Explaining process to help
I have Two seperate bldgs that both have newer versions of Varitracs in them
I do not have models of systems. I want to explain to the client the process
used to define and solve the various hot and cold spots and other problems. Although it should be easy I am having trouble putting thoughts to paper.
Does any one have a written process for going in to the bldg, figuring where the problems are . the repair part is easy once we know what is wrong.
First you need to identify the type of complaint from the tenant/occupant. Usually I narrow it down to 2 types of problems.
1.) Hot or cold complaint: They are complaining about the temperature in their space.
2.) Airflow issues: There are many, drafty, stuffy etc..
Once you know the type of problem that they are complaining about you can begin a systematic approach. I like to break things down. Primary / Secondary. You can look at Waterside Equipment & Systems, Airside Equipment & Systems and Misc. Equipment & Systems.
Start with the primary systems. If it is Rooftop Units or Air Handling Units check the basics;
Unit is indexed to occupied, fan status, supply air temperature, economizer/mechanical cooling switchover, static pressure, VFD output etc..
If it related to a system wide problem like Chilled Water / Hot Water then check the Chillers/Boilers/Heat Exchangers/Cooling Towers/Pumps look for;
Ensure the equipment is operating, that the associated circ pump has proof or status, that the reset schedules match the supply H2O etc..
If the primary equipment / systems look good then go down to the terminal equipment level. If it is VAV Boxes, narrow down a specific group/area/zone. If you have tabular/matrix data check that area. Then narrow it down to a specific VAV;
Check actual space temp with a good digital thermometer and compare with the reading at your Trane Tracker/Tracer 100/Tracer Summit front end. Check that the CFM is correct, damper position, min/max settings are there, heat/cool setpoint are correct, if it is fan powered (depending if they are parallel or series) fan status, if it has local heat (hot water, or electric) verify the stages are working and so on.
There is alot to cover w/o knowing exactly what those buildings have for HVAC Equipment & Mechanical Systems there are many other things you could do. This is a quick breakdown.
Depending on how many monitoring points your system has and the reliability (accuracy/calibration) of your Field Devices (temp sensors, static pressure sensors, CFM etc..) will depend on how well you will be able to utilize the control system for troubleshooting. No matter how good it is you still have to visit the space and do a visual on the associated equipment. If it is an intermittent problem setting up trends can be helpful to find a certain time or specific condition that occurs that might cause or contribute to the problem.
If it is a complaint related to odor, then you need to start with the unit, exhaust fan, economizer etc..
For any problem I like to start with the primary system (Chillers/Boilers/Steam Converters/Pumps) Then the RTUs/AHUs and then work down to secondary (Unit Ventilators, Fan Coils Units, Heat Pumps, VAV Boxes, BB Rad Zones etc..) and of course the Temperature Controls (Building Automation System/DDC Controls) Could be a bad end device, programming problem etc.. But before you blame it on the controls be sure all the mechanical equipment is operating correctly first.
Last edited by twisted pair; 02-11-2007 at 07:30 PM.
I just wanted to say thank you