28
MB Pool & spa heater
All Models
DESOOTING PROCEDURE
CAUTION: SOOT IS COMBUSTIBLE. EXERCISE
EXTREME CARE. NEVER USE A WIRE BRUSH.
Soot can clog areas between fi ns and cause even-
tual tube failure. Any sign of soot at the base of the
burners or around the outer jacket indicates a need
for cleaning.
1. Disconnect top portion of unit. (See heat
exchanger removal procedure steps 1
through
6).
2. Remove burner tray (See burner drawer
removal
procedure.)
3. Take a garden hose and wash heat
exchanger,making sure soot is removed
completely
from
between
fi ns. Avoid
excessive water against refractory.
NOTE: DO NOT WIRE BRUSH.
055, 155, 185, 265 & 405 Models
UNITHERM GOVERNOR (U.G.) REPLACEMENT
1. Shut water, gas and electricity off, close
valves and relieve pressure.
2. Drain heat exchanger.
3. Remove retainer located under outlet
pipe
connection.
4. Remove spring and replace old U.G. with a
new
U.G.
5. Reverse above procedure to reinstall.
Extension Pieces (2)
Auger with Carbide Tip Wire Brush
To test the operation of the Unitherm Governor, place
in hot water (over 43°C) and watch for movement
against spring. If there is no movement, replace unit.
055, 105 & 155 Models
COMBUSTION CHAMBER REMOVAL
1. Remove heat exchanger (See heat
exchanger
removal
procedure).
2. Lift up and remove front and rear refractory
shield.
3. Remove refractory panels.
4. Reverse above procedure to re-install.
185, 265 & 405 Models
COMBUSTION CHAMBER REMOVAL
To remove combustion chamber, you must fi rst have
removed the heat exchanger. Unbolt metal combus-
tion chamber retainer from top and remove combus-
tion chamber panels individually.
Refractory Panels Top View
Refractory Panels Top View
ugrep.tif
Ensure no gaps
in corners
Ensure no gaps in corners
Gasket
Retainer Plug
Spring
UniTherm Governor
Gasket
Retainer Plug