Freeze Up Auto Or Manual In Chiller?

[abbasi]

Hi

can we use KP 59 thermostat DANFOSS MADE as freeze up thermostat mind u it is auto reset type in 70 HP water cooled water chiller
i dont agree and maintain that manual should be selected as it is last safety for compressor and autoreset type is not suited.
My question is can we use auto reset why and why not in both cases.

URGENT REPLY NEEDED

REGARDS

ENGR. ALI ABBASI

[afeef]

auto reset is not recomended for me , cause we must find the reason for freezing chiller, then we reset the thermostat to other cycle of operation
good day
afeef

[abbasi]

wat about people who are already using auto reset type thermostats

[afeef]

dear abbasi
you can check out the reason of freezing , like
1-do you have ethylene-glycol mixed with chilled water?
2-what is the evaporator tem. ? and the super heat degree
3-is the evaporator clean from scale and salt deposits
4-is the TEV working good?
5-is the air-handling units&fan coils clean?
6-may be the freez thermostat is faulty!
good luck

[rbartlett]

I have seen some manufacturers using auto reset freeze stats..

they usually have a delay timer in the control circuit which prevents short cycling.

however make sure you set it to trip out slightly higher than usual and a wide diff.

cheers

richard

[US Iceman]

I would only recommend the manual reset type.

With the automatic reset switches, the chiller can have repeated freeze and thaw cycles as the switch automatically resets. Even if the manufacturer provides an auto reset switch, I would change it to a manual reset.

You may sell a new evaporator after it freezes up and make some money, but this does not help the owner.

The manual switch trips out and shuts the chiller off until someone can find the fault. This is the best way in my opinion.

[abbasi]

hmmm
so the case is not to use auto reset freeze up thermostat it is needless to set auto freeze up on temp higher than desired coz differential will be low
Thanx for your suggestions

[jamcool]

I think manual resets on controls is the better way it forces some one to go to the unit and assumes that he or she will check unit and not just reset.

[ajmalparvez]

Hi Im ajmal Irecntly join refrigeration-engineer.com
I have problem fine filter alarm with maycom screw comprassor can I bypas FF

Thanks

ajmal

[US Iceman]

I have problem fine filter alarm with Mycom screw comprassor can I bypas FF?

NO, NO, NO...

Change the filter elements. And check the filter differential to make sure the differential is actually what the alarm is for.