Original message
| miller2000
 |  "some help with a bang"
, posted Sat 23 Sep 18:00  
1. If you have a 1 horse power compressor and need to replace the cap tube but you don't know the size of the original tube, I have paper that states for a 1 to 1.2 horse power compressor you need #4 at 51 in length, it also said that you need to play with the length to application.
Q. If I increase the length will it increase the superheat or decrease it?
2. You have a 2 ton geo unit with a 2 ton txv and a 2ton air coil, you find the water coil was replaced and the one that was put in was smaller then 2 ton.
Q. What would you expect to see in the gages and superheat?
3. Q. Why are most water coils single pass not muilt tube?, which one will perform better and why?
4. Q. how do you size a piston (sliding) orifice?
5. Q. Can you use a cap tube on a heat pump, do you put it in the middle of the liquid line between the coils?
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Replies:
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| Freezone12
| "Re(1):some help with a bang" , posted Sat 23 Sep 21:53
quote:
1. If you have a 1 horse power compressor and need to replace the cap tube but you don't know the size of the original tube, I have paper that states for a 1 to 1.2 horse power compressor you need #4 at 51 in length, it also said that you need to play with the length to application.
Q. If I increase the length will it increase the superheat or decrease it?
A. increasing the length will add static pressure to the condensing system, thereby increasing pressure. this will allow for more subcooling and therefore additional refrigeration effect when charged accordingly. superheat should be adjusted per manufactuers specifications for the compressor. the superheat you ultimately wind up with will depend on the load from the evaporator. but adding a small amount of cap tube should decrease superheat, meaning lower saturated suction temperature. keep in mind the law of diminished returns when playing around in this arena. you must understand how many BTU's the system is capable of dealing with to insure proper application.
quote:
2. You have a 2 ton geo unit with a 2 ton txv and a 2ton air coil, you find the water coil was replaced and the one that was put in was smaller then 2 ton.
Q. What would you expect to see in the gages and superheat?
A. high head pressure-low suction-high superheat.
quote:
3. Q. Why are most water coils single pass not muilt tube?, which one will perform better and why?
A.
(a.) cheaper to manufactuer.
(b.) 6 of one, half dozen of the other. servicability and cost is generally the deciding factor.
quote:
4. Q. how do you size a piston (sliding) orifice?
A. from a manufactuers load table.
quote:
5. Q. Can you use a cap tube on a heat pump, do you put it in the middle of the liquid line between the coils?
A.
(a.) possibly, but have never seen it done.
heat pumps are most often found in applications where energy efficiency is the prime consideration. TXV's are known to be more energy efficient than cap-tubes.
(b.) not certain what you're asking, but if this were to happen, I would probably use a 'rose bud' type refrigeration distributor. different strokes for different folks.
refrigeration is an in-exact science. there is always more than one way to skin a cat.
_______________________________________
If it don't fit
force it.
If it breaks
it needed to be replaced anyways.
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