comtrol

[bullit]

I have recently had problems with a alarm on a comtrol system. The alarm is a open low liquid level. I graphed the level and after a defrost period and in cold weather it will just breifly get to 0% and then rise again to about 40-60% so when it gets to 0 no matter how breifly, it alarms as a open sensor. I could not find a place to add a delay to this alarm. this is on a med. temp hussmann rack.
anyone run into this problem, any way to add a 15 min. delay? this particular comtroll system has 3 4ks and one 6k. I am not sure as to the version # of the software?

[smilies]

Do you have the EZSet II on your laptop?

[bullit]

no i do not , we do have it believe on the shops laptop.

[Freezeking2000]

I think what is happening is the level is going over 80% and causing the liquid level senson to send a 6 vdc signal to the comtrol. You need 5 volt a center tap diod(radio shack)installed to prevent the 6 vdc reading from causing the sensor fault. (The diod just connects between the sensor wires) The level sensor is 6 volts and the controller is 5 volts. With the diod the level will not go above 80% but it wont alarm out. I have fixed a few this way! * for less than $5.00 *

[mccool]

Hi bullit, I have noticed that your temps in Portland have taken a dip from the norm, likely enough to cause migration to the "B" side of the MT condenser and the subsequent alarms. Guessing just a result of the unusual low temps or time for a leak check.

[mccool]

Originally posted by Freezeking2000
I think what is happening is the level is going over 80% and causing the liquid level senson to send a 6 vdc signal to the comtrol. You need 5 volt a center tap diod(radio shack)installed to prevent the 6 vdc reading from causing the sensor fault. (The diod just connects between the sensor wires) The level sensor is 6 volts and the controller is 5 volts. With the diod the level will not go above 80% but it wont alarm out. I have fixed a few this way! * for less than $5.00 *

Seen that a lot also Freeze, but have not worked with Comtrol for almost 2 years, bullits problem seems to be the opposite, "alarm on low level".

Sounds like a good solution though to the majority of nuisance Comtrol alarms, we were always getting alarms from HVAC when the signal exceeded 5 volts. Interrmittent high reciever alarms though may require a followup check on the master liquid line solenoid differential setting, it could be causing wide fluctuations in the reciever level if not set up properly.

[bullit]

thanks for the suggestions ,very much appreciated

[mspanky]

I don't believe you can delay any open sensor alarms, only disable ALL together. I agree that it is time to leak check and verify that the holdback valve it set and operating properly.

Mccool, I don't know if a Master LLS is relevant as it is a med temp rack.

A zener diode is what would be used to limit the signal to 5Vdc, but is not quite as easy to stop it from reaching 0Vdc.

[condenseddave]

Is it an analog or digital alarm?

[bullit]

this would be a anolog alarm I graph the liguid level and as i said it will be between 40-60% most of the time sometimes jumping as high as 70% but it alarms at 0% as a open sensor it gets to 0 after a defrost period i can pinpoint the time of the alarm and the liguid level at that same time. I will be going back to this location wed. and will look into some of these suggestions at that time.

thanks again for all the help.

[Freezeking2000]

Originally posted by mspanky
I don't believe you can delay any open sensor alarms, only disable ALL together. I agree that it is time to leak check and verify that the holdback valve it set and operating properly.

Mccool, I don't know if a Master LLS is relevant as it is a med temp rack.

A zener diode is what would be used to limit the signal to 5Vdc, but is not quite as easy to stop it from reaching 0Vdc.

I have been fooled in the past.i am sure the level is really going up post defrost and causing it to go above 70-80 % and causing the sensor to fault. It is a digital sensor. Get the brand of the sensor and call com-trol...if you can get any one with a brain on the phone.