LAARS Mighty Therm VW-PW (Sizes 175-400) - Installation, Operation and Maintenance Instructions - Manual (Page 10)

LAARS Heating Systems
Page 10
9. Remove the four screws that fastens the metal
channels covering the capillary tube on the right
side of the jacket, and lay the channels aside.
10. In the control compartment, find the manual reset
high-limit switch box (see Figure 15) and loosen
the screw on the top to remove the cover.
11. Loosen the screw that fastens the white wire and
remove it from the terminal. Pull it out through
the top of the case and separate the other white
wire from the red wire coming from the fuse
holder. Gently pull the two white wires out of the
control compartment and coil them on top of the
heat exchanger.
12. A temperature control sensing bulb is located in
the front of the header on the inlet side and a
manual reset hi-limit sensing bulb is located on
the back side of the header on the outlet side (see
Figure 17). Remove these sensing bulbs from the
header. The following steps for removal apply to
all sensing bulbs:
a. If there is more than one capillary tube coming
out of the header, label the capillary tubes.
b. Loosen the screw on the capillary tube
retaining clip, then gently pry the clip apart
until it comes free from the temperature
control (see Figure 18).
c. Pull the sensing bulbs out of the temperature
control.
d. Gently pull the capillary tubes into the control
compartment.
e. Pull the temperature sensing bulb out of the
header, and temporarily route it to the front of
the heater.
13. Use a pair of diagonal cutters to cut the plastic
tie around the wire bundle in the control
compartment.
14. On the terminal strip, disconnect the two brown
wires from No. 5 and No. 6 terminals.
15. Remove the flow switch conduit retaining clip
and the elbow leading into the jacket.
16. Reach inside the control compartment and
release the retaining nut in the upper right corner.
The nut should only be finger-tight.
17. When the conduit is pulled away from the jacket,
pull the two brown wires out of the control
compartment. Coil the conduit and wires on top
of the heat exchanger.
18. Use a chassis punch to put two 7/8 inch (22 mm)
holes in the front left side of the jacket (see
Figure 19).
19. Remove the front and rear tile covers (see
Figure 15).
Figure 19. Hole location, left side.
Figure 17. Sensory bulb locations.
Figure 18. Retaining clip removal.
7. Remove the three grommets.
8. Remove the drain valves and plug. There is one
hex plug on the left side, near the rear of the
jacket. The drain valves are located on the left
side and right side of the heater (see Figure 9).