Too much "suckage"

[DevoBuzz]

When my blower fan comes on (either during heating or A/C) there is so much negative pressure in the basement (where the HVAC system is) that my basement door shuts. Is this cause for concern? All my return registers are open and unobstructed. I'm wondering if this will cause a poor efficiency of the heating or cooling of the house? If so, how should I correct this?

Thanks,
Ralph

[t527ed]

return ducts need to be repaired. the big danger is you are probably sucking a backdraft on your chimney.

[RyanHughes]

return ducts need to be repaired. the big danger is you are probably sucking a backdraft on your chimney.

That's not good. I experience the same issue. If my basement door is slightly cracked, the return that was added to the basement (I assume when it was finished) can pull the door closed. If the door is open enough, it won't happen. It looks like they just cut a hole into the return trunk, so the force isn't surprising. My basement door is right off the room that has the chimney.

I also wonder if this is the reason why I don't get as much return airflow into the upstairs return--because of the return cut into the trunk right by the a/h.

[t527ed]

That's not good. I experience the same issue. If my basement door is slightly cracked, the return that was added to the basement (I assume when it was finished) can pull the door closed. If the door is open enough, it won't happen. It looks like they just cut a hole into the return trunk, so the force isn't surprising. My basement door is right off the room that has the chimney.

I also wonder if this is the reason why I don't get as much return airflow into the upstairs return--because of the return cut into the trunk right by the a/h.

sucking the basement door shut is always a bad thing, where will it suck from when the door is shut??

[RyanHughes]

sucking the basement door shut is always a bad thing, where will it suck from when the door is shut??

I would think the basement itself? I do have 4 supplies in the basement and a return that I believe is 14x14. I do try to make sure the basement door is left open. The basement hallway essentially acts as one big return plenum. I do have one return on each floor.

[bmathews]

You just need a passthrough. That will take care of your problems.

[t527ed]

I would think the basement itself? I do have 4 supplies in the basement and a return that I believe is 14x14. I do try to make sure the basement door is left open. The basement hallway essentially acts as one big return plenum. I do have one return on each floor.

if it is sucking the door shut there is not enough supply in the basement for the size of the return, you are putting basement into negative pressure.

if you have a gas water heater in the basement fell around the bonnet opening when the basement door is shut and a/c is running.........

[canesfanforlife]

When my blower fan comes on (either during heating or A/C) there is so much negative pressure in the basement (where the HVAC system is) that my basement door shuts. Is this cause for concern? All my return registers are open and unobstructed. I'm wondering if this will cause a poor efficiency of the heating or cooling of the house? If so, how should I correct this?

Thanks,
Ralph

You should have your duckwork checked by a qualified contractor. Lack of ductwork cause the system to draw air from from anywhere it can. If the door is closed it will suck it from the cracks around the windows, doors, any draft vents of any gas appliances, even from gaps around light switches and outlets. Not only is it very inefficient but it will also bring in outside air pollutants.

[beenthere]

Devo.

You don't have enoguh return.
You need to have a contractor to check your system to see what can be done to fix the problem.