Power down unplug eca and power up unit config's itself at power up. If it don't see it it don't know it's there.

 

I second that.

 

I think there's more than one way to skin this cat.

These units are available without an economizer. There is (should?) be some way to disable the economizer on the RTRM board. (answered by nytrane)

Since there is no feedback from the actuator, taking control of the actuator and leaving the economizer intact should work.

You could work with what you have. There is a remote minimum position feature that could be used. Also, a CO2 input could get the OA open as well. You'd have to deal with Trane's IAQ PID loop if you went this route.

 

Shut her down ,yank the plug on the economizer module, power it up , Done .

 

Why do you want to run the economizer on space pressure? It sounds like you are trying to fix a poor design by cutting off economizer operation. Depending on the size of the RTU, an accessory power exhaust is the first step correction.

 

Here in CT economizers are pretty much useless. the temp change is too dramatic to bother with , so I disable them when they begin to have issues. On the other hand , if you live in a place where the temp is stable for an economizer to work well , they are a great money saver.

 

If you disable the enonomizer... What are you going to use to bring in outside air for your xxx cfm per person?

 

If you are asking me this question , please let me clarify. I only deal with restaurants and the equipment that they use. the units that I speak of are air-side economizers used for free cooling.

 

county does our inspections...and they are not that detailed. Small jobs i set them larger ones we have a balancing contractor set them. 5 ton unit with a 1/4 in gap is plenty i was told.

 

Upon reading up on the subject of indoor air quality,I realize my mistake by doing this. I will go back to these units to correct. 25 CFM per person in a restaurant? Thank you guys for pointing this out to me.

 

So, are you suggesting that the front door of the restaurant opening constantly during business hours is NOT giving you enough air exchange to satisfy ASHRAE's requirement for fresh air? How about the make-up air in the kitchen, is it sized to ONLY make-up what the exhaust hoods are removing? In a perfectly sealed building with an absolute air lock at the front door and absolutely NO leaks anywhere else in the building, 25 CFM per potential occupant AFTER you account for ALL exhaust fans MIGHT be necessary...if you have a building like this let me know, it might be worth saving my money for the trip to the moon to see this building!!!

I think someone already mentioned the fact that even with an economizer damper at 0% there is enough air leakage to provide for fresh air requirements. Now, if you are going to control the economizer based on pressure, are you planning to open the economizer when the space goes to negative pressure? How about a CO2 sensor instead? Set your setpoint to 800 PPM, go above setpoint, open economizer...everyone breathes easy

I don't know...it has been my experience that economizers cause more problems than they solve. 100% pre-conditioned fresh air is the proper way to provide outside air without introducing moisture into the building. Most building owners don't want to spend the money to do it that way and end up with mold problems and can't figure out where they went wrong, but that's because there hasn't been enough engineers sued over bad design..."that's the way we've always done it, it's never been a problem before." No, you have just never been sued over it!!! But I digress.....

What were we talking about?

 

I have always felt that there was plenty of fresh air coming into a restaurant on a daily basis. doors are opening all day long. I need to research this further. co2 detectors are in place near the tanks , but not anywhere else to check that as it is heavier than air and not required in my state. I will repair the economizers until I am sure of the issue.

 

Low Ambient Operation

What are you going to do about low ambient operation? A Trane Voyager we have, during low ambient, compressor is locked out thru the O.A. sensor which is part of the economizer. You'd have to add head pressure controls, above what the unit already has and put another low ambient control for a lower setting.

Does anyone have the instuctions for the Economizer Module, Trane P/n MOD01670 Honeywell P/n W7399B1002 ? Also, what test resistor do you use to put the unit into Econmizer test mode? Do you leave it hooked up, or momentary contact it to test terminals ? Everything seemed to work after I replaced OHS, and Module, but was getting bums rush to get off job.

BTW all decals, booklets have been stripped out of this unit. Their quest for job security didn't work so now I've got the unit.

RTU Unit I.D. ____R 1_____ Manufacture ______Trane______

M/n ____TCD420AE0R2A7FE5AB0D0F0HJ000000______

S/n ____C05E04734__________________________________