pumps are.. and how often are you turning those on and off?

piggy backing the 120 AC connections inside your PSU is probably the best way since both of the above conditions will = no power to the computer. that way either disconnection the cord from the psu.. or hitting the power to your powerstrip will kill the pump.

03-29-2003, 02:46 AM	#1
KlevrPhelo Cooling Neophyte Join Date: Aug 2002 Location: San Diego, CA Posts: 18	To relay or not to relay? That is the question! First off.. I'm pleased to announce that my very first water cooled rig is well under way... WOOT WOOT! After almost a year of planning and modding the case, it's finally coming down to the wire. I would like to say many Thanks to any and all who've responded to my posts that helped me along the way! Now... on to my question: I'm debating on whether or not I should put a pump relay switch on my machine. I like the idea of being able to turn off the pump with when turning of the machine... but on the other hand, I would like to have the option of turning on the pump without booting up the computer. Any suggestions? __________________ I'm a newb... can you tell?

03-29-2003, 06:03 AM	#3
max Cooling Neophyte Join Date: Dec 2002 Location: New Zealand Posts: 64	I used a solid state relay which was quite cool, no sound etc __________________ My Watercooled A t h l o n X P My homepage My Trademe Auctions

03-30-2003, 10:46 PM	#5
max Cooling Neophyte Join Date: Dec 2002 Location: New Zealand Posts: 64	I cant remember the model of mine and i got it in new zealand - where i live. They are not uncommon and have heaps of different brands/models to choose from (just like normal relays), just make sure it has the right voltages eg mine: 100-300 VAC and 3-30 VDC to switch it __________________ My Watercooled A t h l o n X P My homepage My Trademe Auctions

03-31-2003, 09:39 AM	#8
TerraMex Cooling Savant Join Date: Nov 2002 Location: Portugal, Europe Posts: 870	Relay. I have one , and did the same thing that Hara did, i have two switches: - Switch 1 , in the 12v side of the relay. When on, the PC is on, the pump is on. Off, the pump stops, even with the PC on. - Switch two, in the 220v side . When on , the relay depends on the above switch (1). When off, the pump is kept working independent of the state of the relay, so its a bypass. Works great. __________________ "we need more cowbell."

03-31-2003, 06:11 PM	#9
airspirit Been /.'d... have you? Join Date: Jul 2002 Location: Moscow, ID Posts: 1,986	Check this out: http://www.criticool.com/Powerplant.htm It fits in a PCI slot, pulls power from the PSU (molex connector), and relays to the pump. Installation should take about five minutes. Strip your wires, screw them in, fire the computer up, and you're running. It is more expensive than the radio shack method, but having done that myself, I don't know that I'd want to deal with that again. This is more idiot proof, and looks a hell of a lot nicer in your system. __________________ #!/bin/sh {who;} {last;} {pause;} {grep;} {touch;} {unzip;} mount /dev/girl -t {wet;} {fsck;} {fsck;} {fsck;} {fsck;} echo yes yes yes {yes;} umount {/dev/girl;zip;} rm -rf {wet.spot;} {sleep;} finger: permission denied

03-29-2003, 02:57 AM	#2
Althornin Cooling Savant Join Date: Dec 2002 Location: Houston, TX, USA Posts: 221	pick up a cheap relay from Radio Shack (cost, about 3 bucks) and wire a switch in parralell with it. leave the switch off for normal (computer on --> pump on, computer off -->pump off) operation, and turn it on for straight "pump on" operation. cost to you: about 5 bucks and 15 mins of wiring.

03-30-2003, 10:34 PM	#4
CheeseBall Cooling Savant Join Date: Jan 2003 Location: Colorado Posts: 176	I am wanting to wire up one of these also. What is the model number of the relay you used max? And where can I get it. I heard maybe allelectronics.com and bgm.bgmmicro.com, or will radioshack carry it. Also, if someone could post a model # for a good switch that would be great also. Thanks a load, Bryan

03-30-2003, 11:55 PM	#6
Althornin Cooling Savant Join Date: Dec 2002 Location: Houston, TX, USA Posts: 221	The radioshack relay you would want would be this one: RadioShack Relay 275-218 Then any 120VAC switch (that handles enough current). Apparently relay price has gone up since i purchased. But any 12V switched relay will work fine, in parallel with a switch, to do exactly what you want. Example switch: RadioShack Switch 275-666 Note that this switch can handle 3 amps at 120VAC, and the relay is good for 10 amps at 120VAC. Both are extreme overkill (power handling wise) for this project (running a pump that uses what, 20 watts = .2 amps at 120VAC) but thats not nessesarily a bad thing. If you can find a cheaper relay/switch that more closely meets your power requirements, then go for it.

03-31-2003, 06:34 PM	#10
UnloadeD Cooling Savant Join Date: Oct 2002 Location: MidWest USA Posts: 176	I didn't use a relay. I tapped into the AC of my psu's switch. Connected it to the pump with a molex, while I was in the psu a cut the green wire going to the motherboard and ran it thru the two blank spaces left on the molex. All of this serves a few purposes I was after: 1) one power cord out the back of my puter 2) if psu is ON pump is ON 3) if pump isn't plugged into psu, the puter won't start. All my needs were met and it was easy and really cheap, because I already had the needed parts on hand. I can turn on the pump without turning on the computer, I can't turn on the computer without the pump. Here's a simple pic: edit: another pic peace. unloaded

04-01-2003, 01:43 PM	#12
CheeseBall Cooling Savant Join Date: Jan 2003 Location: Colorado Posts: 176	Unloaded I like the way it works, but I dunno if I wanna try it. Can you post more details of how exactly you did it? I have done some automotive and home electrical wiring but the thing is I dunno if I wanna open up my PS. Oh yeah, and is there a good way that isn't too complicated to power the pump w/ your PS while using a switch and relay. And not opening up the PS? I don't wanna get to advanced so I'm guessing probably not.

04-01-2003, 04:26 PM	#13
airspirit Been /.'d... have you? Join Date: Jul 2002 Location: Moscow, ID Posts: 1,986	The bare leads for 120VAC and 12VDC (req. for the pump and relay) are inside your PSU. You cannot access the 120VAC from outside of the psu unless you have a passthrough plug and you don't mind chopping a power cable. The bare 120VAC leads are normally positioned in your PSU in a way that limits the risk of damage to any other components ... unless you're afraid of voiding your warranty, you should at least make your decision after popping it open and looking at what it would take to wire in your pump wires. __________________ #!/bin/sh {who;} {last;} {pause;} {grep;} {touch;} {unzip;} mount /dev/girl -t {wet;} {fsck;} {fsck;} {fsck;} {fsck;} echo yes yes yes {yes;} umount {/dev/girl;zip;} rm -rf {wet.spot;} {sleep;} finger: permission denied

04-02-2003, 01:03 PM	#15
airspirit Been /.'d... have you? Join Date: Jul 2002 Location: Moscow, ID Posts: 1,986	With a good relay, you shouldn't burn your PSU if the pump is unplugged, as there wouldn't be any 120VAC passthrough ... but without knowing the exact setup of your relay, that is a concern. As far as the premade kits, you can always purchase a three prong female 120VAC plug and wire that directly into the three screw connectors on that kit I referred to above. That costs about $1.50 for the plug. Then you can just plug the pump into the card without cutting your pump's cables ... I did something similar by modding a power strip when I installed a dimmer for my 120VAC fans ... I modified the cable going to the power strip and put the dimmer inline there, leaving me with a dimmed power supply that I could just plug my fans into. There was no way in hell I was going to modify such expensive fans. All I have to do is plug in the power strip (the dimmer circuit is mounted externally and the strip is internal), plug the fans into that, and I have speed-regulated AC fans. __________________ #!/bin/sh {who;} {last;} {pause;} {grep;} {touch;} {unzip;} mount /dev/girl -t {wet;} {fsck;} {fsck;} {fsck;} {fsck;} echo yes yes yes {yes;} umount {/dev/girl;zip;} rm -rf {wet.spot;} {sleep;} finger: permission denied

04-03-2003, 02:28 PM	#16
CheeseBall Cooling Savant Join Date: Jan 2003 Location: Colorado Posts: 176	I understand your drawing (I think), I just need to know how to find out which lines to wire into on the PS switch. From your picture I can tell the lower one is live but will mine be the same? The male plugs are already on the switch correct, or did you have to mod them? If they aren't there I might not try this. Also, if you shut down your computer, but the switch on the PS is still on. The pump will still be running correct? So I would be able to fill/bleed everything, right? Then once I am done bleeding, just hit the power button on the front of the 'puter. And I know people I can get help from whenever I attempt this.

04-03-2003, 06:44 PM	#17
UnloadeD Cooling Savant Join Date: Oct 2002 Location: MidWest USA Posts: 176	Well, I'm not sure if yours will be the same. It should be the black and white wires you want, but best to put a meter on just to be sure. Yes, you'll be able to run the pump with the puter off. peace. unloaded

04-04-2003, 07:22 PM	#18
CheeseBall Cooling Savant Join Date: Jan 2003 Location: Colorado Posts: 176	One last question: Since the power to the pump is coming from the AC switch. It wouldn't neccesarely be taking power away from the 550W in my PS. Or would it?

04-05-2003, 03:45 AM	#19
UnloadeD Cooling Savant Join Date: Oct 2002 Location: MidWest USA Posts: 176	No, it would be the same as having both devices plugged into the same wall outlet. peace. unloaded

04-05-2003, 04:21 PM	#20
CheeseBall Cooling Savant Join Date: Jan 2003 Location: Colorado Posts: 176	Awesome, ok ok one last, last question. Why did you decide to run the green wire through the molex? All this does is not let the computer start unless the molexs are plugged together, correct? So I could just wire a regular female plug onto the black and white wires from the PS switch and plug my pump into that correct? You have been much help to me thanks alot.

04-07-2003, 12:54 AM	#22
DigitalChaos Cooling Savant Join Date: Jan 2002 Location: Waukesha, Wi Posts: 698	most pumps are designed to be run all the time... the turning the pump on and off will put alot of stress on the pump... i would suggest only turning the pump off for maintenence or an extended period of your computer being off think fish/pond pump.... thats what most of these pumps are.. and how often are you turning those on and off? piggy backing the 120 AC connections inside your PSU is probably the best way since both of the above conditions will = no power to the computer. that way either disconnection the cord from the psu.. or hitting the power to your powerstrip will kill the pump. __________________ http://www.digitalsimplicity.com/eatme/

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