Anybody have bad experience with Multistack (Trane) Modular Chillers?

[rose4rand]

The multi stack is already in place and started up buy Trane about 6 weeks ago. Two ruptured heat exchangers already. Sand filter on system that fiters sub micron. Water looks clear, but when pulling down chiller to get to heat exchanger, red thick slim in the strainers. Just on a fact finding mission.

I have a customer with a Multistack, just about a year old. has had (3) HX failures already. i treat the water and I know it's clean. Failure has occurred on the inlet and outlet on chambers 73 and 74. They had pitting. In look at the flow pattern at this particular point, there is none. We suspect microbiological corrosion due to high chlorides excreated by bacteria. What exactly happened to your HX. Where did it fail? Are you treating the system?

[pipefitter fred]

I have a customer with a Multistack, just about a year old. has had (3) HX failures already. i treat the water and I know it's clean. Failure has occurred on the inlet and outlet on chambers 73 and 74. They had pitting. In look at the flow pattern at this particular point, there is none. We suspect microbiological corrosion due to high chlorides excreated by bacteria. What exactly happened to your HX. Where did it fail? Are you treating the system?

Don't have much info right now. Trane has sent HX to factory in Switzerland. Owner does not treat cooling towers, so engineer did not spec any chemical., just sand fiter. We disagreed with this from the begining.

[Randy S.]

Filters won't pull out dissolved solids.
The whole idea that you can filter enough to keep the HTX clean is an OEM lie.

[TDY_Tillman]

Pipefitter Fred,

Rose4Rand is on target here.
When certain microbes die and breakdown, one of the byproducts is acid. Chlorides and acid are not friendly to stainless steel or copper braze material and will cause HX failure in high enough concentrations.

[hvacdoctor]

Had various ruptures on the MS recip 50ton modules mostly evaporator ruptures. Labor and head aches are not worth the repair- replace the module. Never found out why except we think it may have been restricted possibly and froze up?

One major maintenance task MS recommends is a heat exchanger cleaning on both evap and condenser side. They sell a cleaning 151A Cleaning Kit and you use a very mild Phosphoric or Sulfamic (no hydrochloric acids) mix with water. NOTE this maintenance is very labor intensive you must dissembly all the grooved piping strainers etc.

If you have a lot of solids and problems with strainers plugging try the DDRS-210 flush systems, it back flushes the strainers. I also recommend a spare set of strainers to rotate if possible.

Bottom line is they are very maintenance intensive: your customer must know this before they invest in one of these.

[duke of earl]

I worked on a multistack last year that had the Trane scroll compressors and what a piece of crap! The frame was flimsy and if you sneeze at it, it just might fall over!

[drivewizard]

Had various ruptures on the MS recip 50ton modules mostly evaporator ruptures. Labor and head aches are not worth the repair- replace the module. Never found out why except we think it may have been restricted possibly and froze up?

One major maintenance task MS recommends is a heat exchanger cleaning on both evap and condenser side. They sell a cleaning 151A Cleaning Kit and you use a very mild Phosphoric or Sulfamic (no hydrochloric acids) mix with water. NOTE this maintenance is very labor intensive you must dissembly all the grooved piping strainers etc.

If you have a lot of solids and problems with strainers plugging try the DDRS-210 flush systems, it back flushes the strainers. I also recommend a spare set of strainers to rotate if possible.

Bottom line is they are very maintenance intensive: your customer must know this before they invest in one of these.

That is Funny! I needed a good laugh. You think the Salesman are going to ruin a high commission sale by telling the Customer beforehand that they will spend a small fortune on maint. every year?

[jchaters]

Aermec NRL 15 - 270 Tons Europe's best now available in the US Heat Pumps and Chillers. 410a 100 percent heat recovery, free cooling etc. Ver good efficiencies.

[hvacdoctor]

FYI Installed replacement R407C modules last few years, ruptured heat exchanger on each module. Can not tell yet if it was evaporator or condenser. We do have an open tower on it, with separator system.

I can not believe a unit less than year old can fail like this!

[hvacdoctor]

Update on 507c MS50 module replacements. Installed new module in 2011 ruputured one heat exchanger already and new module less than year old has also ruptured an heat exchanger. Not sure what side at this point but this should not happen on new machines. Customer is furious right now! MS says we will give you new parts? Really!!!!!!!!!! water logged POE oil system and they want to give us new parts? UNREAL. How about new chillers. Best is they want us to remove defective hx to send back to check it? ok so I take down the other working side in mid summer. NOT.

FYI Installed replacement R407C modules last few years, ruptured heat exchanger on each module. Can not tell yet if it was evaporator or condenser. We do have an open tower on it, with separator system.

I can not believe a unit less than year old can fail like this!

[19characterusername]

Multistack like any other brazed plate condenser system cannot be used on open condenser systems due to fouling. Full stop. A proper multistack design must incorporate a plate and frame in the condenser water system a closed circuit tower or a remote evaporative condenser. Arctichill sell a modular with a cleanable condenser.

We do a lot of modulars in NYC due to FDNY rules limiting hp of unsupervised compressors on each circuit (find me the owner who cares about cop of 3 vs 6 on a 300 tr load when you have to pay the extra salary and benefits to each of the chiller operators you'll need to hire to get 6 cop.) You will want flow control valves on each module. It's mandatory for variable primary loops and will help with chiller efficiency under low load. Conversely you must have a variable primary loop if you go with control valves on your modules.

[maxster]

ever see the mouse trap POS the factory invented to clean the plate heat exchangers in place.if you don't have a plate heat EX closed loop tower they will not last on the water side from day one.

[jpsmith1cm]

Guy,

I'm not going to read the whole thread.

Should I move it to another, more appropriate forum?

Chiller forum, maybe?