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Originally Posted by jayguy

i have worked on starters that have been cursed before.

Sorry, should be "course" ( A learning program, as in a school.), or maybe better word like "training".

I see 8 stages here ,not four ....

Originally Posted by zlotvor

...but the starter curse helps you much...

i have worked on starters that have been cursed before.

Originally Posted by jborges

Hi my name is Javier Borges I am from PR right now I am installing 20 Tons Chilled water system using 4 Trane 4TTZ060 condensing units and 2 10 tons plate HX. Right now I have trouble deciding which DDC Controls to use should I use Trane Controls (++++++++++ Expensive) or my trusted control supplier which supplies Trend Controls. For those of you that do not know these trane units have two compressors inside of them and requiere a special wiring harness to connect them to any control either Trane or Trend. Please reccommend thanks.

Hi,
I'm not familiar with those two, but did you checked the Siemens Climatix series OEM controllers? They offer two basic variants, one for chiller control an done for heating substations. The controllers are freely programmable, can communicate over a range of buses (KNX, LON, Modbus, Mbus, BACnet) and they are cheap. The learning curve is pretty steep, but the starter curse helps you much, I can help you here also.

Originally Posted by jborges

Will present Pros/cons to the owner and let them decide! Still waiting for the answer to my first question that was if it was you which controls company would you use? I am still waiting for some parts to arrive like pumps some control valves, chilled water insulation will be done too, etc

Air handling side work is already done except grills and diffusers.

Cannot answer that question correctly as I do not know anything about Trends products but you are the one with the final answer and sounds like some knowledge of Trends product

Will present Pros/cons to the owner and let them decide! Still waiting for the answer to my first question that was if it was you which controls company would you use? I am still waiting for some parts to arrive like pumps some control valves, chilled water insulation will be done too, etc

Air handling side work is already done except grills and diffusers.

Did you decide who's DDC controls you will use????

Originally Posted by Letonil

What bypass valve?

Please read the whole post and you will find mention of a bypass valve.


You will find out that if you come to this forum and only read the first post and then comment without reading all that your opinion will eventually become null and void because people will learn that you are not paying 100 percent attention to what you are reading.

Originally Posted by Letonil

What bypass valve?

Due to the system been built with two way control valves the system needs a bypass with a proportional control valve to relieve system pressure when valves start to close.

Looks like fun, sounds like you've got it covered. Ive done a few retrofits but never just built my own chiller.
Let us know how it turns out.

what bypass?

Originally Posted by berg2666

And your thoughts on the bypass valve???

What bypass valve?

I am using a DDC based control system because it gives me the best control of the system, and the fancoil units in the house. I already have done all things for protecting the system including: freezestat, dp switch (is more accurate than a flow switch), on/off control valves for HX when full load is not neccesarry, planning on putting high and low ref pressure sensors to communicate to the controler. These CU start using the big compressor and when the load is acheived the small compressor starts that is the way the units saves energy. The thing with the CU is that if you do it wrong the compressors start failing and after a couple of failures Tranes does not warranty them at least locally this is my main problem. Have known of this problem from an early experience from another contractor but the system was with a multiple cu units split system.

Originally Posted by Letonil

Anyway, you can use an aditional 4 stage simple thermostat. Don't worry about the head pressure control
of the comps. it's probably in the condense units.
I forgot to mention that you must install a seperate water pump with a check valve on the discharge side
for each heat exchanger and please don't forget the safety devices such as water flow switch and freeze protector
for each heat exchanger. Cheers

And your thoughts on the bypass valve???

Sorry, I didn't notice

Originally Posted by berg2666

There is more then four stages here, each condensor has two stages.

Anyway, you can use an aditional 4 stage simple thermostat. Don't worry about the head pressure control
of the comps. it's probably in the condense units.
I forgot to mention that you must install a seperate water pump with a check valve on the discharge side
for each heat exchanger and please don't forget the safety devices such as water flow switch and freeze protector
for each heat exchanger. Cheers

Originally Posted by Letonil

The fan contact will run the water pump. Hopefully the condensing units are equipped with essential safety
devices and solenoid valves( not essential in this kind of a system). Make sure the the pump
is off delayed. Cheers

There is more then four stages here, each condensor has two stages.

4 stage control + fan

The fan contact will run the water pump. Hopefully the condensing units are equipped with essential safety
devices and solenoid valves( not essential in this kind of a system). Make sure the the pump
is off delayed. Cheers

So you are looking at 9 binary outputs, 2 binary inputs, 5 analog inputs, 1 analog output. Are you isolating the heat exchangers from each for low load conditions? Did you provide head pressure controls on the condensing units? How about a flow meter instead of DP?

Interlock your pump with the flow switch and set up a freeze protection. I don't guess it wouldn't much matter what controls you use. As far as staging goes, looks like x controls will just bring on more compressors in order to compensate for the load. Good stuff.

I don't know your condensing unit's exactly but it my understanding that only one compressor runs at a time correct and not a true two stage?

Originally Posted by jborges

The units are the one that have the double compressor and they are going to be used on high end residence for chilled water. I have already consider a freezestat, and every other sensor in that need to be done. The pumps will be controlled with the same DDC controls that will be installed with DPS and Transmitter for bypass valve. This is my third system that I have built but never with these condensing units. The hx suction and liquid connections are crossed blow them with nitrogen before doing installation.


Those isolators are electrical PVC Pipe cut at 3"

The units are the one that have the double compressor and they are going to be used on high end residence for chilled water. I have already consider a freezestat, and every other sensor in that need to be done. The pumps will be controlled with the same DDC controls that will be installed with DPS and Transmitter for bypass valve. This is my third system that I have built but never with these condensing units. The hx suction and liquid connections are crossed blow them with nitrogen before doing installation.


Those isolators are electrical PVC Pipe cut at 3"