RYAN HOMES Defects and Damages 

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Carbon Monoxide (CO) exposure from our HVAC system


Note about CO test results: 

The test was performed using the Nighthawk digital CO detector (pictured below at peak display during the test). This was the best CO detector we could find in a retail store. The test was done just after the openings in the return duct end cap were discovered, prior to having them sealed with caulk. Peak levels of 17 PPM of CO had already been detected coming from the duct vent, during a period heat was being used regularly from the heat pump. This low level did not set off an emergency warning alarm, however, the level is still considered dangerous. The video recorded test results shown below were done prior to sealing the upper air return duct and end cap, to verify and record that CO was in fact coming directly from the duct work when the electric heating coils were energized. The end cap was later sealed and a second test was done. CO was still detected at up to 8PPM after sealing the end cap, and some soot production continued. This was believed to be from contamination residuals and possibly other cellulose leaks. Cleaning and a higher quality air filter prevented measurable soot and CO production in a final test. Although CO and soot production are currently non-detectable, heating was only briefly used because noxious odors persisted from the HVAC system, with symptoms of headache, nausea, and dizziness resulting. 

(ADDENDUM: The duct work has been cleaned and the entire heat pump was removed inside and out, including the contaminated air handler- which was correctly installed this time.)

Test notes: Heating unit "off" time was determined by deactivation of the secondary electric coils. This is the only part of a heat pump that could produce significant CO levels, provided the coils were in direct contact with combustible materials. When temperatures are above freezing outside, a heat pump seldom energizes the electric coils. Below freezing, the heat pump loses the ability to produce sufficient heat, and draws on the secondary electric coils increasingly as temperatures fall beyond it's range of efficiency.

In this part of the country, there are typically, but arbitrarily, many days and nights where the temperature are well below freezing. The electric coils were almost continuously energized during cold snaps that could last for weeks. This meant the low level CO production didn't cycle up briefly then back down, as in the test above, but was continuously maintained or even building to higher levels than we could measure. Short term exposure to low level CO is not critically hazardous to health. However, long term exposure to low levels is cumulative in the human body. CO levels in the body would steadily increase with exposure to continuous low levels of exposure, and become health damaging or even fatal.  

It is unknown how high peak levels actually accumulated to, as the CO measurement device was only used for a short time. As soon as we saw CO, we shut off heat, and contacted the fire department to see if we were in any immediate danger. I talked them out of pushing the alarm button and sending out trucks for an emergency call, as the CO levels clearly went down with heat off.  The low levels detected are know to be above acceptable levels for human safely by OSHA standards, according to an OSHA representative. Eight hours a day at 8ppm is unsafe. We had 24 hours a day exposure to levels much higher than OSHA tolerances. The only people who found this issue frivolous were the people that caused it- Ryan Homes employees.

TO date: The CO detector has been operational for five years continuously since repairs were completed. Peak CO level recorded by it's internal memory to date <zero>.