Automotive Air Conditioning Information Forum (Archives)

Kester 245 on Thu September 09, 2010 4:28 PM

Year: n/a
Make: n/a
Refrigerant Type: 134a
Country of Origin: United States

I have an electronic leak detector that used a heated pentode. I thought it performed good with 134a the few times I used it until it suddenly went DOA.....won't even turn on. I see the newer technology uses an infrared ? sensor. Comments welcome as I need a new toy. thanks

Dougflas on Thu September 09, 2010 4:42 PM

I recommend either a Tek-Mate or the H10 battery version. The TeK-mate is a great unit for the money. Uses "D" cell batteries that last a long time.

They sell for approx $150. The H10 uses a rechargable battery. This unit costs approx $400. I like this unit for being able to zero in on the leak as you can manually adjust it.

NickD on Fri September 10, 2010 5:08 AM

Key criteria is sensitivity, should be able to detect a leak of far less than one ounce per year. Also using one, has to be done in a draft free space with a cool engine as a hot one generates convection currents. Also needs quite a goose neck as refrigerant is heavier than air and will sink down. May have noticed, many very tight areas to work in with MVAC.

Some of the detectors I have seen would work fine on a MVAC that is laid out in a two dimensional layout, hung from a ceiling. What were they thinking when they designed these? Or is thinking old fashion?

chris142 on Sat September 11, 2010 10:26 AM

We had one of those black box ones that plugged into the 110v outlet. It worked well. It died and we bought a battery operated Robinair model. Totally useless. I then bought another battery operated one from the Mac truck. This one is useless too.

Neither of the battery operated ones will pick up the leak unless you crack open a fitting and you can actully hear the leak then they work.

NickD on Sun September 12, 2010 7:37 AM

Tantamount to see what you are doing, many times it is necessary to hold a small battery operated flashlight in your mouth in tight spaces as opposed to trying to drag in a large AC powered trouble light where the cord gets tangled around your neck. But AC is nearly constant as opposed to a battery where the voltage can deviate 25% over its life.

Really no problem if a precision stepup switchmode well regulated power source is used with a battery to maintain a precise operating voltage for the halogen detection circuitry.

Most use a very tiny capacitor as the sensor where halogen gases have a slightly lower dielectric characteristic than air that must be well shield from the surrounding metallic environment. Only the presence of even a small amount of halogen gases should affect the capacitance of that capacitor that is used in a very high frequency oscillator. Has to be a high frequency to produce a reasonable change in frequency with even the tiniest bit of capacitance change due the presence of halogen gases.

To make this frequency audible is heterodyned with that of a near same operating frequency of an RC oscillator that is controlled by a precision well shield potentiometer, not a cheap ass carbon one that is not well shielded. This is adjusted to create a beat frequency that sounds like a slow moving set of blimps to your ears that increases or whines if you may when exposed to even the slightest amount of halogen gases in terms caused by leakage rates of less than one ounce per year. Not very much.

Rather than comparing AC as opposed to battery operating, would compare a piece of crap detector as opposed to one that is very thoughtfully designed and laid out with good immunity to the surrounding metallic surfaces.

If you can't find a good one, like anything else, you modify it to your liking. If either the sensing or RC oscillator shifts with voltage fluctuations or are unstable in design, user doesn't know the difference between that or the presence of even the smallest amount of halogen gases. Even more Made in China crap on the market that you can't do anything with except invest in even a larger trashcan.

Doing business with China is going to be and is the downfall of this country, we have the brains and the skills here. Or least did at one time. Currently concentrating my efforts to piercings, tats, and obtaining a large collection of rap so I can be like everyone else.