Low coolant alarm at Maplins

[stilldesperate]

Hi all,
Had a very helpful PM from Haydn (thanks Haydn), and am going to put what I've found into words and pictures (hopefully) when I get home this eve.

I don't want this to be a unit to hinder Haydns' sales, everyone says it is a very good product, and he's been good enough to contact me already.

If I tell you why I want a cheap unit, maybe it'll make sense. I've jut bought a Bongo (my second), but there's a hole in the radiator. The rad guy says he can tell that either the head is cracked, or the gasket's weak. I'm putting a second hand rad on, and want to run it for a week or two, to see if he's right (before spending mega bucks on stripping down). I don't want to get caught out, and came up with this as a"quick 'n' dirty temporary solution.

If you want to permanently monitor your water, I'd give Haydn a call....... If you want to give this a go, (in the spirit of the forum), I'm happy to share........

SD

[Manny]

one way of reducing the average current through the water to reduce electrolysis would be to sample with pulses of say a few milliseconds on and several seconds off. Of course that would make the circuit slightly more complicated and expensive.
I bought Haydn's alarm even though I also like tinkering with electronics, it can take a long time to experiment with these things to get it right. So why re-invent when there's a proven system at a reasonable price.

Manny

[haydn callow]

If I tell you why I want a cheap unit, maybe it'll make sense. I've jut bought a Bongo (my second), but there's a hole in the radiator. The rad guy says he can tell that either the head is cracked, or the gasket's weak. I'm putting a second hand rad on, and want to run it for a week or two, to see if he's right (before spending mega bucks on stripping down). I don't want to get caught out, and came up with this as a"quick 'n' dirty temporary solution

The problem with what you are thinking is that "if" your head gasket or head goes it is unlikely to result in coolant loss..The coolant will probably rise in the first instance and be ejected out of the pressure cap. To detect this extend your overflow tube and point it up the windscreen..or...as a Aussie farmer does with his fleet of 4x4's ...extend it so it is just above the drivers feet....that stops them super quick. The coolant alarm was needed when the rad was holed in the first place ...all this wouldn't have happened. (hindsight is a wonderful thing even if it can be annoying)

[lizard]

Seems lovely and cheap but I will stick to the brilliant Haydn mk3 alarm, its the dogs bollocks for me.

I thought about trying these, but the fur would get in the way.

[missfixit70]

Seems lovely and cheap but I will stick to the brilliant Haydn mk3 alarm, its the dogs bollocks for me.

I thought about trying these, but the fur would get in the way.

Just PMSL

[stilldesperate]

The problem with what you are thinking is that "if" your head gasket or head goes it is unlikely to result in coolant loss..The coolant will probably rise in the first instance and be ejected out of the pressure cap. To detect this extend your overflow tube and point it up the windscreen..or...as a Aussie farmer does with his fleet of 4x4's ...extend it so it is just above the drivers feet....that stops them super quick. The coolant alarm was needed when the rad was holed in the first place ...all this wouldn't have happened. (hindsight is a wonderful thing even if it can be annoying)[/quote]

Good point, Haydn. I havn't even driven the thing yet, I've bought it like this...

Posted the modded circuit on here:

http://s625.photobucket.com/albums/tt34 ... sensor.jpg

[Hotpot]

Seems lovely and cheap but I will stick to the brilliant Haydn mk3 alarm, its the dogs bollocks for me.

I thought about trying these, but the fur would get in the way.

Just PMSL

Me too

[missfixit70]

The problem with what you are thinking is that "if" your head gasket or head goes it is unlikely to result in coolant loss..The coolant will probably rise in the first instance and be ejected out of the pressure cap. To detect this extend your overflow tube and point it up the windscreen..or...as a Aussie farmer does with his fleet of 4x4's ...extend it so it is just above the drivers feet....that stops them super quick. The coolant alarm was needed when the rad was holed in the first place ...all this wouldn't have happened. (hindsight is a wonderful thing even if it can be annoying)

Good point, Haydn. I havn't even driven the thing yet, I've bought it like this...

Posted the modded circuit on here:

http://s625.photobucket.com/albums/tt34 ... sensor.jpg[/quote]

Modify it to act as a hi level or overflow alarm?

[scanner]

Seems lovely and cheap but I will stick to the brilliant Haydn mk3 alarm, its the dogs bollocks for me.

I thought about trying these, but the fur would get in the way.

It's the howling noise when you first turn the key that makes my hair stand on end.

[helen&tony]

Hi
A water alarm.....just what I've been looking for!!!!!.....I'll catch 'im indoors when he's had a few beers and pees outside the back door
Cheers
Helen

[Trouble at t'Mill]

Missfixit, the top (original) circuit should work fine as a high-level alarm.

To the best of my knowledge, the modified circuit below won't work as it stands without major alteration (increases) to the resistor values. In any case, a 10k resistor from the 12V rail would supply around 1.2mA, which is 1,200uA, to the coolant which I understand from posts on here could cause 'coating' problems on the probes.

[haydn callow]

Our Top Man in the EnginSaver research labortories over in Oz has been taking some interest in this topic and has provided the following info in a effort to save some Bongo Rads. Poor chap has been working whilst we have all been asleep...

Photo 1 is a peice of wire coated with the same solder as is used in radiators.
Photo 2 is the same peice of wire after having been used as a probe for five hours with a 10k resistor at 12.3 volts as in the circuit in the post
Photo 3 speaks for itself
Photo 4 shows the coolant..the bits are bits of probe
On test it actually supplied 1.13 milliamps
This rapidly decreases as the solder is damaged and the resistance rises as the probe coats.
This will of course cause the alarm to go off.
The inside of a bongo coolant tank is quite conductive, so using this device as a hi-level alarm is not a good idea either.
That is a lot of electricity

All this has been info has been aquired over the years..somtimes as a result of bad experiences

[dandywarhol]

Good research Haydn - this of course is why these devices cost more than only a few quid - development takes a lot of time...................................