Powers pneumatic panels

[GUDTEK]

Hi guys, hoping I can get some old-school wisdom on this one...
I just picked up an account utilizing pneumatic thermostats and panels. All controls are manufactured by Powers and are older than dirt. Each air handler has a re-heat, heat, and cool 3 way valve. Each A/H has one pneumatic stat going to an old Powers pneumatic panel (163-0160, model 2C7).
Heat valves are 3-8 PSI, Cool valves are 8-13 PSI. I need to do some calibration, and believe I can sort through calibration of the stats by setting neutral at 8 PSI.
My real problem is calibrating the old Powers panels. They have two long indicator needles on them, a black one for actual temperature, then a red one with a circle on the end of it, both are operated by brass bellows. I think that the red needle is indicating the thermostat input - the greater the scale difference between the red needle and black (actual temp), the greater (or lesser) the output to the appropriate valves. These panels do have adjustment for a manual 'zeroing' and for prop band.

Anybody know the panels that I'm talking about here? If I calibrate the thermostats, then set all stats to match actual temp, should the red and black needles on these panels then be reading the same?

[printer2]

Hi guys, hoping I can get some old-school wisdom on this one...
I just picked up an account utilizing pneumatic thermostats and panels. All controls are manufactured by Powers and are older than dirt. Each air handler has a re-heat, heat, and cool 3 way valve. Each A/H has one pneumatic stat going to an old Powers pneumatic panel (163-0160, model 2C7).
Heat valves are 3-8 PSI, Cool valves are 8-13 PSI. I need to do some calibration, and believe I can sort through calibration of the stats by setting neutral at 8 PSI.
My real problem is calibrating the old Powers panels. They have two long indicator needles on them, a black one for actual temperature, then a red one with a circle on the end of it, both are operated by brass bellows. I think that the red needle is indicating the thermostat input - the greater the scale difference between the red needle and black (actual temp), the greater (or lesser) the output to the appropriate valves. These panels do have adjustment for a manual 'zeroing' and for prop band.

Anybody know the panels that I'm talking about here? If I calibrate the thermostats, then set all stats to match actual temp, should the red and black needles on these panels then be reading the same?

Not familiar with the Powers but you seem to have the right idea to calibrate them. Can't see anyone designing a pneumatic control that did not output the center of the range when the setpoint and process variable (temperature in this case) is at the same point.

Basically you have span/throttling range/gain, which ever word you are comfortable with, and offset to play with. Your A/H are set up for 8 psi so I would calibrate for that point with both needles reading the same.

[statman]

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[statman]

Powers made a number of versions of these and we used to rebuild a lot of them up to about 10 years ago. We still see them once every now and then.The good news is they were excellent, the bad is that the parts are now almost non-existent. You should view this as a pneumatic sub-master controller. It should have a thermal bulb attached and the bulb temperature range is capable of mimicking a 100 or 200 degree transmitter. Calibration is tricky and these mechanisms are fragile for such a tough workhorse. So the best thing is for me to send a cut sheet to you. In most normal operations, the red and black needles will have an (adjustable) offset. Contact me and I will fax you info.
Statman
EPRI
800-356-3774 X 100
www.eprinc.net

[GUDTEK]

I managed to sucessfully get these things calibrated today! Unbelievable how far off they were to begin, but now they surpisingly seem to do their jobs pretty well still.
Set all stats to actual temps, used digital thermometer and manual adjustment to dial in temp sensor indicators, then used sub-master adjustments to calibrate valve outputs to 8PSI when needles lined up. Black needle swings right of red = PSI increase. Black swings left of red = PSI drop. Neat little setups, first one I have seen.

Statman, I would still like to take you up on your offer on the cut sheets and will contact you privately, that is a huge resource that I did not anticipate being available, and would use for future service at this facility!

[Control Man]

Likely the POWERS series 200 Temperature Regulator

Agood control was originally an industrial grade process control adapted to HVAC applications.

Have some on jobs from the late 50's that still work great, bit tricky to setup and calibrate , they have an A few adjustments that are not your regular adjustments and you can get in a mess real fast.


Proportional band is only 0 -35% , factory set at 30%. You have manual reset adjustment as well on these controllers , They operate best at 20 PSI main air supply

[fms2k]

try this company:

www.neccdelivers.com

they are a siemens/powers distributor
and have detailed "cut" sheets on all
old powers controls going back some
30 years.

they will provide you all the information
you need at no charge. they also have
people there who actually know how all
this old pneumatic stuff works and can
walk you thru it.