[kb0nly]

Great thanks I ordered from the eBay link you posted.

Welcome!

By the looks of the tracking i should have my second unit tomorrow. It has a broken connector for the water line and keeps going into Watchdog, should be an interesting troubleshooting challenge. From what i can tell with my current one the watchdog alarm usually goes off if the pump doesnt come up to full speed or if the cooling fans aren't running. Hoping for something simple like a bad fan or maybe a pump power supply issue, who knows. But it will be a fun challenge nonetheless!

[jfong]

Received the plugs today and made a short loop back. The chiller works just fine all the way down to 4C, the lowest setting. The tubing get cold. This is great!

[kb0nly]

Nice! I just got my second unit today to start repairing it.

Sent from my XT1254 using Tapatalk

[kb0nly]

Ok, the second unit is now running and testing it. Seems to be working fine so far provided it reaches the set temp and maintains it, so far though so good!

The unit was described as showing Watchdog Alarm on the display after a few minutes. I turned it on the first thing i heard was a horrendous rattling noise and the rear fan for the dehumidifier was running, my other unit that fan never even run. So i shut it off opened it up and unplugged the power to the dehumidifier board and then turned it back on and was immediately greeted with Check Fluid! Success! The air pump in this one for the dehumidifier is shot and rattling and causing the Watchdog to set, so removing power to that board and hence the pump and fan shut it up. Dumped in some coolant and the Check Fluid message went away, relays clicked, and it started the water pump which is perfectly silent and smooth. This one has a broken water output fitting though, so for now i have the hose fitting pushed into it and a clamp holding it in until the replacement part gets here that i just ordered after making sure it was worth spending money on it. The female socket fitting PLCD16006 is around $15-$20 online, its a 1/4" flow fitting to 3/8" barb for the hose coming off the pump.

It seems the failure point on these units is the dehumidifier section, which isn't needed for purely water chilling operation. Since i have to take apart the hoses on this one to replace the fitting i am going to strip the dehumidifier section out and put some plugs in the fitting holes, the T252-P seems to come in that config from the factory as well, i see a few on ebay with black plugs where the air fittings would be for the dehumidifier section. So they obviously made them with or without that option which is why it works by just removing power to it and leaving it.

So far its down to about 6C and still dropping in temp, seems to be working fine!

[jfong]

On my unit the back fan operates and I could feel air coming out of the outlet. I couldn't get out of the initial error until I unplug the H board. Good that your second works.

[kb0nly]

The back fan is powered off the Dehumidifier board, so once thats unplugged it and the air pump don't run, which is a good power savings to on the power supply because then the back TEC in that unit isn't powered. I pulled the air pump, air fittings, and the entire dehumidifier assembly out of my second one. Its just a TEC with the air pump blowing over the cold side to pull out condensation, which gets drawn into a little wick that pulls it down to a little drip tray at the bottom of the hot side of the heatsink, which the fan is blowing in onto and cools the heatsink as well as evaporates the condensate sitting in the little tray. Pretty neat little unit. I think i'm gonna save mine and attach it to a foam cooler for a jerry rigged TEC powered cooler... LOL

Now that i have that all out and investigated i just have to wait for the new water outlet fitting to arrive to repair this unit completely and its done. I did think about putting a fan in the back to move air around the power supply inside, they don't seem to provide any cooling for it whatsoever, and the dehumidifier unit when running actually adds heat to the inside of the units back half because the rear fan pulls inward over the hot heatsink of that unit. Seems like an odd setup but i understand why they did it for the condensate.

[KeeWay]

i just got my unit with a bad dryer section and thanks to the advice here from kb0nly i unplugged it and it seems to now cool and heat with no problems.

so i have one question, when you turn off your unit does your set point save or do you have to keep resetting it every time you turn it back on? mine does not save but i want to double check with everyone.

[kb0nly]

i just got my unit with a bad dryer section and thanks to the advice here from kb0nly i unplugged it and it seems to now cool and heat with no problems.

so i have one question, when you turn off your unit does your set point save or do you have to keep resetting it every time you turn it back on? mine does not save but i want to double check with everyone.

Great to hear that! I have two of these units now and love them!

It doesn't appear to save the set point when completely shut off, i checked over the control boards there doesn't appear to be any battery or super cap backup for what the unit is set to when shut off. What i do is if i'm doing some on and off cutting during the day i just press the start/stop button and leave it with the screen saying Press Start, thats kind of a standby mode basically that shuts off the pump and the TEC's and it just keeps power to the controller. If i'm done for the day then i just flip off the power switch, but i have to set the temp again the next day or next use. Its kind of a slight annoyance but considering the price of the unit its one i can live with!

It uses very little power according to my kill-a-watt meter when sitting in standby so you could leave it on for days without much worry, but i tend to use the laser a full day or two and then not for 3-4 days so i just shut it completely off. When i get ready to cut i set the temp down and get it running and let it cool down for 20-30 minutes before i start using the laser.

I think the way these were originally used they probably were on most of the time or in standby, so they probably didn't turn them on and off a lot. The power switch on my units is really crisp and quite new feeling in operation, they definitely don't seem to have very many cycles on them.

One work around i have been playing with is that apparently you can set the temp and gradient via the serial connection on the side of the unit, so i have been working on exploring that. Then i could boot up the computer turn on the laser and the chiller and set the temp from the computer instead of having to hit the temp down a dozen or more times... LOL

[KeeWay]

Great to hear that! I have two of these units now and love them!

It doesn't appear to save the set point when completely shut off, i checked over the control boards there doesn't appear to be any battery or super cap backup for what the unit is set to when shut off. What i do is if i'm doing some on and off cutting during the day i just press the start/stop button and leave it with the screen saying Press Start, thats kind of a standby mode basically that shuts off the pump and the TEC's and it just keeps power to the controller. If i'm done for the day then i just flip off the power switch, but i have to set the temp again the next day or next use. Its kind of a slight annoyance but considering the price of the unit its one i can live with!

It uses very little power according to my kill-a-watt meter when sitting in standby so you could leave it on for days without much worry, but i tend to use the laser a full day or two and then not for 3-4 days so i just shut it completely off. When i get ready to cut i set the temp down and get it running and let it cool down for 20-30 minutes before i start using the laser.

I think the way these were originally used they probably were on most of the time or in standby, so they probably didn't turn them on and off a lot. The power switch on my units is really crisp and quite new feeling in operation, they definitely don't seem to have very many cycles on them.

One work around i have been playing with is that apparently you can set the temp and gradient via the serial connection on the side of the unit, so i have been working on exploring that. Then i could boot up the computer turn on the laser and the chiller and set the temp from the computer instead of having to hit the temp down a dozen or more times... LOL

Ok good to know it is just not my unit. i guess for $50 i can live with setting this every time i turn it on or like you said just leave it on with the pump off.

the serial control sounds kinda cool but my laser is only network connected right now.

thanks again for this post especially going into the summer months my current radiator/fan method would not do much in the way of cooling.

[kb0nly]

Your welcome! Glad i could help out.

Being on the electronics side of the guru bench i will keep looking for a way to deal with the temp setting but i just need time to do it, and time is harder to come by then the knowledge to do it for me! I do see that looking on the controller board there is the possibility for pulling a firmware chip, it reports its firmware version when turned on, i wonder if i can edit the firmware to have a default temp of whatever my liking, that would be neat. Just turn the power on and it comes on at the temp i set internally. I can't imagine it would be too hard from a editing perspective, 30 degrees is its highest setting and thats what it defaults to, so if i set its highest setting to whatever i want in the firmware then by rights it should always turn on at that temp. Like i said, just need the time to monkey with it!