Is there anything I can do about this?

[RomulanSpy]

At my work (large high school) 2 conjoining rooms share a common A/C / furnace. The A/C is a 4T Trane (last of the R-22's and we got it on the cheap) and it was installed in April. The previous unit was a 4T Trane. These unit have supplied conditioned air to about 1800 ft2 between the 2 rooms.

The AH was put in when the building was constructed in 1993. The blower and the inside of the AH is filthy. Still, it keeps on going. The problem is w/humidity. If you leave it set on 76-78* like the electricity usage Nazis command, the rooms stays as humid as a jungle, you have to cut the t-stat down to a crisp 72* for the rooms to dehumidify and of course they're as cold as heck.

Another thing that exacerbates this, is that state law says that a damper has to be open to let in a % of fresh (read humid) air. I understand this b/c of potential CO emissions. Still, this does not help me. Papers curl, flooring buckles, girl's hair frizzes, and its a real b**** to put up with.

Short of buying a dehumidifier (at my own expense, mind you) what can I do about an obvious stupid install????

Thanks once again
Rom

[Shophound]

Having the air handler thoroughly cleaned is a great place to start. If it is plugged up with dirt/dust, it can't move as much air as it should. Not moving as much air as it should means not enough air volume of the room passes over the cooling coil to be cooled and dehumidified. Dirt/dust on the cooling coil itself acts as an insulator, preventing the cooling coil from removing as much sensible and latent (moisure) heat as it could.

Clean 'er up and let 'er rip at 75^F, and see what happens.

[beenthere]

Besides the cleaning.
The blower can set to low speed to help some.
Also, a some what more restrictive air filter may help slow the air down, if the school won't slow the blower.

[smokin68]

You can start by having the blowers/ airhandler cleaned out and properly checked. I'm all too aware of today's OA requirements, which at 15 cfm/ person can add a large latent load on the system. The 4 ton sounds too small for the application, as it should be a staged system also to provide humidity removal. We also put sensors on our systems to open the O/a dampers only when the rooms were occupied....we used motion detectors w/ a time delay board.

[adrianf]

Show the unit to a parent. email maintenence.

[RyanHughes]

New Trane on an air handler from '93? Both 10 SEER?

[dash]

How is the fresh air connected?What size duct,is it filtered?

Is there an exhaust fan to pull fresh air in?

We have seen some jobs that were getting three times the fresh air needed,due to the setup.

Fan speed needs to be set,by testing of some kind,static and fan chart is one way.

[RomulanSpy]

Besides the cleaning.
The blower can set to low speed to help some.
Also, a some what more restrictive air filter may help slow the air down, if the school won't slow the blower.

but that's wasn't y MO to do that. I bought (again at my own expense) 3M Filtrete Maximum Allergen (the 20 buck kind at HD) mainly b/c this thing spews dust thru the near-invisible filters the janitorial staff installs.

Thanx Been, glad to that I might have helped my situation w/out meaning to.

[RomulanSpy]

Show the unit to a parent. email maintenence.

That's a friggin good idea.

[RomulanSpy]

New Trane on an air handler from '93? Both 10 SEER?

Yep. Our school system spares no expenses, we deaux things right-----the 3rd time!

[adrianf]

but that's wasn't y MO to do that. I bought (again at my own expense) 3M Filtrete Maximum Allergen (the 20 buck kind at HD) mainly b/c this thing spews dust thru the near-invisible filters the janitorial staff installs.

Thanx Been, glad to that I might have helped my situation w/out meaning to.

That all depends on where the filter is in relation to the fresh air intake.

[RomulanSpy]

How is the fresh air connected?What size duct,is it filtered?

Is there an exhaust fan to pull fresh air in?

We have seen some jobs that were getting three times the fresh air needed,due to the setup.

Fan speed needs to be set,by testing of some kind,static and fan chart is one way.

Fresh comes thur an open damper under the AH, it doesn't have its own filter but is combined w/the return air from the rooms

No exhaust fan, I THINK the blower pulls in the fresh air too. Not sure.

Good Q's I'll run 'em by maintenance

[dash]

Fresh comes thur an open damper under the AH, it doesn't have its own filter but is combined w/the return air from the rooms

No exhaust fan, I THINK the blower pulls in the fresh air too. Not sure.

Good Q's I'll run 'em by maintenance

Where is the filter,in the unit or at a return grille??