PPM-2A controller way out of calibration

[ghdaddy]

I just picked up a used co2 setup...tank, regulator and cap ppm-2a co2 controller. Unfortunately the controller seems to be way out of calibration. It reads about 1480 in a 100 Sq ft room. After I'm in there for an hour it's close to 2400 or even 2500. I took it outside and left it there for 30 minutes...still 1000. Obviously incorrect readings.

CAP went out of business and Hydrofarm bought select items from their line. The PPM-2A was not one of them. I found the instructions manual online. It states to "reset" it, just unplug for 20 second set and plug back in. I found another place that said that if the controller was on and tank ran dry for extended period...I need to plug in and it will take a few hours to a few days to recalibrate itself. We are on day 4 and numbers seem to be the same. They say if that doesn't work to send it in to be recalibrated, that company doesn't exist. Hydrofarm was zero help.

Does anyone know own how to fix this problem? Is it a part that needs to be replaced? If so, hydrofarm was no help tracking it down. Or am I just shit outta luck?

 

[hvac guy]

Did you clean the filter, when it's really dusty and clogged, it affects readings?

 

[ghdaddy]

I know nothing of this unit. Do you know where to look or what to do to clean? It's not obvious to me what to do without opening up the unit itself. The manufacturer doesn't want you in there...theres that special tape on seals. I assume voids warranty. Not that that's a big deal.

 

[hvac guy]

Is there a plastic cover vented with a small screen, it should pop off and you can remove the filter screen. Should be on the bottom of the controller. All the other CO2 controllers I've installed have that feature.

 

[Limeygreen]

Is there a calibration button to use? If so you might need a 0 and a 2000 ppm gas to calibrate it.

 

[ghdaddy]

 

[ghdaddy]

I believe the 3rd pic is of the co2 sensor inside the controller. Anyone? If so, what can I do with this information? Is that likely the culprit?

 

[Bobby Boucher]

My CAP did the same thing for months. CAP, if you weren't aware, went out of business. I would avoid their stuff. Their lighting controllers are a fire hazard, and I wouldn't be surprised if the rest of it was fire prone either. When I came around asking about this same thing several years ago, I was told there was a break-in period. My readings were about exactly the same as yours. 1100-2500. It took at least a couple months before my ambient starting showing ~3-400.

If you know how much co2 your regulator puts out, and how many cubic feet are in your space, you should easily be able to calculate how long your tank would have to run in order to reach your ideal ppm, and then compare your ppm reading with your "actual" ppm and adjust accordingly. After I did my little text, I found that the actual ppm's were very close to HALF of the reading. I set my controller to 2000 ppm until I noticed the ambient ppms had gone to believable levels.

 

[ghdaddy]

My CAP did the same thing for months. CAP, if you weren't aware, went out of business. I would avoid their stuff. Their lighting controllers are a fire hazard, and I wouldn't be surprised if the rest of it was fire prone either. When I came around asking about this same thing several years ago, I was told there was a break-in period. My readings were about exactly the same as yours. 1100-2500. It took at least a couple months before my ambient starting showing .

Wow. You had yours plugged in for months looking at bad readings? Thats patience. That would be a daily reminder to me about my bad purchase. I would have junked it after a week I think. Did you actually have it hooked up to regulator and co2 source during that period or just have it plugged in waiting for it to stabilize?

 

[Bobby Boucher]

yeah, if the controller hadn't been $700 I would have chucked it out the window. I already threw away my mlc-4x before it got the chance to fail on me. Now it just functions in my grow as a very pricey thermostat and co2 monitor, not a regulator.

During the break in period, I had everything plugged in and running to a 4x lp propane burner. Cycled just as expected at 2k ppm readout to 1k actual.

 

[ghdaddy]

Did you have the ppm-2a set to double actual goal? Or did you have a timer control burner during break in periid?

 

[hvac guy]

The CO2 sensor module may be replaceable, find a part # if there's one on the CO2 PCB, and Google it.

 

[Bobby Boucher]

Double the actual goal. Once I noticed my ambient ppms drop to 900, I set to 1800, when it came to 800, I set to 1600 and so forth until my readouts made sense. Took awhile.

 

[hvac guy]

Here is the replacement part;

http://www.apollo-sensors.com/s04/apollo-sensors/cpxx/20090401/6942275.html


Send them an email and ask if they have a specific way to recalibrate or if you can send them the part and have it tested or purchase a replacement.

 

[Bobby Boucher]

I'll add that once I figured out how long it should take to fill my room (there are calculators online) I regularly monitored my controller with a timer to make sure I wasn't actually hitting double my mark. Timing always seemed right.

 

[ghdaddy]

Hvac guy..thanks. at first glance my sensor has 1 more letter in its model number than the one listed in that link, but 1 of them probably works just fine. I think I'll try to contact them and ask. In the mean time I'll attempt the Mr Boucher method. I just hate to throw it away