[gribble]

First time poster... Desperate for properly working AC.

Small business in Denver, approx. 1200sqft, had a new Rhem roof unit RRKA-A048CK10E (Cooling 48,000 BTU) installed w/ Honeywell Economizer. Operating 25 computers, 25 people, 4 Vending machines. Open 24 hours. Try to keep temp at 72.

Winter heating/cooling the unit works great. Spring/Fall when days are hot and nights are cool/cold, AC works great during the day and and night its HOT HOT HOT. Summer its a crap shoot, some days are cool and comfortable, others are HOT HOT HOT.

Temp Fix: Keep fan on all the time, turn off AC for a few hours during the night and a half hour or so during the day. Seems to keep the unit working without the temp soaring over 80+.

4 technicians, different companies said we don't need to do that, should be cool all the time. All have also said the unit is in perfect working order and they can find nothing wrong with it.

Looking for options, and an HVAC techie in Denver.

 

[makinmoney]

System is UNDERSIZED, from what you describe as your heat load, it doesn't sound like your system was set up for the application in the space that your in. You have both sensible and latent heat load. It doesn't appear that your mechanical systems were sized to your needs.

 

[cooter2506]

true very undersized. Local supply company should be able to size you a proper unit if you give them all the needed info

 

[joken]

Correct. The system is undersize.

 

[needlevalve]

Add power exhaust to your econo, lower your ambient/enthypy setting and add head pressure control to condenser. You really are asking a lot of this unit. Keep doors & windows closed. There are many capable service techs. Finding one should be easy start by looking around the tall buildings to see who's service van is parked there.

Good Luck

 

[b2mhg]

Wow! Sounds like you building is undersized as well! 25 people in 1200 s.f.

Call Center?

 

[beenthere]

Economizer set wrong.

With the amount of fresh air your to be bringing in, its under sized also.

 

[markwolf]

It keeps up in the heat of the day & gets hot when cool out.THIS IS NOT A SIZING ISSUE!Beenthere is right.It is a common complaint with economizer systems.If you have a basic setup you may want to add enthalpy controls.This would keep the unit from economizing when the relative humidity levels are high outside.You may have enthalpy controls already but they are set for to high of a humidity level.It also may help to set the on temp slightly lower for economizer.Economizer's seem to be a magical mystery to many newer tech's IMO.I would ask your contractor to go over the economizer.

 

[Diceman]

I would never turn that thing off, what for?
I dunno, if it is struggling when it's hot out and the nights are hot, sounds too small.
Ya could play with the economizer too I guess.
At this point consdier adding on a mini-split unit to boost the cooling when needed.

 

[makinmoney]

You can play with the economizer til your blue in the face. That system will never turn off due to the amount of cooling required to cool the space, in the winter it will work fine because of the heat being generated in the space itself.

It is a SIZING ISSUE!

 

[jimbob73]

Minimum economizer(outdoor air) setpoint? Where I am, They raised minimum outside air requirements to 25 percent. That is just flat out crazy. How will anything cool/remove humidity on a 90 plus day with bringing in 25 percent outside air Especially when the unit was designed for 90 degree outdoor temp. If the unit has enthalpy control for economizer, Set to minimum of C or D.

[Edited by jimbob73 on 06-18-2006 at 12:13 AM]