HVAC guys to the courtesy phone please...

[FFT]

Quick question. This would apply to the field of aquaculture and temperature loss. I will try to keep the explanation to a minimum:

Is it possible for a refrigeration unit whose purpose is to chill water passing over a titanium coil to malfunction and reverse the cooling effect by means of heat?

Whereas, the t-stat has not been satisfied, the unit has malfunctioned, and the compressor is still running; possibly because a capacitor is at fault.

Basically, I have two 3 ton machines operation in line whose purpose is to chill seawater to 42 degrees. For over a month, when the machines normally not run at all, the t-stats are reading 47/48 degs. Suspicious of the t-stats, I have replaced them and the reading remain the same. After realizing one of the machines has malfunctioned I disconnected the power to it. Over nite, the machine that is operating normally has dropped temp to 42 deg and has satisfied the t-stat.

Mechanically, how could the malfunctioning machine create enough heat to heat the gases in the titanium coils and therefore heat the water?

 

[Rusty]

questions...ambient temperature consistent throughout? temperature of incoming sea water? is that consistent? you say they didn't run at all when not working properly, so perhaps wasnt heating, just not cooling? I have no idea what I am talking about but these seem like relevant to the discussion.

 

[dommie67]

a failed capacitor would prevent the compressor from running. If the system is a heat pump and the reversing valve failed to reverse for cooling mode, then the refrigerant flow would be reversed and the coil that normally cools the water would heat the water. If the system is just straight cooling then it could not add heat, it just wouldn't cool.

 

[Patrick]

a failed capacitor would prevent the compressor from running. If the system is a heat pump and the reversing valve failed to reverse for cooling mode, then the refrigerant flow would be reversed and the coil that normally cools the water would heat the water. If the system is just straight cooling then it could not add heat, it just wouldn't cool.

for straight cooling...

wouldn't it heat using the ambient temp on the compressor side??
(failed expansion valve)

if this was co-located with the high side of the other units, then the heat coming off those would be recycled in??

poking with a stick here....

 

[dommie67]

there wouldn't be enough heat to raise the water temp.

 

[FFT]

Ordered a new compressor for now, I'm just stumped as to what would bring the water temp up 5 degrees over what the system normally runs at. I'm sure there is something I've missed, but there is not a heat pump on this system. I'm running 16 machines at this point and have never seen this happen. My next guess is that an impeller on a water pump is creating excessive heat.

Thanks for the feedback.

 

[moray42]

This may not really apply in your situation, but in smaller systems running a single chiller I have seen heating if the unit continues to run after coolant has leaked out. With the units in tandem one with a blown compressor or out of coolant may be able to counteract the work of the other to the tune of a few degrees possibly. Really just a theory, and can't really account for why it seemed like they weren't running.