Trane 60 ton chiller - low flow issues

[Nuclrchiller]

I would troubleshoot the unit myself, if ya'll get called in. Their explanation of the problem, and of their diagnosis, might be "slanted" to back up their belief. It's just human nature to look for agreement. If they took a wrong turn in their troubleshooting, you don't want to follow them down that path.

[dlove]

I don't understand, why do they "think its flow" perform a flow test would answer that. How is the chemical treatment there? just because they think they have a great program in place it don't take but one day to foul the tubes. and if a week went by the tubes could be really fouled.

As soon as somebody said flow i would have done test. If the test come back good, Chemicals next.

[KnewYork]

...it don't take but one day to foul the tubes. and if a week went by the tubes could be really fouled.

Really? A day? Let's be realistic here. It'd take a lot longer than a day to foul an evaporator (closed loop). Even a condenser w/o treatment won't foul to the point of reduced flow in a day, nor a week.

[mikeacman]

FYI - it is shell & tube (liquid in shell, refrig. in tubes) which is probably why they were told that it wasn't easy to clean. Check this link - http://local.alfalaval.com/en-us/key...20-%206.10.pdf

They claim that the water is treated and routinely tested to meet standards,

Ive heard that one before , matter a fact I heard that line today ...

I call BS

If it's fouled that is ...I say troubleshoot it yourself ...you may come to a different conclusion ,,,

[dlove]

Really? A day? Let's be realistic here. It'd take a lot longer than a day to foul an evaporator (closed loop). Even a condenser w/o treatment won't foul to the point of reduced flow in a day, nor a week.

go back to the original post "they think" its flow. My assumption is and maybe the OP can clarify, is they are having problems with cooling or load demand. And yes fouling of the tube can happen real fast when you have hard water. I seen it happen, not enough to restrict flow but enough to effect the approach and load demand.

[KnewYork]

And yes fouling of the tube can happen real fast when you have hard water. I seen it happen, not enough to restrict flow but enough to effect the approach and load demand.

First of all, the OP didn't even know the evaporator was DX. If you want to hold on to the notion that an evaporator bundle (whether DX or flooded) can foul "real fast" because it doesn't have water treatment, then I guess we'll have to agree to disagree. I'm not sure what "real fast" is from a quantitative standpoint, but your original statement was a day or week. Is "real fast" more or less than a week?

I am a proponent of fact based decision making. I do not believe you have any quantiative facts to back up your statement with regard to fouling. To shift the focus to performance rather than flow is also not based in fact or the OP's original statements.

[dlove]

We have looked at a Trane 60 ton chiller that possibly has multiple problems and we are working with the factory maintenance people who think that the low flow issues are due to the chiller barrel tubing being restricted. Are hands are somewhat tied due to the fact that the maintenance people want to do as much as they can do. We asked a lot of questions and made some suggestions and then didn't hear back. Recently I ran into one of the powers that be and he said that "Trane" told them that they could not clean the chiller barrel.
Has anyone ever heard of this? Isn't this a standard tube/shell barrel?
Thanks.

That's all I'm saying.. i guess we have to wait to see if it was flow or not.. but if you had hard water, no chemical or poor chemicals how long before you foul the coils..in your estimation?

[KnewYork]

Like I said, the OP didn't even know that it was a DX chiller. He should have been able to say to the maintenance people that there couldn't possibly be a restriction in the "chiller barrel tubing" because refrigerant is the only thing that flows through the tubes.

One of the things that causes the hard water chemicals to plate out is heat. That's why a condenser is far more likely to scale up. The heat of the discharge gas helps in the precipitation of the minerals in the water. I will tell you I am no water treatment specialist, but my SWAG (scientific wild ass guess) would be that it would take months. if not a year or more, for problems to show up on a closed loop chilled water system. Biologicals could present a whole different set of circumstances, but days or even weeks of running w/o chemicals would not, in my opinion, be sufficient enough to cause flow problems.

[dlove]

rats...evap evap....i was thinking condenser ...I stand corrected.

I still would get flow test done, but they may find a valve that broke and didn't open all the way...or some simple like that.. is hard for me to think the flow is due to being dirty.

[R123]

For what it's worth, I know of a place that had 6 30GA chillers built in 1974 with no water treatment all these years (chilled water), and 2 of them are still running.

[madhat]

I had a RTAA, that had plenty of flow, Trane Rep. replaced almost every sensor on it, and still had problems. I pulled the Glycol out of the barrel, figured out how much water it took. I ran a heated solution of Calgon HD thru it almost two years ago, to cut the Gel. Been working great since then. The Glycol is trashed, Dow confirmed this with their free testing. My work still hasn't replaced the Glycol

[Tommy knocker]

I agree on a closed loop would take awhile to foul evap enough to affect flow. In most cases. If however its not a closed loop, and only assumed to be, that changes the conversation drastically. I would suggest OP confirm it is closed loop, no mix tank, before fouling is dismissed. Even on DX barrels sludging can and will happen and can and will affect flow and approach and pressures and temps and so on.