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David PS
21-07-2003, 12:46 PM
We were asked to look at a chiller with control problems.

It is a stand alone unit which serves two ahu. The unit operates when a set of external volt free contacts complete a circuit.

Chilling to the ahu is controlled by the BMS and mechanical valves.

The external contacts are controlled via a small pressurization unit, which consists of a header tank, pump and high & low pressure switches.

The pressurization unit pumps is connected via water piping to the chilled water ring.

Can anyone shed any light as to how the control logic is meant to work.

Thanks

David

David PS
21-07-2003, 07:57 PM
The pressurization unit mainly, leading on to the chiller.

mgtet
29-08-2006, 09:14 PM
What sort of control problems are you getting? I can't see the pressurization unit sending the enable signal though although it might be an interlock. I would suggest attending site with the controls company to determine which is at fault, the chiller or the controls.

Peter_1
29-08-2006, 09:29 PM
...The external contacts are controlled via a small pressurization unit, which consists of a header tank, pump and high & low pressure switches.
The pressurization unit pumps is connected via water piping to the chilled water ring.

This needs a small schematic because I don't understand your set-up.
I think others think the same and if the question is already difficult to understand, then the possible answer will also be wrong or direct you in the wrong direction.

Brian_UK
29-08-2006, 11:14 PM
Have to say folks that we have missed this post somewhat.

As it is over three years old I would imagine that he has resolved the matter by now ;)