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Basement Dehumidifier Install into Existing HVAC

362 Views 1 Reply 2 Participants Last post by  user_12345a
Just finished my basement and I'd like to install a dehumidifier and tie it into the HVAC system. I have a 3 zone system working off a furnace with a/c. The basement is on its own zone with the other zones for 1st floor/2nd floor. Looking for the best way to tie in a "whole house" dehumidifier and only connect it to the basement zone. See pictures attached which show the existing system as-is today (not showing 1st/2nd floor zones) and my proposed setup with dehumidifier. The dashed lines show the utility room outline. Essentially, I'd like to tap into the existing return system and supply dry air through the basement zone supply ducting. My questions are:
1) What, if anything, do I need to do to ensure that if the HVAC system is running for the 1st/2nd floor systems that the flow doesn't reverse or overload the dehumidifier fan when/if the dehumidifier is running. It appears that these dehumidifiers have a static pressure requirement for the return plenum...I assume that is a minimum (i.e. must not go below that value or the flow will reverse and/or overload the dehumidifier fan)? If so, I should be able to measure that to confirm.
2) What dampers, if any, should I install in my proposed setup?
3) Do these dehumidifiers have a cut-out so that it doesn't run when the heat or A/C is on for the associated supply zone to avoid reverse flow/fan overload? It appears the dehumidifer controls can be tied into existing zone controls, assume that's what it's for?

Thanks in advance.


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The dehumidifier's fan won't be able to overcome the pressure in the supply duct.

Take the air from the basement and have it dump dehumidified air into the return.

The most humid air is in the basement and the drier the air is going in the less efficiently these units operate.

No dampers required.
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