Technical Service Bulletin
Number
M920023
Date
12/2/2025
Model
Lineage 25 FW
Build Date
5/30/24-8/26/25
Technician
X
540000 620262
540130 910009
Part Number (s)

Air conditioner direct dump feature
Subject
Service Manager

X

Parts Manager

Warranty Admin

X

Sales Manager

X

Circulate To:
Air Conditioner may not cool unit efficiently.
Concern:

Remedy:

Install a direct dump feature to the a/c system, insulate front cabover area, install double bubble
insulation around a/c unit.

Flat Rate:

3.0 Hrs.

Grand Design Lineage M Series Insulation and Direct Dump Field FixesFix 1: Adding insulation to front bunk area
1. Remove interior grab handle by unscrewing at top and bottom
2. Remove loose items from bunk area to avoid damage
3. Remove caps and screw from front cap area plastic
4. Remove screen door. Screws are inset in screen door frame
5. Remove bunk curtain track by removing screws
6. Remove soft touch wingwall covers by opening caps and unscrewing
7. Remove bunk front plastic screws
8. Remove and disconnect ceiling lights that are installed on front plastic
9. Remove front molded plastic piece
10. Remove all front plastic pieces by cutting or disconnecting wires as needed.
11. Remove all front cab plastics
12. Using spray adhesive, add a layer of R7 insulation (Part #540000, can get locally) to entire
front area
13. Cover insulation with reflective foil (Part #540130) using spray adhesive, cut to fit.
14. Reflective foil over wing wall insulation.
15. Reinstall front plastics and pieces that were removed, hooking up any disconnected or cut
wires beforehand
Fix 2: Adding Double Bubble insulation to AC unit
1. Unscrew AC cover screws on roof. (Fig. 1A)
2. Remove AC cover
3. Take Styrofoam insert screws out. (Fig. 2A)

4. Remove Styrofoam cover
5. Drill (2) 1/8” weepholes as shown- (Fig. 3A). Caulk 3 open AC holes. 2 on passenger side,
one on driver’s side. (Fig. 3B)
6. Reinstall Styrofoam cover
7. Cut double bubble insulation (Part #620262), use adhesive spray and tuck behind AC and
wrap around. (Fig. 4A)
8. Reinstall AC cover

Fig. 1A

Fig. 2A

Fig. 3A

Fig. 3B

Fig. 4A

Fix 3: Add AC Direct Dump Vents (Part #710637)- (See attached repair diagrams).
1. Place jig over return air cover and mark both rout openings on soft touch. Use razor knife to
carefully cut soft touch around mark made from jig.
2. Use oscillating saw to cut out holes for vents.
3. Final rout out hole size is 7 5/8” x 3 ½”
4. Do not cut through edge of duct
5. Drill 6 1/8” pilot holes in direct dump vent as shown
6. Test fit vent in hole and test operation that it stays open when opened and closes when the
lock is pushed to the side. Modify holes if needed.
7. Foil tape opening to ensure no air escapes between ceiling and AC duct
8. Finished direct dump install, verify operation
Parts Ordering:
Please order as follows:
1- Part # 910009- Jig (Template)
2- Part # 710637- Vents
.064- Part # 620262- Double bubble insulations (Put in notes; 8 ft.)
128 sq. ft.- Part # 540130- Reflective foil