No Freeze Stat

[jimp]

Why would a manufacturer depend on the temperature thermistor that cycles the chiller for freeze protection? Yesterday I went out on a MR chiller and found the Glycol running at 2F, everything was iced up. It had locked up the Cold head compressor and one of the LCC Gradient pumps was locked up.

The discharge Glycol/water thermistor went bad and was reading 80F, full speed head at 2F.


Seems like a cheap old Penn control would solve the problem, but its probaly cost $40.

[Octopus]

GE machine? The one with the chinese writing all over it.... Well wait till you see how much that pump is.

[zw17]

A better question is why didn't the software program recognize the LWT 78*F higher than the EWT and shut the machine down?

[jimp]

GE machine? The one with the chinese writing all over it.... Well wait till you see how much that pump is.

I have a supplier that I buy from at 1/3 the cost of the OEM.

[jimp]

A better question is why didn't the software program recognize the LWT 78*F higher than the EWT and shut the machine down?

Only item in the software that recognizes high RWT brings on the second compressor.

[zw17]

Only item in the software that recognizes high RWT brings on the second compressor.

Sounds like garbage.

Does the manufacture require field provided freeze protection?

[R123]

A better question is why didn't the software program recognize the LWT 78*F higher than the EWT and shut the machine down?

Or why didn't the software recognize such a high approach?

Also, sn't there a low evap refrigerant temp setpoint?

[milkyway]

that is what i am thinking, i would look at a low EWT setpoint,. i would think it should be set up around 35., if this machine has this option,.
if not i would install one., but this machine with factory controls should have some sort of protection.,

[jimp]

Sounds like garbage.

Does the manufacture require field provided freeze protection?

I have complained to the factory about no protection, but it seems the engineers are clueless. They do require a 50/50 mix, which saved the chiller plates. But I bet the pumps were pumping Slush at 2F.

Field provided no, because the thermistor will shut it down.

[R123]

I've seen Trane machines with CH530 controls have leaving chilled water temp sensors fail reading high and the machine would limit on low evap refrigerant temp. Also, they will trip when the leaving temp reads higher than entering temp. The latest software will also cut out on high approach. Kinda triple redundant on freeze protection.

[milkyway]

I've seen Trane machines with CH530 controls have leaving chilled water temp sensors fail reading high and the machine would limit on low evap refrigerant temp. Also, they will trip when the leaving temp reads higher than entering temp. The latest software will also cut out on high approach. Kinda triple redundant on freeze protection.

That's a great setup for protection,
Triple safety, nice