8
L-3571 ENGLISH
E
VAPORATOR
•
Flat Plates -
Stainless-steel evaporator plates are an excellent choice for use in a bait-freezing, fish-keeping
application. Plates with backs may be mounted directly to the wall, or mounted with stand-offs so that there is an air
space behind the plate. Care must be taken to route the connecting tubes carefully to an accessible location outside
the box. When installing, consider the necessity of cleaning the box. Seal the tubing exit holes to prevent ambient air
intrusion. See
Figure 2: Various Flat-Plate Evaporators, page 16
.
•
Wrapped Box -
This type of box has a clean interior because the evaporator is wrapped around the outside of the box
walls. The box must be installed in such a way that it can be serviced or replaced without causing damage to it or to its
associated refrigeration lines or other components. Dometic cannot be held liable for any damages caused by moving
the box. Service should be done by trained professional technicians only. Refer to the Owner’s Limited Warranty Policy
document for a full explanation of what is and what is not covered under warranty.
Do not drill a hole in this box unless certain of the location of the tubing and that the tubing can be avoided. It is easy to
drill a hole in the tubing resulting in loss of refrigerant and the voiding of the warranty. In order to detect location of
refrigerant tubing, turn system on and watch for frost lines. Frost lines will appear where there is tubing.
•
Insulation -
Insulate all boxes with a minimum of 2" (5 cm) of R7 insulation. Use 4" (10 cm) of R7 on vessels where
power is not constantly available. Insulation thickness is important to the performance of the system, and more
insulation offers better performance.
TXV P
LACEMENT
Typically, the Thermostatic Expansion Valve (TXV) bulb assembly is pre-made by Dometic, as shown in “Single-Plate System”
on page 17. The TXV must be installed in an accessible location and fastened properly. Recommended location of the TXV is
as close to the wrapped box or the plate as possible. The TXV sensing bulb is to be properly located and secured on the outlet
(suction line) of the last plate in series as close to the plate as possible. Recommended location is on a horizontal portion of
tubing on (between 3:00 and 9:00 o’clock position). The full length of the bulb should be in good thermal contact with the
refrigerant tubing. Attach it to the closest straight piece of tubing exiting the last box. If either the expansion valve or its sensing
bulb is located outside of the box, each part must be properly insulated to protect against condensation, as well as to allow
accurate temperature sensing of the bulb. The bulb must be secured to the pipe with a metal clamp to ensure firm contact with
the pipe and prevent movement. Plastic ties are not acceptable. Refer to “Adjusting the TXV” on page 13.
On systems with two plates, the TXV is connected to the inlet side of the first plate, and a jumper line is attached between the
plates. The suction line then returns to the condensing unit.
Q
UICK
-C
ONNECT
F
ITTINGS
All plates and lines have quick-connect fittings. Quick-connect (QC) fittings allow for the connection and disconnection of
refrigerant lines with minimal loss of refrigerant. They also allow for the unit to come factory charged with refrigerant. All
connections are polarized so that mis-connecting the lines, condensing unit, or evaporator is avoided. If installed correctly, they
will not leak. The majority of problems with these have been leaks due to not tightening the connections properly. Over-
tightening can damage the fitting. QCs are a one-piece model and may be tightened securely at the union nut.
Procedure for connecting the QC fittings:
1.
Lightly lubricate the gasket seal and threads on the male threaded coupling with refrigeration-grade oil.
2.
Thread the union nut of the female coupling onto the male threaded coupling by rotating the union nut clockwise.
3.
Start the connection by hand, and then tighten the female thread connection with a 15/16" wrench while holding the
opposite coupling with a 7/8" wrench (must use two wrenches to avoid damage). This should be tightened to 10-12 ft-
lbs with a torque wrench.
4.
ALTERNATE PROCEDURE WITHOUT A TORQUE WRENCH: Tighten clockwise the female coupling nut until the
coupling halves “bottom out” or a definite resistance is felt. This will require about 6 full turns. Using a marker or ink
pen, mark a line lengthwise from the female coupling hex to the male hex. Then tighten an additional 1/4 to 3/8 turn.
The misalignment of the ink line will show the degree of tightening. This final turn is necessary to ensure that the knife-
edge metal seal bites into the brass seat of the coupling halves, forming the leak-proof joint.
NOTE
Some custom applications use flare fittings on line sets in conjunction with QC fittings.
