intense negative pressure in apartment unit?

[oilburner]

All, I'm trying to figure out what is going on with our apartment unit. It's a new building in 2015 with boiler/radiant heat. No AC. We are dealing with very intense negative pressure that is causing a strong draft underneath the front door. This is causing a lot of cigarette and cooking odors from one of the other units to enter.

The single make up air vent is located high on a wall adjacent to front door. Also a constant strong draft coming from this vent. We are on 3rd floor of 4 story building. I'm at my wits end trying to find out what could be causing this draft entering under the door. No exhaust fans (hood range, 2 bathroom) are running. Dryer door shut and sealed. All windows tightly sealed. Any ideas of what else could be causing the negative pressure? Stack effect? Or could the make up air vent positively pushing air into our unit also be causing air to be drawn under the door?

[ammoniadog]

Are you sure there's no exhaust fan on the roof? My guess is there probably is, maybe with an exhaust grill in the hallway? Perhaps the make up air isn't working and is just getting air sucked out of it by the large exhaust fan(s) so it feels like it's working.

When I was first starting out in this trade I got sent to install a humidifier at a unit in a high-rise condo building. The lady who owned this unit had some expensive wooden floors put in and was really worried about the humidity level, which was too dry.

The fan powered humidifier I installed on her heat pump air handler wasn't accomplishing much, so I ripped it out a couple of weeks later and replaced it with a more powerful, steam powered humidifier. That one didn't make enough humidity either, so I ended up ripping that one out too and we gave the lady her money back.

What my boss didn't notice when he sold her these humidifiers was that she had the same issue as you. Her unit was in a huge negative pressure. Air was getting sucked out of the front door from the hallway. We didn't have any control over the building's main hvac system, so there wasn't much we could do. I never did find out why the building hallways were in such a negative, but I suspect it was a make-up air unit that wasn't working.

edit... I just reread your post. It sounds like you have the opposite problem of air going from the hallway into your apartment, which would indicate too much make-up air in the hallways or perhaps a main exhaust fan that isn't working (and/or not enough make up air from that vent you talked about in your apartment). Either way, it sounds like a building issue. Tell the management and hopefully they can get someone to figure it out.
By the way, where do you live where a new building can get away with not having air conditioning? I didn't know building places without A/C was a thing anymore.

[oilburner]

edit... I just reread your post. It sounds like you have the opposite problem of air going from the hallway into your apartment, which would indicate too much make-up air in the hallways or perhaps a main exhaust fan that isn't working (and/or not enough make up air from that vent you talked about in your apartment). Either way, it sounds like a building issue. Tell the management and hopefully they can get someone to figure it out.
By the way, where do you live where a new building can get away with not having air conditioning? I didn't know building places without A/C was a thing anymore.

that's correct. I'm not sure how this is happening though, if there was too much positive pressure in the hallways all the other units should be experiencing the same issue. If that's the case how is air exiting their units into the hallway and then into mine?

[James Colver]

Wow. This is gonna get complicated to fix. Someone didn't do their job right when they designed the fresh air system for the building.

[numbawunfela]

You need diagnostic air balancing. Not just balancing. An air balancer will see what you need and then throw up their hands and say 'it is broke, call me when it is fixed' if there is not enough air to go around. A diagnostic air balancer will take broke and figure out why it is broke and reccomend fixes, possibly even do the fixes.
I did classes with these guys, I really like their approach:
https://www.myhomecomfort.org/how-ef...r-hvac-system/
National Comfort Institute trains HVAC contractors in air balancing. They can then apply it to your situation. It is a good place to start. There is a contractor locator there.
Over the interwebs it is impossible for me to lay eyes on your place... if I could, I may quickly see something that is insignificant to you, but the heart of the issue to my eye.

[toptech]

the M.U.A. is not delivering enough C.F.M. for your common areas.
Have a reputable HVAC company access why.
Good Luck