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we are trying to get input from BAS, if the nozzals are the right size. Thanks for all the input. I will get all of you posted.

Hi, we have 2 2-cells bac 1500 cooling towers,( total 4 cells). each cell 1125 gpm, 3 tower pumps, each 1500 gpm. Right now, one pump with all cells are fine. When we turned the last two cells one,...

mechdesigner4controls, thanks for all the input. They are very helpful. For my system, we have both economizer and wheel. So I am not sure if we'll have such a complex whell control. We won't have...

Thanks for all of you. It seems we are on the right track. We have the filters on both oa and return and we have the by-pass damper on both the path of the wheel. Once again appreciate all of your...

why if we shut down the wheel, we'll ruining the wheel? I am not good at wheel at all. Is this for freeze?

For Ahus serving classroom, gym, offices under north ohio public school systems, it requires those units have both heat wheel and economizer. Any one familiar with those? How those are controled?...

we had the same problem on a 150 Carrier chiller before. The second loop won't be on. It turns out there was a thermostat on this circuit was dead. As I am not expert on chiller, I don't know exact...

i heard lon has to use some special chips. Backnet is just a potocol, which is very open. I do see Backnet has more market share now. But we use Lon more THe reason is we deal with lots of building...

I don't think it is very hard to write a standard control sequence. You can find them either in books or by the contruction document. I do believe the start up, trouble shooting part is the key....

i am not sure if you have a bigger pie of the bussiness in your town than the other guy. If this is the case, let things go seems make sense. We don't want people to be desperate, do we? If you are...

i have done this calc. to size the expansion tank. basically you should have a chart, which tells for every size of pipe, how much volumn is there per foot. you should be able to find the chart in...

i have done this calc. to size the expansion tank. basically you should have a chart, which tells for every size of pipe, how much volumn is there per foot. you should be able to find the chart in...

Thank you for all of your input. I have been confused by this for long time..

please advise what's the difference between those two control valves. Thanks!

ashrea publishes a rule for places like church, if it is just used for less than 2 hours, and your turn unit on and off one hour before and after, you can cut the oa 50%.

i have seen no guideline for different velocity on supply and return. it really relates with where you put ductwork(ceiling, shaft?) which kind of system you have(high low pressure) and the function...

If you don't have a discharge section, your discharge opening would be around the same size of the centrifugal fan discharge. Centrifugal fan needs the velocity to generate the pressure. That might...

Taco has a new system generating software and they are giving our free demo. cd. you might give a try. depends on your system, you might have good amount of accessories to add on.

ashrae on-line library has a good amount of books you can use. for the drawings, i don't know where you can get. most companies see it as a copy right. If you have friend working in this field, she...

most of the stuff I bought are made in China, that helps prevents me from red check book..

seems you have secondary and primary loop. If I pictured what you are seeing right. did the design provide you a flow diagram to follow?

this is airlock i normally see in my projects. corridor, airlock and lab. airlock has two doors, one to corridor and one to the lab. see if the lab is controled to be negative(-), the corridor is...

psu104, I am not sure what you are doing. When I am balancing an airlock, normally, we will count the doors connected with the airlock, rule of thumb, one door 100 cfm. If this is a positive airlock,...

I don't think this sensor is a mixing air stat. it is more likely to be discharge. the engineer might want to modulate the damper and the dx coil stage to get the desired discharge temp. Are there...

triton99: if gladstone is asking the flow rate, it is 3 gpm/ton,what I said 3 gallon/ton is for column. YOu have to have enough volumn in a chilled water system for the chiller control function...