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iceman007
01-09-2006, 07:57 PM
I wondered if any of my friends in the USA could give me a little assistance with a few technical questions relating to chilled water systems. I have had to do a test of 60 questions (technical ones) Most of them I've answered, but the last few I need some help with, because I don't do many chillers. Here goes.

1 What is likely to be the result if a forward curved centrifugal fan rotation is reversed, and what would you expect to increase proportionally as the forward curved fan speed increased ?

2 What methods should be used to correctly commission a water pump within the chiller hydraulics system ?

3 What is the minimum recommended water temp setpoint without the introduction of glycol ?

4 Where would you find a check valve on a refrigeration circuit and what is it's importance ? (I could only think of defrost systems and screw compressors)

5 Why do we use a 3 way bypass valve on a condenser water system ?

The only other question I didn't answer was something about what checks needed to be done if the water flow rate was reduced, but I'll have to answer that tomorrow.

Many Thanks for your help

cold in alberta
01-09-2006, 08:09 PM
you use a 3 way bypass valve to introduce warmer water to your condenser loop in the event your condenser water becomes to cold.

iceman007
01-09-2006, 08:38 PM
Thanks alot for that. I've been trying to find the answer for the last hour. Only 4 more to go.

thegoodhumorman
01-09-2006, 10:01 PM
#3 should be 33 deg I believe for freeze stat, not positive on other q?
I have put check valves in outlet of some condenser exchangers due to mispiping and logging (existing I swear) but will keep scratching head...

timjimbob
01-10-2006, 01:43 PM
Check valve is used in heat pumps. Now intergral with newer expansion valves and flowrator.

timjimbob
01-10-2006, 01:46 PM
Reversed blower wheel will blow with less velocity. Also, I think, double speed will increase HP by four times.

iceman007
01-10-2006, 02:10 PM
Thinking back, I remember putting check valves on reverse defrost systems, and sometimes downstream of the economiser if there was one on some chillers. I could really use a bit of help with the process to commission the pump. I guess it means balancing the flow, etc.

Thanks