Question For Carrier Gurus

[drivewizard]

Went to a job site today to startup/calibrate a new Trane Refrig monitor.
The Customer had installed a new Carrier water cooled chiller (R-134a) and monitor. I believe the Chiller was a HXM.....?(not sure about M#) Had 2 small screws, anyway, my job was not to work on the chiller as the Carrier rep had already done his thing.

I was looking at the cond water piping including 3-way valve, what I saw doesn't appear correct. But, maybe this is the way Carrier does it???
The customer said the engineer wanted it this way and Carrier rep checked and said OK.

When the by-pass valve is closed there is full flow thru cond and over tower. This part is correct.

But, when the by-pass valve is in full by-pass there is no (0) flow thru cond barrell, but there is still full flow across tower cells.
The cond does not have a flow switch either.
This seems ass backwards, what a wast of energy and possible fouled tubes. Why continue to cool cond water when it is to cold to begin with?

Is this a new Carrier scheme? Or did the owner/customer screw up the piping. It wasn't really my place to push the issue as it is not our chiller, but they swore thats what the engineer wanted.
Doesn't seem very energy efficient to me.:confused::confused:

[lynn comstock]

If this is a modulating valve, when the water is cold, the valve will bypass some water around the condenser to reduce flow through the condenser (responding to head pressure?) in order to maintain head pressure in colder weather.

[freonrick]

I have a pair of McQuay centrifugals set up the same way. I do not like it, never did and never will.

[jackt]

Just curious, what they monitoring to control the valve? Are they using condenser water temperature to modulate the valve, head pressure or what? Doesn't make much sense to me. I've used three-way vales to reduce the amount of water going out to the towers but not to the condenser. Even though I live in an hot southern environment, I still get cold winter days when I need to reduce my water flow to the towers. One lessen I learned many many years ago, because a engineer designed it that way doesn't make it the correct way.

[Dallas Duster]

Went to a job site today to startup/calibrate a new Trane Refrig monitor.
The Customer had installed a new Carrier water cooled chiller (R-134a) and monitor. I believe the Chiller was a HXM.....?(not sure about M#) Had 2 small screws, anyway, my job was not to work on the chiller as the Carrier rep had already done his thing.

I was looking at the cond water piping including 3-way valve, what I saw doesn't appear correct. But, maybe this is the way Carrier does it???
The customer said the engineer wanted it this way and Carrier rep checked and said OK.

When the by-pass valve is closed there is full flow thru cond and over tower. This part is correct.

But, when the by-pass valve is in full by-pass there is no (0) flow thru cond barrell, but there is still full flow across tower cells.
The cond does not have a flow switch either.
This seems ass backwards, what a wast of energy and possible fouled tubes. Why continue to cool cond water when it is to cold to begin with?

Is this a new Carrier scheme? Or did the owner/customer screw up the piping. It wasn't really my place to push the issue as it is not our chiller, but they swore thats what the engineer wanted.
Doesn't seem very energy efficient to me.:confused::confused:

Where are you from what kind of climate do you have in winter time? Also if the chillers were controlling the vales which I doubt in this case there would be a minimum of 20% closed in the software.

[chiller rob]

maybe they are leaving the cond water at full flow as they may want to install a plate and frame for free cooling in the future...

also min flow thru a tower will scale it up for sure...

alot easyier to clean a cond barrol than change fill media...

just an idea...

[acjourneyman]

Look in the Trane RTHC book and it is a recommended bypass method in there also, the same with the other screws. I agree that it is backwards but even Trane does the same thing.

[drivewizard]

1. I don't know what they are using to control the valve. Didn't get that far into it.
2. I am in the NW part of Oregon, Summer nights usually in the low 50's and can get into the 90's during the day.
3. I don't know about future plans for a plate frame HX, but I kinda doubt they thought that far ahead.
I never thought about the Towers possibly scaling up faster with low flow, but then again I have never seen an Engineer concerned with maintenance or service issues and given them any consideration in his design. Usually it is all about energy savings and initial cost.
4. The Trane Screws I have started sometimes have a 2 way Reg valve but with a min flow, to make flow switch. Then a by-pass is not used.
If a by-pass is used it by-passes the tower, not the cond, until the water temp is slowly raised enough to modulate to full flow thru cond and tower.