Hi all, I have a newly installed Santa Fe ULTRA120 dehumidifier for our upper level. House is 3500 sq ft, Durham NC, and very airy with a two story living room. A separate return duct was installed in the second floor ceiling, connects to rectangular ducts between attic joists, and it transitions to a 10" insulated duct in the attic before plugging into the dehumidifier inlet. Outlet goes into the supply plenum of the air handler through 10" duct with a backdraft damper. Fresh air inlet damper of the dehumidifier is closed.
When the dehumidifier kicks on (with the air handler fan), warm air comes out the supply vents and the humidity in the house increases. It comes back down at night. The dehumidifier is producing water continuously in the drain pipe, so it seems to be working.
Local HVAC tech came out today, couldn't find any leaks, and thought the problem was that the air handler fan is running with the dehumidifier. He turned that setting off, left, and the house temp and humidity promptly skyrocketed. Not surprisingly I could feel no air movement through the registers as the dehumidifier fan is not powerful enough to push air through the entire system. Dehumidifier is now back off.
Any thoughts? Seems like dehumidifier could be pulling in warm air from attic, but no leaks are apparent. Attic is super hot this time of year. Other thought is that the return air is getting warmed by the 10 foot run through the rectangular ducts in the floor, which are not insulated, but enough to make that much of a difference? RH in the house is around 60-65% with existing HVAC systems set at 72.
Thanks guys
David
When the dehumidifier kicks on (with the air handler fan), warm air comes out the supply vents and the humidity in the house increases. It comes back down at night. The dehumidifier is producing water continuously in the drain pipe, so it seems to be working.
Local HVAC tech came out today, couldn't find any leaks, and thought the problem was that the air handler fan is running with the dehumidifier. He turned that setting off, left, and the house temp and humidity promptly skyrocketed. Not surprisingly I could feel no air movement through the registers as the dehumidifier fan is not powerful enough to push air through the entire system. Dehumidifier is now back off.
Any thoughts? Seems like dehumidifier could be pulling in warm air from attic, but no leaks are apparent. Attic is super hot this time of year. Other thought is that the return air is getting warmed by the 10 foot run through the rectangular ducts in the floor, which are not insulated, but enough to make that much of a difference? RH in the house is around 60-65% with existing HVAC systems set at 72.
Thanks guys
David
source https://hvac-talk.com/vbb/threads/2240319-Whole-home-dehumidifier-raising-humidity?goto=newpost
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