CO detection, TPI775 meter different from gas co.

On a recent inspection I noted high (35ppm +)levels of CO at the heat outlets (gas forced air furnace - I’m in Canada). I was actually in the house on two different days and took readings at two different times on both days with similar results. Each reading was taken over a 15 minute time span. The seller is in denial and had the gas co come out to check. They gave a report saying no problems.

  1. is anyone else using the tpi775 meter? have you ever suspected false readings?

  2. is there any condition in which a furnace can give off differing levels of CO? Can the length of time the furnace has been running influence this?

When was the last time you had your meter calibrated?

I’ve had this meter for about a year and a half.

There are variables such as down drafting.
Filter should be changed every year with heavy use.

Consider a training course such as this:

Measuring for CO in ambient air is not as simple as waving the wand of your meter around a supply duct. Many inspectors do not understand or realize this.
Calibration of your equipment is important as well.

Try calibrating , But keep testing. I had a furnace guy denied there was a problem the agent insisted it be checked . Seller agent said i was being to picky. They sent a fellow in he found 3 small cracks. Trust your tools but keep them updated. test it where you know the air is clear. so far sense i started checking i have found 5 furnaces with problems Kinda makes you wonder how many problems are hiding.

Wayne the “Deal Killer”