CW-5000 Chiller overheating

[Michael Mc Laughlin]

Hi Guys,

We have our lasersaur working very well now. The only problem we are having is our Chiller is overheating very quickly. We have the specified CW-5000 which is supposed to be capable of cooling a 200 Watt laser? We are running our 100 Watt laser @100% to cut through MDF. After about 40mins of cutting the Chiller will reach 30 degrees and laser will cut out.

I have the chiller set at factory settings. Are these the best? Could the Chiller be faulty? It takes about 30min to drop the temperature from 30 degrees C to 20 degrees C.

Has anybody had any chilling issues?

Thanks again for your help.

[Jonathan Buford]

If you are venting into an enclosed area or one with a high temperature to start with, the effectiveness of the heat transfer will be lower. I would make sure that the heat output from the chiller has somewhere to go before looking at other issues.

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[Michael Mc Laughlin]

Thank you Jonathon,

We are in Ireland and our building has no heating yet so the room temperature is 12 degrees! The heat definitely has somewhere to go!

Regards,

Michael Mc Laughlin

[Steve Baker]

There is obviously some kind of a problem. We have a CW-5000 and it's
been performing perfectly with 100% power on a 100W laser in a room that's
usually around 24 degC (75 degF). The CW-5000 usually shows a temperature
of around 27 degC while the laser is running.

So if you're sure that the room temperature is that low - then we're left
with only a few options:

1) We know the water is circulating, because the temp on the CW-5000 is
high. If the water wasn't circulating, you'd get a low temp reading and a
water circulation alert.

2) The airflow through the machine might be compromised.
* Check the filters inside the machine - maybe they need cleaning.
* Check that you aren't blocking the slots on the sides of the machine -
you should have at least a foot or two of clearance on each side of the
CW-5000.
* Check that you don't have some other hot equipment (a PC, for example)
exhausting hot air into the CW-5000's inlet vents.

3) The fan might be running too slowly (or not at all).
* Can you hear it running? (It's *REALLY* loud!)
* Does it sound like it's running smoothly?
* Can you feel the airflow through the vents?

4) The thermostat on the machine might be misreading.
* Get a thermometer and stick it down into the water tank...is the water
reservoir really at 30 degrees?

5) Are you sure there is enough water in the chiller? When you first fill
it up, it seems to be full - but when you first start it running, the
water has to fill the hose lines and the inside of the laser tube - so the
level drops considerably. So you need to top it up again after you run
the laser for the first time. Check the water level indicator on the back
of the machine.

That's all I can think of right now...but I'm sure there are other
possibilities!

-- Steve

-- Steve

[j. eric townsend]

On 2/26/14, 10:18 AM, Steve Baker wrote:\rees?

> > 5) Are you sure there is enough water in the chiller? When you first fill

Two things:

1) do you have a water leak? I had some dripping when I first set
things up and the water dripped out under pressure then evaporated
before hitting the summer weather.

2) if it's winter, are you running water or coolant? I'm now running
the same Miller coolant (fancy antifreeze without the radiator leak
stuff) that I run in my tig welder's cooling rig. Is there any reason
to think that water isn't as good as coolant? My studio occasionally
hits ~35F but last year I lost a laser tube in a freakish bout of 5F
weather. When I replaced the tube, I also switched to coolant.



--
J. Eric Townsend, IDSA
design <http://www.allartburns.org>
hacking <http://www.flatline.net>
fabrication <watch this space>

[Michael Mc Laughlin]

Thank you for your help

1) Yes water is flowing.

2)Air flow is ok. All filters are clean, plenty of space around it, no warm machines near it.

3)Fan is running. Air flowing in sides and out back.

4) The water is definitely warm because you can feel it in the return pipe from the Laser. I will try a thermometer later to be precise.

5)Water is definitely full. There are no leaks. The water is distilled water. No coolant.

The only think I can think of is the pump isn't moving the water fast enough? 

What settings are everybody using? I was using default settings. I have now changed it so that the chiller is supposed to keep the water at 15C. Can I set this lower?

Thanks again for your help.

Regards,

Michael Mc Laughlin

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[Steve Baker]

Michael Mc Laughlin wrote:
> Thank you for your help
> 1) Yes water is flowing.
> 2)Air flow is ok. All filters are clean, plenty of space around it, no
> warm
> machines near it.
> 3)Fan is running. Air flowing in sides and out back.
> 4) The water is definitely warm because you can feel it in the return pipe
> from the Laser. I will try a thermometer later to be precise.
> 5)Water is definitely full. There are no leaks. The water is distilled
> water. No coolant.
>
> The only think I can think of is the pump isn't moving the water fast
> enough?

Yes - that's why I think you should measure the temperature in the water
tank.

You'd expect the water coming back from the laser to be warm...the
question is why the water going TO the laser is also warm. Measuring the
temperature in those hoses is tough - but measuring the temperature in the
reservoir should be easy.

> The water is distilled water. No coolant.

Woahh! **BAD** idea!

The instruction book for the chiller clearly says to use antifreeze - and
there are at least four good reasons to do that!!

Distilled water has many problems:

1) Algae will eventually grow in it. No matter how pure the water was at
the outset, if any algal contamination was present inside the chiller,
hoses or laser when you connected it up, you're eventually going to get
green water!

2) Water isn't "wet" enough by itself. The problem is that the surface
tension of pure water is too high and can result in localized hot-spots
when bubbles form and adhere to the surfaces that we're trying to cool.
This is a HUGE problem in car engines - I'm not sure if it's an issue for
laser tubes but I definitely don't want to take that risk!

3) The thermal conductivity of pure water isn't good enough - so heat
doesn't transfer from the laser tube to the water or from the water to the
cooling coils well enough.

4) Pure water can cause corrosion.

5) Water alone may not provide adequate lubrication of pump parts.

Antifreeze reduces surface tension, helps to lubricate pump parts,
prevents corrosion and kills off algae.

Water has a relatively poor thermal conductivity - and anti-freeze doesn't
help that very much. For that reason, I use "water wetter", which
provides the all of the benefits of antifreeze (except that it doesn't
prevent freezing), and it increases thermal conductivity.

There are many brands of water wetter - I've been using this stuff:

http://www.saferacer.com/red-line-oil-racing-water-wetter?gclid=CPPG5O-77LwCFUdk7AodbU4ANg

(I use it in my 1963 Mini Cooper because here in Texas, there is no chance
of a sufficiently hard freeze and with pure water or antifreeze, the car's
pathetic little radiator doesn't work well enough to keep it cool in 38
degC summer days. Switching from antifreeze to water wetter fixed my
overheating problems overnight!)

I doubt that this will fix your immediate problem - but it's definitely
possible, and using distilled water is a very bad idea!

> What settings are everybody using?

Both of my machines are on default settings - and the ambient temperatures
in my workshop are up around 24 degC.

> I was using default settings. I have now changed it so that the chiller
is supposed
> to keep the water at 15C. Can I set this lower?

I doubt this will work. If the chiller's thermostat is set anywhere below
30C and you're getting 30C readings, then there is something wrong. The
chiller is going to turn on the cooling fans any time the inlet
temperature is higher than the set temp - it doesn't matter how much lower
you set it after that point. If the fans are running then I don't see how
there could be a problem with the thermostat.

The thermostat is an on/off device, it doesn't matter how low you set it
so long as it's below the safe operating temperature of the laser tube.

If the chiller fans are running when you're cutting - then either the
temperature read-out is wrong, or there is a problem with inadequate
circulation.

Just a thought...and I'm not sure it matters - but you do have the inlet
and outlet hoses on the correct ends of the laser tube...right? "Inlet"
port of the chiller goes to "outlet" port of laser and vice versa.

Another thought...I'm not 100% sure - but isn't there more than one fan in
this chiller? Maybe one of them is working and the other one isn't?
That would fool you into thinking that there is airflow - when in fact
there isn't ENOUGH airflow.

> Thanks again for your help.

No problem - we're here for you!

-- Steve

[javier buron]

Many thanks Steve! Very informative post, much appreciated! We will try first a 80% distilled water + 20% DowFrost as they recommend on the lasersaur manual, at the moment is 100% distilled water. If that doesn't work we will use your suggested water wetter, do you recommend any specific percentage?

[Steve Baker]

I don't have a specific percentage - I put about a half bottle in there.

-- Steve

javier buron wrote:
>
> Many thanks Steve! Very informative post, much appreciated! We will try
> first a 80% distilled water + 20% DowFrost as they recommend on the
> lasersaur manual, at the moment is 100% distilled water. If that doesn't
> work we will use your suggested water wetter, do you recommend any
> specific
> percentage?
>

> El jueves, 27 de febrero de 2014 14:31:35 UTC, SteveBaker escribió:

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[Michael Mc Laughlin]

Hi Guys,

-I have the chiller running on 20% Propylene Glycol and 80% distilled water. 

-The pipes are definitely connected in the correct way. 

-I checked the temperature in the reservoir. It is correct (i.e when dial reads 26, thermometer reads 26).

- I took off safety guards at back and made sure both fans are working correctly. 

The chiller is still not able to keep laser cool. It can take about 40min for 30C to drop to 20C. Any more suggestions? It has me puzzled!

Regards,

Michael Mc Laughlin

[Adam Plavins]

Could be dusty in the case. Or maybe the refrigerant leaked out.

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[Michael Mc Laughlin]

Thanks Adam

Definitely not dusty.

By the refrigerant do you mean the liquid we add or is there another liquid/gas supposed to be in the chiller? 

Regards,

Michael Mc Laughlin

[Steve Baker]

I didn't think those things had refrigerant...my understanding is that the
CW-5000 is a purely radiative cooler, the CW-5200 is an actual
refrigerator.

I'm betting dust - either in the filters or inside the box itself. There
is a sticker on my CW-5000 saying to clean the filters once a month...and
given how much dust and soot a laser cutter can generate...that's probably
about right.

But as we discussed before - using Glycol severely reduces the ability of
the water to remove heat. The thermal conductivity of water is 0.58 W/mK
versus Propylene Glycol's 0.34 W/mK (you can look those numbers up in
Wikipedia). I'm not sure what a 20/80 mix of glycol and water produces -
but I know that a 50/50 mix is still around 0.34 W/mK - so it's not a
linear function of dilution.

Unless you TRULY believe your workshop will be subject to freezing
temperatures - you should choose something different. (Consider a small
heater placed near to the lasersaur on cold nights!)

The three things that the glycol is doing for you are:

1) Preventing algae growth.
2) Lubrication of pump parts.
3) Lowering the freezing point of your water.

...but Water-wetter can do the first two of those things without reducing
the thermal conductivity and compromising heat transfer capability. Car
nuts have known this for decades:

http://www.redlineoil.co.jp/PDF/WHITEPAP/waterwetter_tech.pdf

I'm not sure that this is your only problem...but it's definitely not
helping!

-- Steve

>> > El jueves, 27 de febrero de 2014 14:31:35 UTC, SteveBaker escribió:

-- Steve

[Michael Mc Laughlin]

Hi guys,

So I can't figure out whats wrong with the Chiller. I am in conversation with Coletech about it. 

I have come across another problem regarding the Chiller. Every time it hits 20 C it gives a click sound. I think this is the pump kicking in? Anyway coinciding with this click at 20 C the laser will stop cutting, loose a few gcode steps and then continue moving around (but not cutting). Its like it gets to 20 C and goes off to do a little dance!  If you reset the laser you can continue to cut perfectly with the temperature above 20 C. Its just the particular point when it changes from 19.9 to 20 C. 

Im assuming that our chiller has a dodgy controller and thus we are having all these problems. What do you think? 

 

Regards,

Michael Mc Laughlin

[Ward Elder]

Could be when the Chiller “Clicks”, it is causing a voltage spike on your mains power and messing up the Lasersaur processor.  Try plugging the Chiller into another outlet somewhere else in your shop.

 

 

Thank you,

 

 

Ward M. Elder

Eldersoft

42 Appleton St.

Winnipeg, MB

R2G1K5

(204) 791-7754   (Cell)

wa...@eldersoft.ca

[Steve Baker]

So - when it hits some magic temperature, the fans presumably kick in (or
should kick in and aren't?) - and that's causing the glitch.

I guess there are two possibilities

1) The signal back to the Arduino that says that the chiller is OK is
momentarily saying "NOT OK!"

2) There is enough noise being emitted down the power lines to glitch the
lasersaur electronics.

There is a very easy way to test this: Temporarily disconnect the chiller
warning signal and short out the pins on the controller board. If this
"fixes" the problem - then you know it's (1) and not (2). Obviously you
shouldn't leave it like that...but at least you know what to look at.

If it's (2) - then you can try a couple of things - one is to plug the
chiller into another outlet - preferably on another circuit in the
building. Another is to buy a ferrite power cord (or a ferrite block to
bolt around your existing power cord. These things do deep magic in
getting rid of power glitches. Another alternative would be to get a
power supply smoother for the lasersaur. I have that just because I
don't like the idea of glitches from my refrigerator or A/C unit tripping
out the lasersaur...so that' probably a good idea anyway.

If it's (1) - then I'm not sure what to do. When the alarm circuit on the
chiller REALLY trips, it makes a noise - so if you're in the room with the
lasersaur (as you should be because you need to watch out for fires and
other nastinesses!) - then you'll hear the alarm and you'll have time to
hit the big red ESTOP button before your laser tube gets damaged. So I
suppose you could just disconnect the chiller warning signal permanently.

You could try putting a hefty capacitor in the line from the chiller to
the controller board - that would smooth out any glitches....it's a very
low frequency signal, and the precise timing of it doesn't matter - so you
could put a fairly large capacitor on there.

Obviously that's a bad thing to do if you can avoid it...and it would be
really good to know why this is happening because it could easily be a
symptom of something much worse! But coletech are not very good at
customer satisfaction and after-sales service...so getting them to fix it
may be prohibitively difficult...although you should of course try!

-- Steve


Michael Mc Laughlin wrote:

>> escribió:

-- Steve

[Ludo Verbiest]

Hello Jon,

2 weeks ago, I also bought a chiller,  a CW 5200 in the beginning, everything seemed to be OK

Today, however, after I have run a few more intensive program ´ s, I had the same problem as you.

So I also checked everything,

 - electrical connection                               OK

 - temperature sensor                                OK

 - the fans                                                   OK 

 - pump                                                       OK

 - water level                                               OK

 - settings                                                    OK                                   

 - Obstructions                                            None

 - connection water flow water pipes          OK 

 - water flow direction                                 OK

So after all this intensive exploration work, I first had to  scratch my hair and drink a cup of tea to cool down, because in the meantime not only the chiller was overheated

BUT SOMETIMES THE PROBLEM JUST LIKE A LITTLE DEVIL HIDES IN A DARK CORNER

After my relaxing Cup of tea and a little cursing I decided to open the chiller case,

and what I saw there you can see in the attached picture ´ s

I am now talking to the supplier to resolve te problem, but it definitely shows a production error and of course  I expect a new device from the supplier

Perhaps you also have to look inside your device.

I hope this can help you

Ludo

Op woensdag 26 februari 2014 12:23:02 UTC+1 schreef Michael Mc Laughlin:

[Stefan Hechenberger]

This sucks. Thanks for posting details. This is always helpful to us
Lasersaur builders.

---
Stefan Hechenberger
work: http://nortd.com
project: http://lasersaur.com
twitter: @stefanix
instagram: @stefavon

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