McQuay MicroTech II

[duke of earl]

Does anyone know what DC voltage is for temperature sensors on MicroTech controller-Typical is 0-5 for most. I had one this week only develop 3.78vdc with the sensor disconnected. The chiller thought it was making 44 degree water when in reality it was really making 60 degree water. I love the sensor on the brazed plate evaporator on the AGZ product.

[Need2Chill]

Analog Inputs
# Description Signal Source Range
1 Reset of Leaving Water Temperature 4-20 mA Current 0 to10 degrees
60°F max inlet
2 Evaporator Refrigerant Pressure 0.5 to 4.5 VDC (NOTE 1) 0 to 132 psi
3 Condenser Refrigerant Pressure 0.5 to 4.5 VDC (NOTE 1) 3.6 to 410 psi
4 Leaving Evaporator Water Temperature Thermister (10k at 77°F, 25°C) -58 to 212°F
5 Outside Ambient Temperature Thermister (10k at 77°F, 25°C) -58 to 212°F
NOTE 1: Value at the converter board input. Value at the converter board output is 0.1 VDC – 0.9 VDC.

[Octopus]

Does anyone know what DC voltage is for temperature sensors on MicroTech controller-Typical is 0-5 for most. I had one this week only develop 3.78vdc with the sensor disconnected. The chiller thought it was making 44 degree water when in reality it was really making 60 degree water. I love the sensor on the brazed plate evaporator on the AGZ product.

Is it the sensor that is like bulb with some duct tape holding it to the plate?

[duke of earl]

Anyone?

[Need2Chill]

The MT II uses 10K NTC thermistors. I saw the voltage reference and quoted you the pressure transducers in the last post. I attached the resistance scale for your use.

[duke of earl]

Need2Chill,

I need to know what dc voltage is used for the LWT sensor. The data you provided did not include that information. Thanks for the chart.

[duke of earl]

I wish McQuay would include the dc values next to the temp/resistance on that chart like most everyone else does.

[milkyway]

I wish McQuay would include the dc values next to the temp/resistance on that chart like most everyone else does.

yeah., from what i understand , mcquay is not too helpful with their technical info on their machines

[klove]

yeah., from what i understand , mcquay is not too helpful with their technical info on their machines

They're no different than most others. You almost need to have worked for one of the factory service groups to understand how much info is out there, but not available to private service organizations. It really is a cryin' shame that they all want to sell parts for 5 times what they're worth, but then refuse to support the folks that put food on their table by buying them.

[txhvac]

Did you call your local McQuay office? I'd agree they may not be too helpful, have you tried calling Staunton, VA? I've gotten some good support from some of their guys there.

[polopolo]

Hi, Would you know the 10 digit super user password ? Paul