Honeywell chilled water temperature controller

[Cofreth]

Hi,
I have a Honeywell Model ALBQ-NM87121-1958 chilled water temperature controller operating on a DunhamBush air-cooled chiller. As I suspect the chilled water sensor is out of calibration,compressor stops before desire temperature achieve and this controller already being obsolete by Honeywell. So how do I select an after market sensor for the replacement, thank you.

[Cofreth]

So I guess no one here can help on this problem?

[Dan]

I am not familiar with this control. Is this a thermistor sensor? If so, can you not offset the control temperature by the difference you see between the actual cut-out temperature and the set-point cut-out temperature? For example, if you see the control cutting out at 20 deg C and it actually cuts out at 30 deg C, can you not change the setpoint to 10 deg C to offset the actual so it is accurate for your purposes?

Also, if it is a thermistor, and you can tell us what the resistance measures at various temperatures including the desired cutout temperature, it is possible that we could see if a common thermistor would be worth a try.

Funny. I searched for the Honeywell model and the only useful web-page returned was your question here on Refrigeration-Engineer.com.:)

[US Iceman]

I can't help on the Honeywell control, but I do know Dunham-Bush used to use a multi-stage controller from Barber-Coleman that worked quite well.

[mambro_01]

hello Cofreth,
you should check by a multimiter wich kind of sensor is the one connected or better to ask Honeywell which sensor they use. Usually AC controller have a NTC sensor but in the market there're too version with different temp-res curves. If they give you the right model of sensor (e. Semitec 103AT2) you could replace it