Minimum Pump Flow in PSI?

[ZeroTolerance]

What is the minimum PSI (Chilled Water and Condenser Water) a Trane CVHE570 Chiller can operate at? I can't seem to find it in the manual.

[Six]

Did they install the VFDs ?

[ZeroTolerance]

No, I am trying to figure out if I can run all three of our big chillers (two 600's and an 800) at the same time without cavitating the pump(s).

I know our tower has the capacity, but I am wondering if our pipe configuration in the plant can handle it.

Yesterday, we had to run both our 600ton chillers and our little 125ton pony to keep the building. The 800ton is from 1985 and we question its reliability, the reason why we always run our two 600's instead.

I do know, that we cannot run our 125ton and 800ton chiller at the same time, as it has cavitated our 125ton in the past. Thanks to the genius engineers who piped it in. (MORONS)

[R123]

What is the minimum PSI (Chilled Water and Condenser Water) a Trane CVHE570 Chiller can operate at? I can't seem to find it in the manual.

What do you mean? Minimum differential water pressure?

[Healey Nut]

What is the minimum PSI (Chilled Water and Condenser Water) a Trane CVHE570 Chiller can operate at? I can't seem to find it in the manual.

You wont find it in any manual .
All Trane chillers are design build and all unique . You need the original design spec sheet for the chiller . You will need to get it from Trane and they will want the serial # to find the info .

[ZeroTolerance]

K, Thanks Healey

[jayguy]

...I do know, that we cannot run our 125ton and 800ton chiller at the same time, as it has cavitated our 125ton in the past. Thanks to the genius engineers who piped it in. (MORONS)

are these chillers in parallel? i do not think that you are actually cavitating the chiller...you probably do not have enough flow through the little chiller since the big chiller has so little pressure drop, most of the water will want it to go through the big chiller instead of the little chiller.

i had a similar (if this is what you have) situation before with a remote barrel RTAA100 and a RTHD (250 nominal ton). VFD's on the evaporator pumps...it was a variable primary pumping system. RTAA running balls out at 360 gpm (maximum allowed) at 13.5 psid....not enough chilled water....so, open the valve to the 250 ton chiller....minimum gpm for the 250 ton chiller is 375 gpm at 1.1 psid....see a problem? the pump speeds up to 1.1 psid across the RTHD providing 375 gpm through it, but 1.1 psid across the 100 ton chiller is 89 gpm. so the 100 ton chiller goes from 360 gpm to 89 gpm in the time span of an isolation valve opening....why can't the chiller stay online says the engineer? they don't make'm like they used to i guess! dumb salesmen...uh, i mean...engineers.

[CraziFuzzy]

Those old trane chillers are designed for a fixed condenser and evaporator flow. They may ver well operate outside that fixed point, but it is not by design. As mentioned though, the GPM required will be recorded with the cutsheet and startup worksheet. If you don't have that, trane SHOULD still retain that information.

I'm not really sure what you are asking for in regards to PSI though. The chiller doesn't really care about the water pressure, just temperature and flow.

[ZeroTolerance]

Well, if I have less flow, my PSI would drop compared to normal operating conditions.

The PSI gauge is all I have to tell me if I'm getting flow or not into my chiller.

That is correct Jayguy, the 800-ton is "hogging" all the water due to the way it's piped. I'll take a picture of the pipe config and post it, so you can get a better understanding of what I am talking about.

[ZeroTolerance]

Can anyone see the problem here? lol

[Healey Nut]

Can anyone see the problem here? lol

Ahhhhhhhhhhh run for your lives its a piping Triffid !!!!!!!!!!!!!!!!

But seriously , guess whoever designed/piped it never heard of "path of least resistance" ??

[CraziFuzzy]

There should be a balance valve on that 800 ton condenser that can be throttled to limit the flow through the chiller. The aforementioned start-up data should list the D/P for design flow of the heat exchanger, so you will have something to target. Of course the piping isn't ideal, but the length of pipe where the two are combined is very short, and shouldn't result in a catastrophic amount of pressure drop.

[jayguy]

do you have a sealed system on the condenser water side or is it open at the tower? and i think that you mean PSID and not just PSI...right?