How to turn off comp when there is no flow?

[Maximilium]

Hello

For the past month I have been searching the net, I want to build a water-cooling system for my computer (my first water rig).

So far I have been able to gather enough information, and I already started buying the parts.

The pump:
http://www.go2marine.com/frameset.js...egoryId/11659/

The radiators (3):
http://www.dangerden.com/mall/Radiators/hwlabs.asp

The header tank:
http://www.wizarddesigns.co.uk/restanks.htm

Start-up delay (to start pump before CPU after some modifications)
http://www.cooltechnica.com/Merchant..._Code=Electric


Shutdown protector (to keep pump running for 1 min after turning of computer, after some modifications)
http://www.pcmods.com/index.asp?Page...ROD&ProdID=340


The flow switch


The task: Making everything on this list work together.

But there is 1 problem that I have been trying to solve, how make the computer to shut down in case my pump stops working?

Everything was working smooth (inside my head at least) until I found a problem, if I use signal coming from the radiator fan (rpm signal) going by the flow switch when is closed (with flow) and connecting it to the CPU fan @ the motherboard, the bios will detect the signal and it will boot up the system.

But, after the system is up and running and pump fail = no flow = no rpm signal, the computer wont shut down. The only way to monitor the signal and make computer to shut down is with 3rd party software, like MB5, something I don’t want to be using while I am running my com.
So, for the last week I have been trying to solve this problem before I put everything together, the solution maybe simple but I need the know-how, here is my input:

Using the flow switch to activate a 12v relay when there is no flow, this relay will then make the contact between the cables for the power button of the computer, doing this for 4 sec = computer off. After, relay must deactivate to prevent turning the computer on issues.

When I learn how to post pictures I may do a schematic of what I am writing about.

Any suggestions?

[fhorst]

I'm amazed of all the quality stuff you will put in.

Answer to your question:
- If you use a P4, and you are not using pelties, you have "nothing" to worry about. Your CPU will get to hot, but it will turn off the computer before your cpu or other components will Die. (The P4 has a thermo protection)

- Use the CPU temperature limit in the BIOS (you can set it to 50 degrees celcius), If it get's above that, you can set to a warning, and a shut down 5 or 10 degrees higer.

- In almost all bios you can set "shut down at cpu fan fail" You can use this (with the rpm from the flow switch), but then you need to be sure that the RPM value is constant. (With the flow meters you can buy, the rpm ain't constant, the signal stops from time to time...,so you can not use them)

just my 2 cents.

[Maximilium]

using the 4 sec hold power buton shut down, i think this may work.

[Maximilium]

It looks simple, but there is more work to be done (like testing, making sure computer won’t turn on by itself ext...)

Fhorst, thanks for your answer, I will be using a P4, but what I am trying to do is making a system that can turn off by itself without using 3rd party software in case of pump dies, and yes, the bios can detect temperature and it has "shut down at cpu fan fail", but the problem with this is :

(1) You boot up, bios detect fan speed and temperature, if is ok, computer turns on, if not computer don’t boot up.
(2) After computer boots up, I can actually disconnect my cpu fan from motherboard and nothing happens, after boot up the only way to monitor fan rpm is apparently with a 3rd party software like MBM 5.
(3) Maybe not all motherboards are like this, I am using a P4T533 from Azus and I am thinking to upgrade to Abit IC7-G Max 3, I don’t have it yet so I cant answer yet if the same problem is also present with this motherboard but for what I read, after operating system takes control of your computer, bios protection goes “out the window”.

[BillA]

this switch will give you a 'hard' shutdown if connected to the mains
- but could be wired many other ways
look for a smaller version ? (3x2x5")

[Maximilium]

Here are the specs on that switch


Is a good pressure switch to mention, at my work we use them on electric welders, they are big and made to handle high currents, the flow switch I have in mind, small, easy to install inside my case.

[BladeRunner]

Maximilium

I decided to reply to your PM here as it contains usefull links etc.

I hadn't thought of doing it via the case button, In theory it should work just fine and the relay won't need to power off after 4 seconds as the shut down will depower it as the psu shuts off.

The relay may work by simply running the power for it through the flow switch. It could give start up issues but I doubt it.

For intersts sake I favour the soft shut down for the momment as it shuts off the PC properly. If I use the case button shut off XP looses temp internet images....... a real pain when on a slow connection.

anyhow I like the idea and would be good for tec use. Unless using a tec the 1min pump run on is not requred.

http://forums.procooling.com/vbb/sho...&highlight=joe

You may find the above useful as it is a true (instant) hardware shut off, but like I doubt it would save a block falling off the CPU failure because PSU's take a second or two to "drain" even if you pull out the power lead. It would certainly avoid a Tec melt down situation though.

The article link in the above topic is dead now but I've found the article here.

http://www.procooling.com/articles/h...hutdown_ho.php

Another thread that is worth reading, (or printing out & reading as it is very long), is this one on the damage a high watt Tec can cause when the flow stops. It's titled "pump death" but in talking to the guy, (I fixed his maze 2 that got so hot it unsoldered!!), I think it was actually user error, (not plugged in).

http://www.over-clock.com/cgi-bin/ik...ST;f=24;t=1085


To sum up I like to have protection circuits, but still think the major effort needs to be put into the design & build of the water-cooling systems its self, with regard to choice of parts, connections, blocks, testing, etc when initially building the system and not rushed. This is where it's most likely to be determined if you will have any many future problems. From what I've seen and read most leaks, disasters, problems, etc are user error caused, often because it is either rushed or approached from the "how cheaply can I water-cool my PC" angle, rather than the "how is the best way it can be done effectively, without it costing me too much"

These threads have some general input on that topic

http://forums.procooling.com/vbb/sho...&threadid=7239

http://forums.procooling.com/vbb/sho...&threadid=7079

[Maximilium]

BladeRunner,

Thanks for the quick responce and the usefull input.

I updated my list since i had the wrong flow-switch, i found one that is normaly closed (close at no flow), it took me 3 days to find it.

The flow switch

The reason i will like to use the start-up delay is simple, to make the pump run, flow switch to open before the bios check (adjusting the delay for 2 sec i think will do the trick), eliminating start-up problems (still need to be tested-parts on the way).

[BladeRunner]

I get what you are saying but I don't think it would be an issue without the delay. When I press my power switch on the PC the click of the "bobbin" rising in the flowswitch is near instant, and in my set-up the pump is powered by a 12v relay in the PSU, so that all takes time.

The flow switch you link to sounds fine, straight through rather than a 90 would have been nicer, and it would be nice to know what it looks like inside.

[Maximilium]

the flow switch that i had in mind works, but it sucks, to much flow restriction.


now to plan B....






http://www.proteusind.com/headerlinks/price_list1.html

more updates after i get one of this things

[killernoodle]

Adjusting the bios in most computers turns them off automatically when your CPU gets too hot. If you are going to run a peltier, a relay connected to the A/C plug of the power supply will turn off the pelt when the computer shuts down from overheating. Flow switches are basically a waste of money in your case.

Also, most waterblocks are able to absorb alot of heat before the CPU temp goes up too much, especially with a lot of water in them. I have a gemini-cool high flow model (replacing soon) that can run my computer for 1 minute before shutting down at 155F from an idle temp of 80F with the pump turned off, and the CPU is at 1.9V and 2.63ghz and the waterblock is much smaller than most.

I just dont get why you think you need this much saftey:shrug:

Especially the thing that turns off the pump after the comp is off, its rediculous.

EDIT: Bladerunner, dont you have enough stuff packed into your computer already? I remember seeing pics of it, it looks like a circulatory system with a heart and a whole bunch of arteries and veins and stuff. Too complicated for simple ol' me.

[BladeRunner]

killernoodle

That's fine if the bios heat shut off always worked, but it doesn't always in my experience, and its not much use if the CPU has crashed due to the heat up. I run my CPU overclock close to the coolant temp as I have pretty stable and low year round temps with my cooling set-up. Bios overheat shutdown also requires a secondary reaction to occur where as we prefer an instant reaction to the pump fail event, I have a heat shut down enabled as a second back-up but don't want to rely on it.

Also my plan is to use Tec cooling at some stage and they can get to solder melting temps far quicker than you might think if the water flow stops.

Running the pump for a min after the comp is off isn't required, but a short delay could be good when using a high watt Tec?

The flow protection is quite simple, and the water-cooling is not as complex as it appears, how would you suggest supplying 7 separate waterblocks with coolant, in a more effective way?

[killernoodle]

Fill the whole computer with water? Well, I know it isnt as complex as it appears

I see now what you mean about the tecs, it would be a good idea for some extra protection in that department. I have seen/read all the horror stories about pump failures when using tecs, and I also see your concern now.

[BladeRunner]

killernoodle

No you do have a valid point, and I do have a bad habit of looking at things from my perspective only. In theory a heat level set in something like motherboard Monitor to turn off the PC at a certain temp should work ok. As said the bios shutoff doesn't normally allow a low enough setting temp for people using water cooling with chilled coolant........

Part of the reason as said is to have an instant reaction to pump fail or flow loss, and it makes me much happier leaving the PC unattended for periods during the day. The other is some of us just like solving stuff and hopefully improving things. I do need to get the motherboard monitor software shutdown part solved before using a Tec, I may build the PSU power down circuit as shown in the link I posted, as it seems the most instant way when running a TEC. In theory it should give power down in 1 to 2 seconds if the flow stops......

[nexxo]

Actually on my project I looked into the same issue. What I and Bsodmike came up with was the following:

A flow switch which can be found at Royal Components :here:

This one has 3/8" NPT screw thread, has very little flow resistance and is sensitive enough to trigger (flow=on) at low flow (see it fitted here in my modified Aquatube Res).



And a little PIC designed by Bsodmike. This monitors the PC status (on/off), checks flow and shuts the computer down (either over PowerOK wire of the PSU, or via the power button as discussed above) in the case of a pump failure. It also controls the power led: in PC Off it pulses blue, in PC On it shines blue, and in pump fail it changes to red.



So that is how we solved that problem. The pump by the way is a 12V item that switches on with the PC, but of course you can use any type you want.

[Maximilium]

Thanks nexxo ,

Thats a nice card you have there. Can you tell me, the flow switch you are using is a normaly open (close with flow), how you was able to made the circuit?

can you post more information on that card?

[nexxo]

The switch is indeed open at rest and closes when flow is present.

The PCB is a home-brew by bsodmike (a.k.a. Dr Mike) with some design suggestions by myself. It has a simple programmable interface circuit at its heart. He made a number of these things and sells the kit for about £35,--. You have to be confident to splice into the purple wire of the PSU's mobo connector though (allways-on 5V which feeds the circuit), but otherwise wiring it up to a PSU molex and the power button leads is easy-peasy.

You can reach Dr Mike through his e-mail in his profile (of his Project Log thread) :here:.

[RoboTech]

You might find some useful info in this article: "Controlling Pumps and Initiating Emergency Shutdowns" (for water-cooled PCs)...

http://www.overclockers.com/tips1120/

RoboTech

[nexxo]

Great link, and great work, Robotech! A really useful article.