Protherm 100 User Instructions - page 21
21
operation - connections to overheat thermostat are mains voltage.
•
Locate overheat thermostat (
a
) to left hand side of sealed chamber above
thermistor, see diagram 23.
To gain access to the thermostat, proceed as follows:
•
Unscrew and remove two screws securing the lower grille on the left bot-
tom of the boiler.
•
Unscrew and remove two screws securing the left side cover.
•
Remove the left side cover by pulling forward and aside.
•
Unclip overheat thermostat from pipe.
•
Pull off electrical connections from thermostat.
•
Fit replacement overheat thermostat in reverse order to removal.
Note:
No heat sink compound is required. The polarity of the connections is
not important.
To replace thermistor
•
Locate thermistor (
b
) clipped onto flow pipe to left hand side of sealed
chamber below overheat thermostat, see diagram 23.
•
Unclip thermistor from pipe.
•
Pull off electrical connections from thermistor.
•
Fit replacement thermistor in reverse order to removal.
Note:
No heat sink compound is required. The polarity of the connections is
not important.
To replace printed circuit board (PCB)
•
From behind lower control panel, unscrew and remove six screws securing
PCB cover to panel.
•
Pull off five molex type electrical plugs from PCB.
•
Remove screws securing PCB to panel and lift out PCB.
•
Fit replacement PCB in reverse order to removal, ensuring that domestic
hot water and central heating temperature control spindles engage properly
into PCB.
•
Potentiometers on PCB and user controls need to be set to max. before fit-
ting.
To replace timeclock
•
Remove PCB cover as described in
‘To replace PCB’
•
Disconnect clock electrical connections from PCB. Unclench and remove
plastic clips securing timeclock to lower front panel.
•
Remove timeclock from panel.
•
Fit replacement timeclock in reverse order to removal.
To replace heat exchanger
•
Drain down heating circuit of boiler only as described previously.
•
Remove sealed and combustion chamber covers as described
previously.
•
Unscrew screws securing lower grille.
•
Unscrew and remove screws securing left and right side covers.
•
Remove both side covers by pulling forward and aside.
•
Pull off spring clips securing heat exchanger pipes to heat ex-
changer.
•
Manoeuvre heat exchanger pipes down to disengage from heat
exchanger.
•
Remove heat exchanger by sliding forward and out of boiler.
•
Fit replacement heat exchanger in reverse order to removal.
•
Open isolating valves on flow and return connections, refill, vent and pres-
surise boiler. Check for leaks.
Diagram 23
Diagram 24
Diagram 25