Contractors Qs an As.pdf

400 Ton Chiller

Contractor Q’s and A’s

1. Can you send pictures of their existing system for reference? A picture has been attached

2. Is the 400T chiller capacity based on nominal sizing or does it need to provide 400 actual tons of cooling? If this is actual tonnage, what water conditions and ambient temperature is this performance based on? Nominal tons

3. The maximum MCA is listed as 790A. Is there any flexibility with this requirement?

No

4. Does the max MCA of 790A and MOP of 800A include the electrical for the pump or is that just for the chiller? Entire system – pump and chiller

5. Project requirements call for 4 compressors on 4 separate circuits. Would it be acceptable to provide a chiller with 4 compressors on 2 circuits? This would also be acceptable, as long as the circuits can still be throttled down 100 tons at a time, such that the portable chiller is capable of running at least in 100 ton increments, and as long as the configuration still allows for isolation of each compressor individually, so that 1 compressor being out of service could still be repaired while the other 3 run.

6. DDC Controls is listed under the accessory equipment section. Is the intent for the contractor to provide a supervisor controller that can communicate with the onboard chiller controller as well as control pumps/valves and read required sensors? Do these controls need specific capabilities to tie into building system building automation systems? Yes – a supervisory controller for the whole portable system is desired – chiller, pumps, any control valves, sensors. But it does not need to be able to tie into building systems.

7. What size trailer would be preferred? (48ft or 53ft) A smaller trailer would always be preferred if possible, as long as the equipment on it has appropriate clearance to work on and remove/replace as needed

8. Portable chillers are typically supplied with flow meters, though this was not specifically called out in the scope. Should we plan to add this to project requirements? A flow meter should be provided as part of the portable chiller system, yes.

9. A 40HP pump is called out, but it can’t achieve 1,200GPM @ 100TDH. Should we adjust to 50HP to meet the requirements? Yes, if an available 40 hp pump cannot meet the flow and pressure requirements, the flow and pressure requirements supercede and the system should increase to a 50 hp pump.

10. Will you accept alternate bids for chillers with 2 circuits (VFDs operated Screws)?

See answer to question 5.