need a 1/2" flowmeter

abyssling · 11-11-2002, 09:25 AM

Hello all, Abyssling from Pimprig here.

I was wondering if you guys could give me a hand with something, I'm looking for a flowmeter with 1/2" fittings. Not a 3/8 with 1/2 adaptors, but a true 1/2" flowmeter, anyone here know of a good one? I've used the Innovatech one and it is too restrictive for my current setup and I have searched your forums and can only find the 3/8 ones.

One with a digital readout I can port to my lcd would be preferable, but not necessary

Thanks a ton.

bigben2k · 11-11-2002, 09:37 AM

Welcome to ProCooling!

I've been looking at many flowmeters over the past couple of months, and received some specs too.

First, I have to point out that the more accurate they are, the more expensive they are!

I have yet to find a nice inexpensive, unobstructive flow meter with some (any!) kind of electrical (or electronic) readout, but if I come across one, you'll be the first to know!

I've also been looking into "flow sensors", something to tell me if there is flow or not, that generates a signal that could be used to shutdown the PC. No cheap luck there either.

So the first thing you want to do is determine the purpose, and a budget!

BTW, flow meters that have a visual sight are common and cheap.

mfpmax · 11-11-2002, 10:14 AM

There is an article on Overclockers.com about making a flow meter...electronic

abyssling · 11-11-2002, 10:25 AM

I need a reliable flowmeter for my test box WC rig

It is an asus a7m266-d with the mounting holes drilled out, running dual 1900MPs in serial, currently cooled by MCW372s in a 1/2" setup using a BIX and an Eheim 1250. I want to be able to measure flow accurately to gauge the flow capabilities of blocks and other hardware that I test, as well as try to mod a failsafe shutoff when my flow drops below a certain level. I am aware that I have other bottlenecks in my system currently but I am just trying not to add any more at this point, as I will be testing some true 1/2 setups and do not wish to compromise my data.

Price is not a major object for me as long as I can stay under 200 to 300 dollars US I am not too concerned. I need accuracy and ease of readout first and foremost.

Also, before you ask why I use a dually for a WC test bed, I have 2 reasons.

Number one, I can always unhook 1 proc and run single cpu tests, and still have the option to run comparison testing in dual mode, as well as test various setups in parallel and serial. Contrary to popular belief, serial is not ALWAYS the most efficient, especially in high flow rate setups. I have found that I can somewhat gauge a block's flow capacity by comparing my parallel temps to serial, but obviously it is not extremely accurate.

Number two, because its pimp as shiz, and thats what we are all about at pimprig

*edit* Thanks, I'll be sure to check it out! and I appreciate the welcome Bigben, I've always heard great things about you guys

bigben2k · 11-11-2002, 10:42 AM

Quote:

Originally posted by mfpmax
There is an article on Overclockers.com about making a flow meter...electronic

I believe that you're referring to this article by LMandrake (aka Otto Matheke ).

Personally, I'm not too fond of the cork plug, but that isn't anything that can't be fixed with some epoxy.

BTW, that's a flow sensor, not a flow meter.

gone_fishin · 11-11-2002, 11:34 AM

I believe you are looking for something like this?

http://www.blue-white.com/Products/E...p?pipeSize=3/4"
Price is probably up there for a new one though.

I don't know how appropriate these would be. click

bigben2k · 11-11-2002, 11:47 AM

I e-mailed the sales team, for Model Number: AOS175M2GPM2
(first link). I asked for specs and pricing.

The second one looks OK, but rated for a pressure that way up there. There must be a cheaper alternative, but $160 is probably as good as it gets, with some kind of accuracy.

pHaestus · 11-11-2002, 11:52 AM

oops I thought you meant for testing. For show and tell I think the Swissflow unit is best, but pricey and requires import from Switzerland.

nexxo · 11-11-2002, 12:58 PM

Several threads exist on this subject. One referred to Dwyer as the place to go and it is indeed recommended! Check these babies out for example:

Both have 1/2" connectors and work on 12V.

I found a couple of useful ones on RS-Online; a cool-ass flow indicator...

(the metal bits are sold seperately and some accomodate 1/2" connections)

... and two flow sensors. This one

operates on 5V and senses upto 20 l/min flow (a 300 GPH pump produces 18 l/min). It emits 750 pulses per litre flow; at 18 l/min that is 13500 pulses per minute; similar to a (admittedly very fast) CPU fan. Connections are 3/8".

This one

has 1/2" connections, runs on anything between 4.5V and 24V, and emits 23 pulses per second at 12 l/min flow. At the aforementioned 300 GPH (18 l/min.) that is 2175 pulses per minute, i.e. similar to a somewhat slow CPU fan.

The idea is that when flow stops, so do the pulses, similar to a fan stalling. This should prompt the mobo to perform a shutdown.

pHaestus · 11-11-2002, 01:20 PM

Way too much $$ new.

Check www.labx.com or www.ebay.com for used flowmeters. Try and get one that has been calibrated recently.

You will be able to find digital flowmeters that output 4-20mA signal. Then buy a an LED display (called an indicator I think) to convert such to flow rates. Should be under $50 for both if you are patient.

The dwyer stuff looks nice though. I have a GPI paddle wheel type.

Alchemy · 11-11-2002, 02:44 PM

If you want to go the cheaper route, and you have a bit of space to work with:

http://www.omega.com/Green/pdf/FL1340_1440.pdf

Rotameters!

Alchemy

[edit - odds are, you're going to want higher flow rates than that, though]

bigben2k · 11-11-2002, 02:59 PM

More flow rate indeed! At 2L/min max (0.5 gpm), it's quite useless, at least for me (shooting for 4 to 6 gpm).

Also, these units are either Alu (bad for my all copper), brass (OK) and Stainless Steel (OK). Personally, I'd rather have an all plastic solution (it's cheaper too!).

nexxo · 11-11-2002, 05:06 PM

Some of the aforementioned units are plastic, and reasonably cheap, and will handle 4/6 GPM. Really guys, you can't get better than these.

bigben2k · 11-11-2002, 05:23 PM

Not bad indeed. At $70, where it can be used both as a meter and sensor, that's definitely attractive.

BillA · 11-11-2002, 06:12 PM

anyone looked at the pressure drop curves for these things ?
ask the mfgrs, they ALL have them

you will be quite dismayed, big time

I have owned and used every type
start by understanding that well over 1/2 of your pump capacity will be 'dropped' across the flowmeter
so you cannot use a 'normal' pump
and it goes on and on

gone_fishin · 11-11-2002, 06:38 PM

Quote:

Originally posted by unregistered
anyone looked at the pressure drop curves for these things ?
ask the mfgrs, they ALL have them

you will be quite dismayed, big time

I have owned and used every type
start by understanding that well over 1/2 of your pump capacity will be 'dropped' across the flowmeter
so you cannot use a 'normal' pump
and it goes on and on

This one says no pressure drop. Are they full of it or can it be true?

pHaestus · 11-11-2002, 06:54 PM

I dont see how a paddle wheel type flowmeter could have no pressure drop....

BillA · 11-11-2002, 11:00 PM

and equally amazing is this:

"Full scale accuracy: +/- 1%"

that would take some certified results to convince me
with paddle wheels the greater the accuracy, the greater the head loss

BladeRunner · 11-12-2002, 04:26 AM

Hi guys, It's true most commercial flow meters are either far too expensive or restrict the flow down to a tiny hole. They also mostly work by spinning an impeller which makes a noise. As I was only after a flow "monitor" not a flow "meter" I made this auto shutoff system, works really well using this, (cheapish, £13 UK), flow switch shown below, bought from RS in the UK, which uses the same principal as the proximity switch shown in my previous posting in this topic HERE

Here's my description of how it works:-

Inside the tube it has a small plastic cylinder which sits on the base of the unit positioned in the branch off part. Inside this plastic cylinder is a small magnet. The "cap" at the top of the Y branch has a proximity switch. When the pump is not running the plastic cylinder sits on the base of the unit so the contacts of the proximity switch remain open. When the pump is on the flow pressure makes the cylinder rise up into the branch so causing the proximity switch to close contacts. (there are two versions, 22mm and 15mm), I used the 22mm so it wont cause any overall flow restriction)

The output from this is run to a "pulse Generator" unit which is a small cheap & simple electronic circuit I made, (with much help from others), to mimic a fans sensor output, so I could use the original "Smart Doctor" utility with my Water-cooled Asus GeForce 3, (with the GF3's fan removed, smart doctor would pop up all the time saying the fan was dead, and there was no way to disable it).

Here is an image of the "pulse gen"

It plugs into the CPU fan header on the motherboard. The sensor output from the "pulse gen" is run through the flow switch so when the pump is running the motherboard reads about 3000rpm just as if a fan is plugged into it. If the pump dies or the flow is interrupted by coolant loss, or flow is low etc, the cylinder in the flow switch will drop down and the proximity switch inside will go open circuit cutting the sensor output to the fan header. This will cause the bios to read 0 rpm and instantly shut the PC down if the bios option is set to "shutdown on CPU fan fail".

I've since found there is a slight problem with this on my motherboard, (Abit KX7 333R), in that the bios setting for "shutdown when CPU Fan fail" doesn't actually work, (It is enabled). It's also nothing to do with my "pulse gen system" because even with no fan connected it doesn't shutdown. I'm therefore using "Motherboard Monitor" with "Shutdown now" set to force shutdown in 0 seconds on no CPU fan rotation. This works fine and shuts off the PC within a few seconds if the Pump or flow is stopped. A bit of an ass about face way of doing it, but until I can find out why the bios setting doesn't work it will do.

The flow switches can be found on the UK RS site, (http://www.rswww.com), by typing this code C257076 into the search feature.

You don't have to use a pulse gen, but can just use a fan as long as it can be run from the motherboard CPU fan header. If you are fanless like myself, then here is the circuit diagram for the pulse gen, with components required.

Wire trace colours used mainly just to show where they pass each other but are not joined, (they are only joined with a circle).

more detail on this in the linked topic at the beginning

If you don't need to have a fanless solution the pulse gen unit is not required. It is then very simple to wire up all you need to do is cut one wire and make two wire joins. This very poor sketch should make it clear

This will mean when the pump is creating flow the contacts in the flow switch will be closed so the fan will output it's RPM to the motherboard in the conventional way via the flowswitch. If flow stops, or drops too low, pump dies, coolant loss etc the contacts in the flow switch will open so the fans rpm output will be switched off causing the mobo to read zero rpm just as if the fan had stopped working, (although the fan will still be running).

The only other things you will need are Motherboard monitor (free), and shutdown now which is free for 2 weeks then costs $19 USD, (make sure you buy it because it doesn't tell you it's stopped working it just pops up a window rather than shutting down). At least you'll have two weeks to get it working and decide if it's what you want.

So total cost:-

Fan (I'd assume you had one but $5)
Flow switch $18
shutdown now $19

total $37 usd without fan, plus a few hours work and maybe some tube, tube clamps and reducers.

not much for piece of mind

(if anyone does this, motherboard monitor wont allow a setting of 0 seconds to shutoff on CPU fan fail, lowest is 10 seconds but it's quite easy to edit the inf, ask if you need to know how).

The beauty is it will power your system off in the correct way if you are not around in event of a failure, so saving your data. If I were running a high watt TEC I'd probably make the system just power off the PSU instantly to be safe.

MadDogMe · 11-12-2002, 04:53 AM

Did you ever get a reply from Abit about the 'auto shutdown~CPU fan~fail' option not working?. mine will prevent the system booting if no fan is detected, but won't shutdown once windows has loaded.

Is there a way the magnetic switch on the sensor could be rigged to a '240V mains trip switch'?(turn the whole lot off!), those plug in safety things you use for garden tools, ect...

Or a relay if you could build a delay into it?, to give the pump a chance to power~on and start flowing before the switch turns the relay off!...

Quote:

If I were running a high watt TEC I'd probably make the system just power off the PSU instantly to be safe.

Run the TEC~PSU off a relay with the pump?(from the PC's 12v line)...

BladeRunner · 11-12-2002, 05:04 AM

I never got any replies from Abit, (sent it a few times). Didn't really expect a reply I suppose. It does seem to work fine with shutdown now though, I test it a few times each week by shutting the pump off to make sure it works ok.

The flow switch after all is just that, a simple make or break set of contacts so you could switch anything with it. It's rated for mains voltage, but I'd rather switch a 12v relay to swich the mains remoltly if I wated to do that. You could of course run the ATX "power up" wire through the flow switch that would be an instant shut down, but the delay on flow start up might cause this to be problamatic. The other option is to use the flow switch to control an adjustable time delay relay, they are pretty easy to make.

MadDogMe · 11-12-2002, 05:13 AM

I like the relay~mains idea best as well, turn everything off, pump/TEC/PC the lot!. any chance of a schematic/drawing on how to make a timer curcuit for 'the unwashed' like me?

. what chips, parts needed kindof thing. it's the thing every H2o rig should have, especialy if a TEC is used. make a good article. specialy if the sensor is as cheap as £13!, timer included would'nt top £20 probably!...

BladeRunner · 11-12-2002, 05:36 AM

I'll see what I can come up with but it's a bit like the blind leading the blind! I'm no electronics expert, I usually just find a way to do what I need to somehow

, Maplin do various 12v delay relay kits btw.

Like you say instantly pulling the power to everthing is the best way if you have a TEC. There was a good article about an instant PSU shutoff system in this forum about a year ago that used a temp sensor so it would shut down if the heatsink fell off the CPU. That circuit could be made to work with the flow switch I guess.

How have you done yours btw, with the same flow switch as me?

MadDogMe · 11-12-2002, 08:15 AM

I'm still trying to get my rig all in the case!. I have to take things step by step due to severly limited funds :shrug:. I'll probly use the same flow sensor because of the cheap cost

. is it very restrictive?, has it got a spring inside?, or is it gravity/airtight~pressure that opens the connection?...

Thinking about a relay for the 240AC, it'll be hard to switch on because the power is'nt going to be there to activate a timer!. if only it'd only close/open the connection on the relay while the PC is powered. if you know what I mean.

a simple push and hold button would work!!, if it shorted/bypassed the connections on the relay while held down (as well as turning the PC on!), it'd have to be held down long enough for the pump to start flowing>sensor~ switch to close> relay to make connection, what do you think?, be easier would'nt it?...

BillA · 11-12-2002, 08:39 AM

BladeRunner
as usual your work is quite excellent, kudos

MDM
why not a couple of relays in sereis with a solid state time delay between them ?

11-11-2002, 09:25 AM	#1
abyssling Cooling Neophyte Join Date: Nov 2002 Location: roanoke, va Posts: 9	need a 1/2" flowmeter Hello all, Abyssling from Pimprig here. I was wondering if you guys could give me a hand with something, I'm looking for a flowmeter with 1/2" fittings. Not a 3/8 with 1/2 adaptors, but a true 1/2" flowmeter, anyone here know of a good one? I've used the Innovatech one and it is too restrictive for my current setup and I have searched your forums and can only find the 3/8 ones. One with a digital readout I can port to my lcd would be preferable, but not necessary Thanks a ton.

11-11-2002, 09:37 AM	#2
bigben2k Responsible for 2% of all the posts here. Join Date: May 2002 Location: Texas, U.S.A. Posts: 8,302	Welcome to ProCooling! I've been looking at many flowmeters over the past couple of months, and received some specs too. First, I have to point out that the more accurate they are, the more expensive they are! I have yet to find a nice inexpensive, unobstructive flow meter with some (any!) kind of electrical (or electronic) readout, but if I come across one, you'll be the first to know! I've also been looking into "flow sensors", something to tell me if there is flow or not, that generates a signal that could be used to shutdown the PC. No cheap luck there either. So the first thing you want to do is determine the purpose, and a budget! BTW, flow meters that have a visual sight are common and cheap. __________________ WBTA (Water Block Testing Alliance) Nordic Hardware WC 101

11-11-2002, 10:14 AM	#3
mfpmax Cooling Savant Join Date: Oct 2000 Location: Rockledge,FL,US Posts: 731	There is an article on Overclockers.com about making a flow meter...electronic __________________ My old and retired watercooling setup. Watercooled K6-2 450 at 600 Also Retired - Watercooling an XP1800@1782MHz

11-11-2002, 11:34 AM	#6
gone_fishin Cooling Savant Join Date: May 2002 Location: Da UP Posts: 517	I believe you are looking for something like this? http://www.blue-white.com/Products/E...p?pipeSize=3/4" Price is probably up there for a new one though. I don't know how appropriate these would be. click Last edited by gone_fishin; 11-11-2002 at 11:40 AM.

11-11-2002, 11:47 AM	#7
bigben2k Responsible for 2% of all the posts here. Join Date: May 2002 Location: Texas, U.S.A. Posts: 8,302	I e-mailed the sales team, for Model Number: AOS175M2GPM2 (first link). I asked for specs and pricing. The second one looks OK, but rated for a pressure that way up there. There must be a cheaper alternative, but $160 is probably as good as it gets, with some kind of accuracy. __________________ WBTA (Water Block Testing Alliance) Nordic Hardware WC 101

11-11-2002, 10:25 AM	#4
abyssling Cooling Neophyte Join Date: Nov 2002 Location: roanoke, va Posts: 9	I need a reliable flowmeter for my test box WC rig It is an asus a7m266-d with the mounting holes drilled out, running dual 1900MPs in serial, currently cooled by MCW372s in a 1/2" setup using a BIX and an Eheim 1250. I want to be able to measure flow accurately to gauge the flow capabilities of blocks and other hardware that I test, as well as try to mod a failsafe shutoff when my flow drops below a certain level. I am aware that I have other bottlenecks in my system currently but I am just trying not to add any more at this point, as I will be testing some true 1/2 setups and do not wish to compromise my data. Price is not a major object for me as long as I can stay under 200 to 300 dollars US I am not too concerned. I need accuracy and ease of readout first and foremost. Also, before you ask why I use a dually for a WC test bed, I have 2 reasons. Number one, I can always unhook 1 proc and run single cpu tests, and still have the option to run comparison testing in dual mode, as well as test various setups in parallel and serial. Contrary to popular belief, serial is not ALWAYS the most efficient, especially in high flow rate setups. I have found that I can somewhat gauge a block's flow capacity by comparing my parallel temps to serial, but obviously it is not extremely accurate. Number two, because its pimp as shiz, and thats what we are all about at pimprig edit Thanks, I'll be sure to check it out! and I appreciate the welcome Bigben, I've always heard great things about you guys

11-11-2002, 11:52 AM	#8
pHaestus Big Player Making Big Money Join Date: Aug 2001 Location: irc.lostgeek.com #procooling.com Posts: 4,782	oops I thought you meant for testing. For show and tell I think the Swissflow unit is best, but pricey and requires import from Switzerland.

11-11-2002, 12:58 PM	#9
nexxo Cooling Savant Join Date: Jul 2002 Location: Brimingham, UK Posts: 385	Several threads exist on this subject. One referred to Dwyer as the place to go and it is indeed recommended! Check these babies out for example: Both have 1/2" connectors and work on 12V. I found a couple of useful ones on RS-Online; a cool-ass flow indicator... (the metal bits are sold seperately and some accomodate 1/2" connections) ... and two flow sensors. This one operates on 5V and senses upto 20 l/min flow (a 300 GPH pump produces 18 l/min). It emits 750 pulses per litre flow; at 18 l/min that is 13500 pulses per minute; similar to a (admittedly very fast) CPU fan. Connections are 3/8". This one has 1/2" connections, runs on anything between 4.5V and 24V, and emits 23 pulses per second at 12 l/min flow. At the aforementioned 300 GPH (18 l/min.) that is 2175 pulses per minute, i.e. similar to a somewhat slow CPU fan. The idea is that when flow stops, so do the pulses, similar to a fan stalling. This should prompt the mobo to perform a shutdown. __________________ "There is a thin line between magic and madness" Last edited by nexxo; 11-11-2002 at 01:10 PM.

11-11-2002, 01:20 PM	#10
pHaestus Big Player Making Big Money Join Date: Aug 2001 Location: irc.lostgeek.com #procooling.com Posts: 4,782	Way too much $$ new. Check www.labx.com or www.ebay.com for used flowmeters. Try and get one that has been calibrated recently. You will be able to find digital flowmeters that output 4-20mA signal. Then buy a an LED display (called an indicator I think) to convert such to flow rates. Should be under $50 for both if you are patient. The dwyer stuff looks nice though. I have a GPI paddle wheel type.

11-11-2002, 02:44 PM	#11
Alchemy Cooling Savant Join Date: Oct 2002 Location: Boston Posts: 238	If you want to go the cheaper route, and you have a bit of space to work with: http://www.omega.com/Green/pdf/FL1340_1440.pdf Rotameters! Alchemy [edit - odds are, you're going to want higher flow rates than that, though]

11-11-2002, 02:59 PM	#12
bigben2k Responsible for 2% of all the posts here. Join Date: May 2002 Location: Texas, U.S.A. Posts: 8,302	More flow rate indeed! At 2L/min max (0.5 gpm), it's quite useless, at least for me (shooting for 4 to 6 gpm). Also, these units are either Alu (bad for my all copper), brass (OK) and Stainless Steel (OK). Personally, I'd rather have an all plastic solution (it's cheaper too!). __________________ WBTA (Water Block Testing Alliance) Nordic Hardware WC 101

11-11-2002, 05:06 PM	#13
nexxo Cooling Savant Join Date: Jul 2002 Location: Brimingham, UK Posts: 385	Some of the aforementioned units are plastic, and reasonably cheap, and will handle 4/6 GPM. Really guys, you can't get better than these. __________________ "There is a thin line between magic and madness"

11-11-2002, 05:23 PM	#14
bigben2k Responsible for 2% of all the posts here. Join Date: May 2002 Location: Texas, U.S.A. Posts: 8,302	Not bad indeed. At $70, where it can be used both as a meter and sensor, that's definitely attractive. __________________ WBTA (Water Block Testing Alliance) Nordic Hardware WC 101

11-11-2002, 06:12 PM	#15
BillA CoolingWorks Tech Guy Formerly "Unregistered" Join Date: Dec 2000 Location: Posts: 2,371.493,106 Posts: 4,440	anyone looked at the pressure drop curves for these things ? ask the mfgrs, they ALL have them you will be quite dismayed, big time I have owned and used every type start by understanding that well over 1/2 of your pump capacity will be 'dropped' across the flowmeter so you cannot use a 'normal' pump and it goes on and on

11-11-2002, 06:54 PM	#17
pHaestus Big Player Making Big Money Join Date: Aug 2001 Location: irc.lostgeek.com #procooling.com Posts: 4,782	I dont see how a paddle wheel type flowmeter could have no pressure drop....

11-11-2002, 11:00 PM	#18
BillA CoolingWorks Tech Guy Formerly "Unregistered" Join Date: Dec 2000 Location: Posts: 2,371.493,106 Posts: 4,440	and equally amazing is this: "Full scale accuracy: +/- 1%" that would take some certified results to convince me with paddle wheels the greater the accuracy, the greater the head loss

11-12-2002, 04:26 AM	#19
BladeRunner Cooling Savant Join Date: Jul 2001 Location: Chesterfield Uk Posts: 459	Hi guys, It's true most commercial flow meters are either far too expensive or restrict the flow down to a tiny hole. They also mostly work by spinning an impeller which makes a noise. As I was only after a flow "monitor" not a flow "meter" I made this auto shutoff system, works really well using this, (cheapish, £13 UK), flow switch shown below, bought from RS in the UK, which uses the same principal as the proximity switch shown in my previous posting in this topic HERE Here's my description of how it works:- Inside the tube it has a small plastic cylinder which sits on the base of the unit positioned in the branch off part. Inside this plastic cylinder is a small magnet. The "cap" at the top of the Y branch has a proximity switch. When the pump is not running the plastic cylinder sits on the base of the unit so the contacts of the proximity switch remain open. When the pump is on the flow pressure makes the cylinder rise up into the branch so causing the proximity switch to close contacts. (there are two versions, 22mm and 15mm), I used the 22mm so it wont cause any overall flow restriction) The output from this is run to a "pulse Generator" unit which is a small cheap & simple electronic circuit I made, (with much help from others), to mimic a fans sensor output, so I could use the original "Smart Doctor" utility with my Water-cooled Asus GeForce 3, (with the GF3's fan removed, smart doctor would pop up all the time saying the fan was dead, and there was no way to disable it). Here is an image of the "pulse gen" It plugs into the CPU fan header on the motherboard. The sensor output from the "pulse gen" is run through the flow switch so when the pump is running the motherboard reads about 3000rpm just as if a fan is plugged into it. If the pump dies or the flow is interrupted by coolant loss, or flow is low etc, the cylinder in the flow switch will drop down and the proximity switch inside will go open circuit cutting the sensor output to the fan header. This will cause the bios to read 0 rpm and instantly shut the PC down if the bios option is set to "shutdown on CPU fan fail". I've since found there is a slight problem with this on my motherboard, (Abit KX7 333R), in that the bios setting for "shutdown when CPU Fan fail" doesn't actually work, (It is enabled). It's also nothing to do with my "pulse gen system" because even with no fan connected it doesn't shutdown. I'm therefore using "Motherboard Monitor" with "Shutdown now" set to force shutdown in 0 seconds on no CPU fan rotation. This works fine and shuts off the PC within a few seconds if the Pump or flow is stopped. A bit of an ass about face way of doing it, but until I can find out why the bios setting doesn't work it will do. The flow switches can be found on the UK RS site, (http://www.rswww.com), by typing this code C257076 into the search feature. You don't have to use a pulse gen, but can just use a fan as long as it can be run from the motherboard CPU fan header. If you are fanless like myself, then here is the circuit diagram for the pulse gen, with components required. Wire trace colours used mainly just to show where they pass each other but are not joined, (they are only joined with a circle). more detail on this in the linked topic at the beginning If you don't need to have a fanless solution the pulse gen unit is not required. It is then very simple to wire up all you need to do is cut one wire and make two wire joins. This very poor sketch should make it clear This will mean when the pump is creating flow the contacts in the flow switch will be closed so the fan will output it's RPM to the motherboard in the conventional way via the flowswitch. If flow stops, or drops too low, pump dies, coolant loss etc the contacts in the flow switch will open so the fans rpm output will be switched off causing the mobo to read zero rpm just as if the fan had stopped working, (although the fan will still be running). The only other things you will need are Motherboard monitor (free), and shutdown now which is free for 2 weeks then costs $19 USD, (make sure you buy it because it doesn't tell you it's stopped working it just pops up a window rather than shutting down). At least you'll have two weeks to get it working and decide if it's what you want. So total cost:- Fan (I'd assume you had one but $5) Flow switch $18 shutdown now $19 total $37 usd without fan, plus a few hours work and maybe some tube, tube clamps and reducers. not much for piece of mind (if anyone does this, motherboard monitor wont allow a setting of 0 seconds to shutoff on CPU fan fail, lowest is 10 seconds but it's quite easy to edit the inf, ask if you need to know how). The beauty is it will power your system off in the correct way if you are not around in event of a failure, so saving your data. If I were running a high watt TEC I'd probably make the system just power off the PSU instantly to be safe. __________________ Zero Fan Zone Last edited by BladeRunner; 06-23-2005 at 04:27 PM.

11-12-2002, 05:04 AM	#21
BladeRunner Cooling Savant Join Date: Jul 2001 Location: Chesterfield Uk Posts: 459	I never got any replies from Abit, (sent it a few times). Didn't really expect a reply I suppose. It does seem to work fine with shutdown now though, I test it a few times each week by shutting the pump off to make sure it works ok. The flow switch after all is just that, a simple make or break set of contacts so you could switch anything with it. It's rated for mains voltage, but I'd rather switch a 12v relay to swich the mains remoltly if I wated to do that. You could of course run the ATX "power up" wire through the flow switch that would be an instant shut down, but the delay on flow start up might cause this to be problamatic. The other option is to use the flow switch to control an adjustable time delay relay, they are pretty easy to make. __________________ Zero Fan Zone

11-12-2002, 05:13 AM	#22
MadDogMe Thermophile Join Date: Aug 2002 Location: Just shut up ;) ... Posts: 1,068	I like the relay~mains idea best as well, turn everything off, pump/TEC/PC the lot!. any chance of a schematic/drawing on how to make a timer curcuit for 'the unwashed' like me? . what chips, parts needed kindof thing. it's the thing every H2o rig should have, especialy if a TEC is used. make a good article. specialy if the sensor is as cheap as £13!, timer included would'nt top £20 probably!...

11-12-2002, 05:36 AM	#23
BladeRunner Cooling Savant Join Date: Jul 2001 Location: Chesterfield Uk Posts: 459	I'll see what I can come up with but it's a bit like the blind leading the blind! I'm no electronics expert, I usually just find a way to do what I need to somehow , Maplin do various 12v delay relay kits btw. Like you say instantly pulling the power to everthing is the best way if you have a TEC. There was a good article about an instant PSU shutoff system in this forum about a year ago that used a temp sensor so it would shut down if the heatsink fell off the CPU. That circuit could be made to work with the flow switch I guess. How have you done yours btw, with the same flow switch as me? __________________ Zero Fan Zone

11-12-2002, 08:15 AM	#24
MadDogMe Thermophile Join Date: Aug 2002 Location: Just shut up ;) ... Posts: 1,068	I'm still trying to get my rig all in the case!. I have to take things step by step due to severly limited funds :shrug:. I'll probly use the same flow sensor because of the cheap cost . is it very restrictive?, has it got a spring inside?, or is it gravity/airtight~pressure that opens the connection?... Thinking about a relay for the 240AC, it'll be hard to switch on because the power is'nt going to be there to activate a timer!. if only it'd only close/open the connection on the relay while the PC is powered. if you know what I mean. a simple push and hold button would work!!, if it shorted/bypassed the connections on the relay while held down (as well as turning the PC on!), it'd have to be held down long enough for the pump to start flowing>sensor~ switch to close> relay to make connection, what do you think?, be easier would'nt it?...

11-12-2002, 08:39 AM	#25
BillA CoolingWorks Tech Guy Formerly "Unregistered" Join Date: Dec 2000 Location: Posts: 2,371.493,106 Posts: 4,440	BladeRunner as usual your work is quite excellent, kudos MDM why not a couple of relays in sereis with a solid state time delay between them ?

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