Chilled water GPM ?

[logmode]

Hi,
I need help on the job. I have three chiller barrels that are between and parallel to main return and supply chilled water (no brine). Each parallel loop has a proportional two way valve. One valve is closed and two are open. Main pump (only one pump) has a 5/8 load. Up at the top (the highest point of the loop) of the main return loop there is a hand butterfly valve then a large storage tank with W.M... This loop is an open loop, and it’s open at the tank. Ok here is the question: Why is it that when the hand butterfly valve is 40 % closed the GPM goes up? I know you need more input, sorry I am just looking for a place to start.
My thoughts: first I am going to check flow meter. I think GPM increases because supply psi increases causing trapped air to reduce.
Your thoughts on this will be greatly appreciated.
Thank you
Logmode

 

[KiwiMace]

Read the thread below. Note that it will not answer your question.

http://www.eng-tips.com/viewthread.cfm?qid=328800

 

[logmode]

Hello,
thank you for your response.
I do not understand why you would want me to read something that will not answer my question.
I have read what you asked of me to read. trashcanman and chasBean gave a great response and I agree with them.
If I gave an answer to Nicole, it would have been: I think Your GPM has increased with pressure increase, and if so why? (Sounds like what I am asking about)
Is that why you wanted me to read this?
or
Then there TTFN basically read the rules. Was that your point?
or
(nicole10g (Electrical) However, I am interested to know if there is no expansion tank connected (literally) but with the bypass valve open, what untoward impact will it happen to the aircon system that I should take note? ) She received no answer, ignored! I would guess the reason she was ignored is because they felt it would take too much time and they needed more facts. Is this the reason why you wanted me to read that post?

Where am I to go with this?

Thank you
Logmode

 

[ChasBean1]

Logmode, although you are articulate, the system you describe requires a sketch to go with your post. I got lost in your description as to what the issues are. For example, gpm goes up where? Can you provide a schematic of the system?

Best, CB

 

[willard3]

I'm with chasbean, I don't understand your problem from what you've written.
I don't think you understand the problem, either and should get an Engineer to give you some help.

 

[KiwiMace]

I linked you to the other post because you were both sharing unusual anecdotes about profound system effects based on a minor change at the expansion tank. These kinds of questions are akin to calling up the Tappet bros on Cartalk and asking why your headlights turn on when you indicate left. The observations may be happening, and they may even be related, but if you ask an open forum what the cause of the problem might be, expect at best a generic discussion on the utility of expansion tanks and the benefits of chilled water flow.

 

[Shophound]

Does the chiller unload 10% every time you add water directly to the loop, or was it only a one time observation?

 

[logmode]

CB only one question. Why GPM goes up (increases) when return butterfly starts closing? GPM should go down.

 

[logmode]

the diagram it did not work the first time.

 

[logmode]

You asked for a diagram, you have one. You say you’re lost, it is only one question. At least say something.

 

[DRWeig]

Have a little patience, logmode. Your last post was way past my bed time, and I'm sure the same applies to others.

Best to you,

Goober Dave

Haven't see the forum policies? Do so now: Forum Policies

 

[317069]

as I understand from your post:
- three parallel chillers, only two of them are in service at any time.
- these chillers feed a main supply line
- this line end up with valve and storag tank, ( I didn't understand what is W.M ...?
- you have one pump only in this system, but Also i didn't understand what is" pump has 5/8 load"?
- you have a return pipe connects the storag tank with pump suction.
- you observed that when the valve before the tank is closin the GPM increase.the questions are:
- at which point did you meeaure the GPM and how?
- is this tank is open to the air

 

[logmode]

Hello 3-9,
Thx for the thought.


- these chillers feed a main supply line

Yes

- this line end up with valve and storag tank, ( I didn't understand what is W.M ...?

Yes this return line. W.M. is water make up.

- you have one pump only in this system, but Also i didn't understand what is" pump has 5/8 load"?

(a) Yes one pump

(b) When a pump is running there is a load on it. This pump has a 5/8 or the correct way is to say 62.5% load on it.

- you have a return pipe connects the storag tank with pump suction.

Yes

- you observed that when the valve before the tank is closin the GPM increase.the questions are:
- at which point did you meeaure the GPM and how?

(a) First A/H on the loop. This A/H is the closes to the chiller.

(b)The first A/H on the loop has a G.P.M. gauge.

- is this tank is open to the air

Yes

Thank you
logmode






He who is often reproved, yet stiffens his neck, will suddenly be broken beyond healing.

 

[317069]

- "When a pump is running there is a load on it. This pump has a 5/8 or the correct way is to say 62.5% load on it".
what about the 37.5% of pumping load from where does it come?

- you are checking the flow at a point which is not on the main pipe, it is on the A/H branch pipe, so if the flow increase at this branch it would be decrease at another branch because when you close the valve you are changing the system resistance
you need to measure the flow at the pump discharge to say it is increasing or decreasing.

- your tank has a make up water, which is not chilled water I guess, that tell this is a kind of process, then you say this system is connected A/H which is HVAC, if A/H means an air handler, what kind of system do you have?

 

[ChasBean1]

I just re-read prior posts and I'm at a stoppage point. With the diagram you sent, if flow increases with closing the return valve it means the flow meter is not correct.

 

[logmode]

I can here because I was looking for an answer to something that happened that does not make sense. It is a ball with a spring. When flow increases the ball over comes the spring moving to a higher number. Maybe the number is not a correct value but the spring compression is definitely an indication of more flow. I am asking you to think that it is true and what could cause it.
logmode

 

[IRstuff]

Is this for school?

TTFN
faq731-376

 

[logmode]

If you read the beginning it will answer your question.
thank you.

 

[317069]

why are you agressive, he is asking a question, what ever you post in your first question doesn't say what kind of system is this?
it could be a school or anything or even a homework, if you don't know how to respect people here so don't ask and save your time.

 

[logmode]

IRstuff I did not mean or intend to offend you in any way. I thought that I explained myself well in the beginning of this thread. (I need help on the job) But as 317069 has pointed out of my error. I am so sorry, can you please forgive me. No I am not in school, hugs and kisses.

moreBy the way a answer of some kind or even a thought of a possibility would be greatly appreciative.

hugmode