Laars MASCOT LX, Service Manual

Page: 41 / 94

35
Mascot LX Service Manual
Troubleshooting the 24V DC Power Supply
B2
Many of the controls in the boiler operate on 24V, including:
• The SIT controller and display panel
• Most of the sensors and switches that provide inputs for the controller.
Figure B1-1 in the last section shows the power distribution system. A transformer
develops 24V AC, which is later rectified to produce 24V DC.
There are two safety devices we should point out:
• A 2A circuit breaker for the 24V DC supply. This is mounted behind the lower
front cover. See Fig. B2-1
• F3, an 800 mA fuse, located on the back of the control board. The instructions
in Section B1 explain how to reach this fuse.
Some of the parts inside the power box can carry full line voltage. This voltage can
cause death or serious personal injury. Do not open this box or work inside unless
you have been trained in safe electrical service techniques.
Fig. B2-1 - Circuit breaker for 24V DC
(Shown with lower front cover removed)
2A circuit breaker for
24V DC power supply