UCP2 chilled water setpoint

[ChillerWisperer]

Anyone ever have a problem with the chilled water setpoint pot on a ucp1 going screwy and drifting off setpoint? I have one under contract that seems to be doing it, but I haven't caught it yet. The plant operator says he has seen the setpoint up as high as 60 when scrolling through the menu and then by just touching the knob, it drops right back to 45 and the chiller starts. Never any diagnostic, it's just the ucp1 "seeing" no cooling required and off cycling. Also one time, it apparently crashed when he switched from hold to auto on the vane control. Don't know if that's related, it may have been coincidental that the setpoint happened to drift passed the diff to stop setpoint at that moment. When I look at it, it will never do it. I can raise and lower setpoint and the display shows it being exactly where it should be for the knob position. I'm thinking just some contact cleaner might help it out. Any thoughts? When this starts to happen, is it just a matter of time before having to replace the 1U3 mod?
I've had to replace them when they fail internally before, just never seen this type of failure.

[klove]

There's a knob on a UCP2?

[ChillerWisperer]

There's a knob on a UCP2?

ucp2...did I say ucp2

Yep...sorry. I meant ucp1.

Had ucp2 on the brain because I was thinking of another machine I was working on today.

[txhvac]

UCP695. Assuming the sensor is good, try doing a power supply check out 1U2, verify 1U3 ops. CVHE-SB-22A should help. Hope this can help.

[ChillerWisperer]

UCP695. Assuming the sensor is good, try doing a power supply check out 1U2, verify 1U3 ops. CVHE-SB-22A should help. Hope this can help.

Sensor appears to be good. Reading is spot on in ice water. I just pulled up SB-22 and was reading through it.

[drivewizard]

Sounds like a dirty POT like Graham said.
I have had pretty good luck getting them to work properly by turning them rapidly from limit to limit about 8-10 times.
Usually works. There is likey some lint or dust built up in the POT and that is all it takes to clear it.
Cheaper than replacing the whole Mod-.

[Healey Nut]

Sounds like a dirty pot to me . How do you plan to replace the 1U3 mod after December 31st 09??? Unless you have a spare already .

[ChillerWisperer]

Sounds like a dirty pot to me . How do you plan to replace the 1U3 mod after December 31st 09??? Unless you have a spare already .

That's why I was wondering if I should just go ahead and replace it while it is still available.

[triggerhappy]

That's why I was wondering if I should just go ahead and replace it while it is still available.

Hey whisper I went to one doing the exact same thing to day.

Ordered an new 1U3 board. As of this afternoon Trane had 5 in stock.

[chiller mekanik]

MCS controls can custom make you a panel with a graphic display for far le$$ than you probably would think.

[MKnyc]

how much?

[triggerhappy]

MCS controls can custom make you a panel with a graphic display for far le$$ than you probably would think.

As far as I know Trane supports the stuff they sell for 20 years or more.

Are you sure that the company that you speak of will do the same.

I checked out their website and they have only been in business since 1994.
The question I have is will they still be around and supporting their flavor of the week in 20 years.

[Healey Nut]

Theres a complete UCP1 control on e-bay for sale . Brand new

[Randy S.]

One trick I've seen operators do with a UCP2 is to think, by enabling a temperature reset,
that they are resetting the fault holding the chiller out. Then I find it sitting there not loading up.

Haven't seen one make changes on its own, though.

[ChillerWisperer]

One trick I've seen operators do with a UCP2 is to think, by enabling a temperature reset,
that they are resetting the fault holding the chiller out. Then I find it sitting there not loading up.

Haven't seen one make changes on its own, though.

It's a ucp1...sorry. See my earlier post correcting it.

[NWMech]

Also one time, it apparently crashed when he switched from hold to auto on the vane control.

Why is an operator messing with the manual vane control anyway? There's a problem all in its own! I love trying to figure something out based on information from a maintenance guy, but it never happens when you're there.

[ChillerWisperer]

Why is an operator messing with the manual vane control anyway? There's a problem all in its own! I love trying to figure something out based on information from a maintenance guy, but it never happens when you're there.

He was logging it and one of the readings he logs is evap ref temp, which can only be accessed through the servicemans menu. He's been around this machine since it was installed in '87, and is very familiar with it so I don't have a problem with him doing that. Most operators...well, I'd have to agree with you there.

[Randy S.]

Duhhhhh. I need to pay attention.....

[ChillerWisperer]

Spritzed it with contact cleaner and ran it clockwise and counter-clockwise to the stops a few times and it seems to have done the trick so far. No funny readings from it in a day and a half.

[chiller rob]

we had one doing the same thing the other day...

the control respose was not holding its value...

we set it at 100 and then went back and looked at it later and it was back to 1.

the pot cycle trick worked on that one...

i would not buy a ucp1 on ebay...
personnally i think that is the worst panel they made... it is very limited...

ucp2 and up i like very much...

Chiller Rob