Most lasers include a basic external water pump for cooling the laser. With this configuration, you place the pump in a bucket of water with ice packs to keep your laser cool. The problem with this is you don't know what the temperature is, and you have to constantly replace the ice packs. Laser tube life is shortened by excessive heat and overdriving the tube, so a chiller is one way to help prolong the life of your laser. It's a large cost upfront, but it should save you money and downtime in the long-run by extending the life of your tube. For this reason, a chiller should be purchased at the same time you purchase the laser. Here is a good article on chillers: Laser Report: The Value of Water Chillers. Scroll down to read more about chiller selection and installation.
Click on a Retailer Below to Purchase an S&A Chiller
S&A, a manufacturer of chillers, is considered to be the gold-standard for chillers. In fact, their chillers are so popular, that the Chinese are starting to copy Chinese product! While there are clones out there, the biggest advantage to spending a couple hundred dollars more on an S&A chiller is that they have a 2-year warranty, they have service parts available, they offer technical support, and there is a large support group and programming videos for them.
Three popular models of the S&A 110V chillers are the: CW-5000, CW-5200, and CW5202. The CW-5000 is suitable for 100W and below, the CW-5200 is suitable for 100W-180W, and the CW-5202 is designed for use with two lasers up to 100W. You can always start with a larger chiller if you think you might upgrade your laser in the future or are using it outdoors in excessive heat. If you have been doing your research, you're probably wondering why the CW-3000 is not on the list. While the CW-3000 looks like a chiller, it is in fact not a chiller. It is simply a radiator with a fan and the best it can do is maintain room temperature and not the typical 17-19 degrees Celsius required for a laser tube (remember, heat equals a shorter service life). Often people who purchase these end up returning or selling them because they don't meet their needs.
A lot of chillers look similar, so you might think you are buying a true S&A, when you are not. Click on the following guide for more information: How to Identify a Genuine S&A Chiller.
In Nov 2020, OMTech released a chiller line. So far they have proven to be very reliable. The CW-5000 is suitable for 100W and below, the CW-5200 is suitable for 100W-180W, and the CW-5202 is designed for use with two lasers up to 100W. Also, the programming is nearly identical to S&A, so much that one would have to wonder if these chillers are not being manufactured by S&A. If was purchasing a laser directly from OMTech, I would not hesitate at picking one of these chillers up at the same time.
While I am not a fan of placing a laser in subzero temps because it has a glass tube filled with water, I do recognize that sometimes there is no other option. In February 2021, LightObject released a series of chillers with a built-in heater. The advantage of a built-in heater is that the system remains a closed-loop, which, in theory, should help reduce algae. The Q600s is suitable for 80W and below, the Q800s is suitable for 80W-130W, and the Q1600s is designed for 130W-180W. Since these are new to the market, little is known about their reliability or how well the manufacturer honors their warranty.
Note: In the Facebook Groups, I have seen a large number of DOA failures with the S&A and OMTech chiller clones. Not all the clones will fail, and there are people out there who have not had issues, but you should ask yourself if you want to risk the aggravation and downtime that goes along with replacing a chiller. They ship in large heavy boxes in excess of 50LBs, so it is a hassle to get them shipped. In many cases you won't even be able to ship them to get them repaired, because the seller will not honor the warranty and you will not be able to locate the manufacturer. Often the machines don't even have a warranty, so you are on your own after 30 days. Repairing it yourself will also be difficult because there is usually no service parts availability. Lastly, you may have difficulty finding programming information. Do yourself a favor and spend the extra $200, more or less, to buy a quality chiller, and consider it like an insurance policy to avoid a potential headache down the road.
S&A, OMTech, and Preenex Chiller Installation Instructions:
Follow the steps below to install a CW-5000, CW-5200, or CW-5202 chiller.
a. Connect Hoses. Locate the silicone hoses included with the laser. Connect the OUTPUT from the laser to the INPUT on the chiller, and the INPUT from the laser to the OUTPUT on the chiller. Secure the hoses with zip ties.
Note: If your chiller is a model CW-5202, then you will have two sets of inputs and outputs. If you only have one laser, you will need to connect a bypass tube from the INLET B to OUTLET B.
This is a video showing the unboxing and installation: Water Chiller Installation
b. Program the Chiller. Program the chiller for 18 degrees C. This is a great video on programming the chiller: Chiller Programming. For those who don't like to watch videos, you can follow these steps:
Fill the chiller with approximately 1.75 gallons of DISTILLED water. Do not overfill!
With the power OFF, Hold both the UP and DOWN, and turn the power ON (this will reset the chiller to factory defaults).
Note: Each arrow button has a left and right position, so be sure you're pushing on the arrow, and not on the center of the button.
The letters Re will appear.
Press UP and SET until 0 appears.
Change to 0 to 8 and press SET (8 is the default password).
Scroll to F3 and press SET. Change from 1 to 0 (this will change mode from Intelligent to Constant) and press SET.
Scroll to F9 and press SET. Change the minimum temperature to 15 degrees and press SET.
Scroll to F0 and press SET. Change the constant temperature to 18 degrees and press SET.
Press RST to save the changes. Your chiller is programmed.
Immediately check for leaks inside and out.
c. Power on the Chiller and Check for Leaks. Push the black rocker switch to the "I" position, and check for leaks at the chiller, at the external connections on the laser, and inside the laser. Believe it or not, it is not uncommon to find leaks due to loose and/or missing clamps from the factory.
d. Remove Bubbles from the Laser Tube. Open the rear door where the laser tube is located and see if there are any bubbles inside the glass laser tube. If there are, try to remove them by squeezing the silicone water lines while the chiller is running (this is the best method). If you still have bubbles, you can try and gently tilt the laser to get them out. Lastly, you can loosen and gentle rotate the laser tube (be sure to note the position of the tube first).
Note: Water usually enters the tube on the left hand side and exits out the right. If you have bubbles and still cannot get them out, check that your tube is oriented correctly. Often there is a sticked that says, "this side up," but I have seen instances where the sticker has been applied incorrectly. Generally, the water line on the right will point upward, or at least slightly upward, which makes it easier for the bubbles to escape.
e. Connect Redundant Flow Sensor (optional). This step is optional, but it is recommended. Typically a pressure (or flow) sensor is wired to the Ruida which will prevent the unit from running without water flow. However, you may optionally connect the aviation connector, included with the chiller, to the alarm output on the chiller to the laser tube power supply for redundancy. The power supply will not let the laser fire is water isn't flowing. On the back of the aviation connector there will be three pins, solder a 22 gauge wire to pins 1 and 3. Then take the wire from pin 1 and connect it to the G (Ground) terminal on the laser power supply, and take the wire from pin 3 and connect to the WP or P (Water Protection Switch) terminal on the laser power supply (this is usually a blue or black box, it is not the white controller). Note: If there is a jumper wire from G to WP/P, you will need to remove it.
This is a great article, with diagrams, on connecting the optional flow sensor: Chiller Alarm Connections.
f. Installation is Complete.
Tip: If you're concerned about water leaks on your floor, consider purchasing one or two of the below water alarms.
Required Components and Tools to Connect the Redundant Flow Sensor:
Optional Components for the Chiller:
Some machines ship with wire ties on the hoses instead of hose clamps. Spring Hose Clamps hold better than zip ties and are less likely to damage the soft silicone hoses. Plus they don't require any guesswork on tightness like worm-drive clamps. The 11mm and 12mm clamps in the below kit are the most popular sizes. Measure the OD of your hose to determine which clamp size to use. Note: The Spring Hose Clamps are not be used where the tubing connects to the glass laser tube.
Notes About Algae:
Over time, an algae-like organism will start to appear in your water and your tube if the chiller water is not frequently changed, this is not desirable. To prevent this, S&A recommends changing the water every 3-6 months (your environment may differ). There is lot of discussion online about using additives to prolong the quality of the chiller water. However, there does not seem to be a consensus as to which method is best. I reached out to S&A for their opinion, and they do NOT recommend using anything other than distilled water. For completeness, I have included popular practices that people are using online, but are NOT recommended: 1.) Antimicrobial Silver Coil - because it may jam the pump rotor because its small size, 2.) Bleach - because it is corrosive; 3.) Algae Control, including Tetra Algae Control - not recommended, no specific reason given. If I had to have an additive, Tetra Algae Control seems to be the lesser of the evils.
Here is a good article about Laser Water Coolants and Additives.
Notes About Freezing Temperatures:
A popular question is about the use of RV anti-freeze, propylene glycol, or Dowfrost to keep the water and the tube from freezing. I contacted S&A support about the use of antifreeze and they recommend a ratio of no more than 30% coolant (I have been finding most people use 50/50 in the field). They also said to be sure to drain it as soon as the season is over. These coolants raise electrical conductivity, cause corrosion, reduce cooling ability, and increase algae growth, so it's possible that they may cause damage over time. The safest method for keeping a tube from freezing seems to be the use of an aquarium heater with a chiller (or a chiller with a built-in heater, such as the LightObject models above). I could not find any long-term, real world use cases to determine how well either of these methods protect a tube from freezing or if they cause long-term damage or performance issues, so proceed with caution. Considering the amount you have invested in the machine, and the cost and aggravation of replacing a tube, chiller, etc. I would try to place the laser in a conditioned environment to avoid the risk altogether. If your only option is to place it in a sub-zero environment, do NOT count on RV antifreeze alone to keep your tube from cracking (I have seen reports of tubes with RV antifreeze cracking at -10 degrees F). Therefore, I would suggest a combination of anti-freeze, a heater, and a running chiller to help reduce (not eliminate) the risk.
Below is additional information from OMTech about freezing temps (link to original article: www.facebook.com/groups/omtechlaserusergroup/permalink/594155985104816):
"Allowing your laser tube’s cooling water to fall below 50°F (10°C) will hinder your laser’s performance and can lead to permanent damages. If the cooling water freezes, it will expand and cause the tube to burst or fracture. Be aware that these temperature damages are not covered by OMTech’s laser tube warranty.
Here is a good article about Laser Water Coolants and Additives.