carrier 30hs 160

[Joshieboy]

hey everyone! I'm working on a older carrier chiller and im in the process of checking the individual tubes in the chiller barrel and was wondering if anyone knows how many tubes can be plugged before it affects the capacity. there are two seperate circuits each with 129 tubes that are 5/8in dia and 9' 2 1/2" long. its a 160 ton unit, any help will be appreciated

[serviceman]

is 10 % of the total tube that can cancel during your case would be 12 as maximum permitted by any manufacturer

[Argus]

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10% plugged tubes at random is considered acceptable.

You may want to reconsider this if the defective tubes are all grouped together as it may show an underlying problem and affect the evaporators performance.

Any more than that will need a re-tube, which can be done but is a first-class hassle in terms of work and cost - it may not be viable with a chiller that age.

You may want to look at your TEV after you plug any amount of tubes to make sure that the superheat is still within acceptable limits, especially at reduced loads.

One other thing with Carrier chillers of a certain vintage: the TEV entry point, if I recall, is at the base of the evaporator tube sheet and the suction exit is at the top. Carrier evaporators are configured with the water entry and exit points at the top of the bundle and a set of weirs inside that direct the water flow up and down, contra-flow over the tubes. Over time in non-sealed systems sediment may collect in the lowest points and block off some of the lowest tubes, affecting performance to the point where the evaporator becomes seriously undersized due to the reduced water contact. This is the part where the risk of tube-stress is greatest.

If you have that many tubes to plug and are at the stage of invasive surgery, so to speak, why not drift a few tubes out and have a look at the cause of any damage suspected?


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[Magoo]

As p earlier posts the max recommended by Carrier is 10%, are they leaking internally or at the tube sheets.
Carrier can supply Elliott two peice brass blanking plugs. If you are going to remove tubes, they have stay tubes that are crimped to position the internal plastic baffle plates in position. They are not removable and should be plugged if leaking internally, they are indicated in the service and installion manual supplied with chiller if you can find the manual.
If tubes are leaking at tube sheet first try hand re-rolling with tube expander.

[fintan]

As p earlier posts the max recommended by Carrier is 10%, are they leaking internally or at the tube sheets.
Carrier can supply Elliott two peice brass blanking plugs. If you are going to remove tubes, they have stay tubes that are crimped to position the internal plastic baffle plates in position. They are not removable and should be plugged if leaking internally, they are indicated in the service and installion manual supplied with chiller if you can find the manual.
If tubes are leaking at tube sheet first try hand re-rolling with tube expander.

Hi All,

Sorry for hijacking your post Joshieboy but it might be of assistance to you as well.
We have also found a leak in one of the evaporator tubes and have got the Elliott two brass piece of Carrier to plug the tube. Our problem is, the leak is in one of the swagged tubes but it is also next to the cross separator of the 1st and 2nd pass of the end plate so we can't use the Elliott piece at that end (the lip of the brass ring is in the way). Is there tapered plugs that can be used to seal the tubes available from a UK wholesaler, the ones here in Ireland don't know what I'm talking about.

Thanks in advance

[Magoo]

Trim the side off to clear partition divider, so long as you have at least half the shoulder there, it is there to stop the whole thing going up the tube. Don't forget the loctite on taper plug and barrell outer sealing to tube, clean tube surface and use the loctite cleanining spray as well.

[fintan]

Thanks for your reply Magoo