Low Pressure

[westerndf]

So I have a J&M Fluid Dynamic chiller that was new in August. Right of the truck there was issues and it was determined that the HX had a leak due to there being freon in the reservoir tank. SOO the HX got changed out, and once it was sent back to the factory for testing it didn't fail so no warranty coverage but the unit functioned perfect until this weekend. Our temps dropped below freezing outside and I was told this unit was set for outside cold weather usage. I am so pissed with this machine. We paid 13K for it and it didnt work, then had to eat another 7K to get it fixed do to it no being covered under warranty. Now the unit is saying low pressure and has 0 suction on the read out. I am so done with this new unit that is only 3 months old. Any idea why it would have low pressure once it gets cold out? Will this continue all winter? IM F#@King done with this unit. I have a call into my mech tech Just hope it not another big bill

[gvh_Dan]

Not to make you feel worse but when they sold it to you did they say anything about cold weather operation? I'm not familiar with "Fluid Dynamic" but some chillers are only built to operate down to an ambient temperatures above freezing and most don't go much below 0F. Its because most chillers, especially the smaller air cooled units, are made for the Air Conditioning world and not process cooling. in the A/C world, they are switched off in the winter.

Assuming yours was built for this service, there may be a switch or something that needs to be flipped. The "low Pressure" probably indicates a low pressure in the condenser (outdoor heat rejection portion) due to the cold temperatures. Normally there would be a method to modulate the rpm of the fan motor in response to outdoor ambient temperature to keep the chiller's head pressure up.

Or it could be low suction because the refrigerant is gone.

Whatever it is, I hope it is easy and cheap to fix.