Low cost sniffer

[Glacier991]

I have long been advocating folks to invest in a gauge set, and at the same time railing against the cheap gauges that come with recharge kits.... misleading folks into thinking AC pressures are like tire pressures, which is NOT true... And now you can buy a gauge set on sale at Harbor Freight for about $40-. No more excuses.

I have a couple sniffers.... one barely works, one works decently but is getting older. Oh, a sniffer ? an electronic device capable of detecting minute quantities of Halogens....

I have a UV dye detector... you add UV flourescing dye to a fluid and in a darkened area use UV light to see where it is leaking.

I have to admit I have not had great luck using the UV setup on 134 Refrigerant systems. My theory is that the molecules of 134 are so small maybe the dye gets left behind or something.... regardless, I'm not a huge fan of UV in AC systems as a great leak detection tool.

I was pleasantly surprised when I saw that HF had started carrying a halogen leak detector for $99.... even more when it was on sale for $69. I decided to pick one up and try it out for you all....

Well, I did that and checked it out by simulating a leak and comparing it against my other tester.

Well. I was very pleasantly surprised. It is every bit as sensitive, if in fact not a little more so. So, now I want you to get a gauge set, and if you have a leak problem, BUY this sniffer!!!

I'll update this with some pics later.

 

[BrooklynBay]

Which model did you buy? I know that they were selling them for a while. The sensitive electronic sniffers use the "ionic wind effect". This is used to increase the normal sensitivity of regular sensors to push whatever comes in its path closer to the sensor. It sends a high voltage stream of electricity across a spark gap to trap the gas which goes into it. They made propane test kits before these sophisticated gadgets existed. The color of the propane flame would change when it came into contact with freon gas.

 

[Glacier991]

Item 92514 is HF's number. I have used the old propane models... they did not work very well compared to the sniffers and required a good eye and proper lighting conditions.

 

[BrooklynBay]

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92514
http://www.harborfreight.com/manuals/92000-92999/92514.pdf

 

[Nocturnall]

Now if only I could find a cheap pump I would be finally able to fix my a/c so I'm not dyin in the AZ heat any more.

 

[nolimitssjca]

Glacier, you find the coolest stuff!

I confess I tell people to not be afraid to charge their A/C and that if they can check a tire pressure, they can check their A/C pressure. Of course trroubleshooting is a whole different animal.

 

[Glacier991]

Be careful drawing the analogy between tire pressure and AC pressure, they are WAY different animals and behave MUCH differently.

 

[BrooklynBay]

Now if only I could find a cheap pump I would be finally able to fix my a/c so I'm not dying in the AZ heat any more.

I made a vacuum pump out of an old compressor from a window style A/C unit. Another option for you is to get a small 12 volt compressor such as an MV-50, MF-1050, or the Harbor Freight version, and connect a hose onto the inlet line where the filter is normally connected. If you have a shop compressor, you could get one of those air powered vacs like the type Harbor Freight sells. They sell one for R-12, and another one for R-134a. Check # 50 in my list of useful threads for information on these compressors: http://www.explorerforum.com/forums/showpost.php?p=1648737&postcount=5

 

[Brock94]

I bought a very old TIF model on eBay for about $15 that came with a brand new sensor tip. It seems to work pretty well, though from all the negative comments I've seen from A/C techs, I get the feeling these things work better at home than in a shop environment. I've never had trouble finding a leak with this thing and it's great to go over a system after you had it apart or after you worked on other things to see if you disturbed an O-ring somewhere and caused a slow leak.

I once fiddled with the low pressure sensor on the a/c system in the process of fixing something else. I did a quick check with the sniffer and found I had caused a slow leak. I swapped in a new o-ring and it saved me a hot trip and the cost of a refrigerant charge.

Just remember that refrigerant is heavier than air, so it tends to go down from the leak point (not sure how it supposedly get up to the ozone layer, but that's a whole other discussion).

 

[Brock94]

I made a vacuum pump out of an old compressor from a window style A/C unit. Another option for you is to get a small 12 volt compressor such as an MV-50, MF-1050, or the Harbor Freight version, and connect a hose onto the inlet line where the filter is normally connected. If you have a shop compressor, you could get one of those air powered vacs like the type Harbor Freight sells. They sell one for R-12, and another one for R-134a. Check # 50 in my list of useful threads for information on these compressors: http://www.explorerforum.com/forums/showpost.php?p=1648737&postcount=5

Just curious-- how much vacuum can you get with the window a/c compressor and from a 12 volt unit? Is it enough?

 

[BrooklynBay]

I haven't tried the 12 volt compressor yet, but the A/C window compressor is just fine. I was using a hand vacuum pump before this. It took a while to pump out. I've even used a hand vacuum pump on a central system. I was pumping for almost an hour! A car's A/C system would take about 15 to 20 minutes with a hand vacuum pump. An electric pump only takes a couple of minutes (or less with a strong pump).

 

[Nocturnall]

How did you make one from a window a/c?

 

[BrooklynBay]

I removed the compressor, cut the lines, and attached rubber hose to the copper with hose clamps. I mounted it inside of a small wooden crate, and attached a switch with a plug. It works on 120 volts AC. I think the A/C was a low to medium BTU model.

 

[Glacier991]

Now if only I could find a cheap pump I would be finally able to fix my a/c so I'm not dyin in the AZ heat any more.

I admire folks who make stuff out of other junk that serves a good purpose. My hats is off to BB for his window unit AC pump. For those not as adept, there is always an under $100 2.5 CFM 110v model:

http://cgi.ebay.com/FJC-2-5-CFM-Vac...ryZ63700QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Nocturnall... your prayer is answered. Remember eye protection.

 

[BrooklynBay]

My 2 year old refrigerator had a defective compressor. It was under the 3 year warranty, so the company sent somebody over to replace it. I showed the guy my home made vacuum pump. He was impressed, and said that I should be doing his job instead of him. It would cost me out of my pocket for a new compressor if I would have done it myself with freon in addition to this.

One thing I was thinking about for a while was why can't a standard electric air compressor, or offroad compressor be used to replace a belt driven A/C compressor or refrigerator compressor? I once bought a 12 volt A/C compressor like the type they use in motor homes for refrigeration to connect in place of the belt driven compressor on my 88. The compressor was expensive, and wasn't too powerful. A compressor like an MV-50 or the type Harbor Freight sells for about $50 is much more powerful, and doesn't require a special controller. The CFM rating isn't too low either. I think it might work. Electric vehicles use a similar system for A/C, and vacuum for the brakes with electric compressors.

Another idea for an alternative compressor in a vehicle might be a standard A/C or refrigeration compressor running off of an inverter. The inverter should be capable of handling a slightly higher wattage than the compressor draws. The surge capacity of the inverter is usually much higher than the running wattage, so it should be capable of handling the cycling.

 

[BrooklynBay]

This place sells another model which is almost 3 times more powerful, but is almost 2 times the price: http://cgi.ebay.com/ebaymotors/ws/e...:PROMOBOX:NEWLIST&viewitem=&item=320127010715

 

[Nocturnall]

Glacier I love you and I read your a/c sticky and the numerous warnings to use eye protection.

 

[BrooklynBay]