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

LAARS HEATING SYSTEMS Page 10
5. Remove the flue collector assembly by lifting it
out of the chassis.
6. Remove the screws that fastens the gap closures
and put them aside.
RETAINING CLIP
Figure 19. Capillary Tube Retaining Clip.
Figure 18. Sensing Bulb Locations.
Figure 20. Hole Location, Left Side.
Attach Capillary
Covers on
Left Side
0.9 in. dia.
(23mm)
(Two holes)
LEFT
FRONT
1.9 in.
(48mm)
2.4 in.
(61mm)
2.4 in.
(61mm)
3.1 in.
(79mm)
7. Remove the three grommets.
8. Remove the drain valve and plugs. There are two
hex plugs, one on the left side, and one on the
right side, near the rear of the jacket. The drain
valve or plug is located on the left side near the
front (see Figure 16).
9. Remove the four screws that fasten the metal
channel covering the capillary tube on the right
side of the jacket. Lay the channels aside.
10. 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 18). 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 thermowell (see
Figure 19).
c. Pull the sensing bulbs out of the control
compartment.
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.
11. Use a pair of diagonal cutters to cut the wire
bundle tie in the control compartment.
12. On the terminal strip, disconnect the two brown
wires from No. 5 and No. 6 terminals.
13. Remove the flow switch conduit retaining clip
and the elbow leading into the jacket.
14. Reach inside the control compartment and
release the retaining nut in the upper right corner.
The nut should only be finger-tight.
15. 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.
16. Use a chassis punch to put two 7 /
8
inch (22mm)
holes in the front left side of the jacket (see
Figure 20).
17. Remove the front and rear tile covers (see Figure
16).
18. Lift out the heat exchanger assembly, turn it 180
degrees, and reseat the unit in the boiler with the
water connections on the left side.
19. Reinstall the front and rear tile covers.
20. Push the capillary tube(s) out through the lower
hole in the left side of the jacket.