CO detector quit after five years, why?

I think the sensor contains some sort of chemical electrolyte that absorbs the gas being detected - it isn't going to last forever.

Dang. I was afraid that it's something like that. I just wonder why the living room sensor has already lasted 2x that time. Maybe better technology?

Classic "YMMV".

Yeah, beats me why though. Because nobody smokes here and the wood stove where you get the occasional ash dust is right next to the living room sensor. It's the Kidde brand, maybe those last longer?

I guess any attempts to repair would be futile and I'll just have to look for a new one.

Or the built-in-test failed first?

(I'm always suspicious about built-in-test.)

Probably a replacement sensor costs as much as a new unit.

The professional O2 detectors have a large percentage of the cost in the sensor.

It would be nice if someone would come up with a cheapish one that uses a VCEL sensor.

Best regards, Spehro Pefhany

Not wise unless you are used to handling strong acids. And its calibration afterwards would be *very* quesitonable.

Are you sure that it still works correctly and would detect real CO ?

It really isn't worth taking chances with an odourless toxic gas.

Quite possible. They both have self-testing though, it's probably a legal requirement. I'll see if I can get the kind we have in the living room because that's lasted much longer.

--- From:

"Sensors[edit] Early designs were basically a white pad which would fade to a brownish or blackish color if carbon monoxide was present. Such chemical detectors were cheap and were widely available, but only give a visual warning of a problem. As carbon monoxide related deaths increased during the 1990s, audible alarms became standard.

The alarm points on carbon monoxide detectors are not a simple alarm level (as in smoke detectors) but are a concentration-time function. At lower concentrations (e.g. 100 parts per million) the detector will not sound an alarm for many tens of minutes. At 400 parts per million (PPM), the alarm will sound within a few minutes. This concentration-time function is intended to mimic the uptake of carbon monoxide in the body while also preventing false alarms due to relatively common sources of carbon monoxide such as cigarette smoke.

There are four types of sensors available and they vary in cost, accuracy and speed of response,[15] listed below. The latter three types include sensor elements that typically last up to 10 years. At least one CO detector is available which includes a battery and sensor in a replaceable module. Most CO detectors do not have replaceable sensors.

Opto-chemical[edit] The detector consists of a pad of a coloured chemical which changes colour upon reaction with carbon monoxide. They only provide a qualitative warning of the gas however. The main advantage of these detectors is that they are the lowest cost, but the downside is that they also offer the lowest level of protection.

Biomimetic[edit] A biomimetic sensor works in a fashion similar to hemoglobin which darkens in the presence of CO proportional to the amount of carbon monoxide in the surrounding environment. It uses cyclodextrins, a chromophore, and a number of metal salts. This can either be seen directly or connected to an infrared source of photons such as an IR LED and then monitored using a photodiode. Battery lifespan usually

will last the life of the product. The biotechnology based sensors have a useful operational life of 6 years. These products were the first to enter the mass market, but because they cost more than other sensors they are mostly used in higher-end areas and RVs. The technology has been improved and is the most reliable technology, according to a report from Lawrence Berkeley National Laboratory.[16] The technology is the only one tested false alarm free and is preferred by those with larger facilities like hospitals, hotels and apartments that use air fresheners, alcohols and other disinfectants where the cost of one false alarm is very high. This technology was invented in the United States and is manufactured in California.[citation needed]"

John Fields

It'd probably only last a year in my flat unless I kept all the windows shut - there's a busy bus route on the road that passes in front.

Definitely, because there'd be high shipping charges while a whole detector could be bought at Costco. I just ordered a valve for a test apparatus, a tiny thing the size of a relay. Since it wasn't urgent I chose the cheapest ground shipment option. A whopping twelve bucks!

This is similar to the one we have in the living room, seems to last forever:

-Lasse

The idea that calibration might be needed was at the back of my mind, but I didn't know so didn't say anything.

IWHT calibration alone would wipe out any saving over the price of a new unit.

One I bought some time ago for an elderly relative recently started making fault warning beeps - new batteries didn't help.

I vaguely remember something on the original packaging about a 5 yr service life.

In the UK, if you mail order goods from abroad - Royal Mail extort a racketeering 'handling fee' to collect any duty on the goods.

I've heard that private carriers are even more predatory.

Den torsdag den 8. maj 2014 22.53.00 UTC+2 skrev Ian Field:

here I think it is pretty much the same for all of them, around 20 euro

anything under ~10 euro including shipping is exempt from both VAT and the handling fee

-Lasse

How do you know the one in the living room is "fine"? Maybe it's just not complaining.

Q1: Why do you have a C0 detector? A1: So I don't get dead. Q2: Why do you want to save a few bucks on a questionable detector? A2: Cuz I'm cheap.

You have just equated the value of your life with the value of a new CO detector.

Every few years, I watch for sales and replace the oldest one in the house. Hopefully, at least one of 'em is still working...cuz I don't want to get dead.

Or, worse, come home and find your entire family dead from CO poisoning, as has happened many times.

Best regards, Spehro Pefhany

But its the most painless way.