UEi Test Instruments CD100A Combustible Gas Leak Detector

I am an HVAC service tech. This combustible gas detector is a professional quality tool, it works exceedingly well and is unbelievably sensitive. It’s sold at a number of HVAC parts houses. It detects basically any combustible gas at levels at least as low as 50 ppm (parts per million).It is not auto-zeroing which I actually prefer. That means it doesn’t automatically desensitize itself with exposure to combustible gas. You can adjust the sensitivity yourself as needed meaning you can decrease sensitivity as the area is saturated with gas and you zero in on the leak and at ANY point you can crank the sensitivity back up without having to wait a long time or restart the detector & move back outside. It also means when you initially start it up you have to adjust it to the required baseline. Give it a minute or two to warm up & adjust it to a few clicks per second.I’ve used this detector at least 8 or 10 times so far. It pick up instantly with no delay & recovers very quickly. On both accounts it is MUCH better than my previous detector. It is also INSANELY sensitive and I mean CRAZY sensitive. A funny experiment, it’s so sensitive that it will detect methane when you put it close to anyone’s rear end and that’s when they are not passing gas.The point being, don’t let the extreme sensitivity of this detector drive you crazy. It WILL pick up on the most insanely small “leaks”. I would suggest confirming all leaks found by this detector with a bubble solution. Not because of the reliability of the detector but because the leak could be so small as to be insignificant. Gas lines typically hold no more than 2-3 PSI of gas (on your side of the gas meter). They are tested & passed at 10 PSI. By their nature, gas lines are not exceptionally tight. Most gas lines, if pumped up to 10 PSI & left for a week, will have lost a good amount of pressure. My point being, if you find a leak with the gas detector but it won’t show up with a bubble solution PROPERLY ADMINISTERED it’s too small to worry about. You could search the entire gas line on a small old house & probably find over a dozen “leaks” that small and it could still pass the pressure test.Here’s another pointer, sometimes it’s normal to smell a little gas. What? That can’t be right? Your gas meter has a pressure relief on it. It will, from time to time, purge a little gas, especially when gas appliances are turning on & off. Just because you smell gas when you walk by the meter doesn’t mean there’s a problem. When your gas furnace shuts off the gas valve closes and the gas inside the distributor equalizes to the ambient pressure, but it’s inside an enclosed tube so not every last bit gets blown out of the flue by the inducer motor. Everything shuts down and over minutes that tiny amount of gas slowly dissipates. If you pull the door off the burner compartment of your furnace at the right time you’ll smell gas. This detector will pick up on it. It’ll hit big right at the orifices where the gas comes out. That doesn’t mean there’s anything wrong.What I’m getting at is, be safe with gas but understand just how sensitive this detector is and if you’re not sure what is or isn’t normal call a professional. The professional would be more than happy to have this detector in his arsenal of tools.

I originally bought this to help troubleshoot a propane stove in my Airstream, which I suspected was leaking. There was just a touch of a long-lingering gas-like odor, but many of the gas connections were too hard to reach to try testing with water and soap. After reading the reviews, and cringing at the price, I finally ordered one.I was excited when it arrived. My foray into serious, committed gas detecting had begun! The unit has a bit of heft, and feels well made. And, it's super easy to use. After inserting a battery you simply spin the dial to turn it on and then increase the sensitivity, until it starts "clicking" repetitively in clean air. Extend the flexible probe, and start poking at things you think might be leaking leaking combustible gas (i.e. propane). If it finds even a little bit of stray gas, it starts clicking faster. If it finds a major gas leak, it clicks so fast that it sounds like it's buzzing. Think Geiger counter.So, I started probing around near my gas stove, where I thought the leak might be. Nothing. Because of the long probe, it's easy to press it up against each individual fitting to see if it's tight, or leaking. I pressed it against each fitting going to the stove. Still nothing. Could my dual electric/propane refrigerator be leaking? I checked each connection on that, too. Still nothing. Maybe the detector wasn't working? I turned on my gas oven, without the pilot being lit, and held the probe near the gas outlet. The detector immediately went crazy. So, it was working. To make a long story short, there was no leak. It turns out that my old carpet was just really smelly. No, not kidding. But I wouldn't have known without the detector.So, it turns out that a sensitive detector is useful not just for finding gas leaks, but also for determining that there really is no leak. But, my detector hasn't been sitting idle. In the meantime, I've used it to check every visible gas connection in my house for leaks. It's helped me pinpoint a propane leak in my camper shell. I just used it to check every new propane joint after having to replace my dual propane tank automatic changeover regulator after it failed, and it almost instantly found a couple of leaks which allowed me to quickly fix the bad connections. And, it even helped me troubleshoot a loose gas connection in a house I sold recently, after the home inspector flagged a gas leak. Without this unit, I would have had to call a contractor to trace it. Instead, I was able to quickly find the leak and fix it myself, which turned out to be nothing other than a loose connection without the sealant which it should have had. That alone more than paid for this unit. If you hold this up to someone's mouth, you can even tell if they've been drinking. Don't ask me how I know.Not trying to sound like I'm an expert here. I'm really just a regular DIY kind of guy that likes to work on relatively easy stuff. But, if you have an RV, or a house with natural gas, or do any kind of work whatsoever with propane, or natural gas, or RV systems, this awesome tool can give you a "sixth sense" to find that (possible) gas leak. It helps you quickly determine (1) is there a leak? (2) if there is, exactly where it is, and (3) based on #2, the added ability to help determine if it's something you can fix yourself easily, or if it's maybe time to call in the real experts.

This really works. I smelled gas from a connection to my furnace. The plumber resealed and tightened the connections. No smell, no bubble leaks.But still got a leak reading. Other joints did not get a reading, so the plumber replaced the small pipes, new sealant dope and now no leaks.The downside is this is so sensitive, it detects leaks which a plumber may not normally try to fix. Maybe it was the old sealant or something that was smelling. Anyway it works great, but be award, you may drive your plumber up the wall with this thing.I did ask the community how much background noise is acceptable inside the house. We get a faster ticking throughout the inside of the house. EDIT, Update. After a couple of weeks, the background noise went away in side the house.That tells me that our house was full of the bad air, and am so thankful I have this to check the air now.