AUTOFLAME Mk8 MM User Manual

3 Commissioning Procedure
Mk8 MM Manual Page | 69
3.3 Servomotors
Autoflame supply three standard sizes of servomotors – small, large and industrial, which can be used for all
channels. Autoflame fuel valves require small or large servomotors only. Both small and large servomotors
can be configured to drive clockwise or counter clockwise to open a valve or damper. Servomotors can be
installed in any orientation; 2 fixed rotation positions if using Autoflame valves. For layout of the small, large
and industrial servomotors please refer to the Valves and Servomotors manual.
Viewing the shaft end-on, from the potentiometer end, all servomotors drive in a clockwise direction if power
is applied between the LIVE and CW terminals, and counter clockwise if the power is applied between the
LIVE and CCW terminal.
The operation of fuel valves and air dampers is often such that they open in a clockwise direction. If the
operation needs to be reversed, it is necessary to swap various wiring connections between the MM and the
servomotor(s). An example of reversing the operation of a servomotor is shown in Figure 3.3.3.
Note: Servomotors are supplied by the factory set at 0.0
o
position. Remember that this position may
not necessarily automatically position the damper at 0.0
o
or a closed position. This must be
physically checked. Failure to do so can result in serious injury or death.
3.3.1 Adjusting the Servomotor Potentiometer
Before a burner is fired it is essential to set up each Micro-Modulation servomotor. A tamper proof
screwdriver is required (please contact Autoflame).
Usually control valves/air dampers that the servomotors drive, move through up to 90.0
o
angular degrees.
The MM system has the ability to drive valves through 360.0
o
degrees, but the MM will only display from -
6.0
o
to 96.0
o
degrees.
All Channel 1 to 4 and 7 readings displayed on the MM are in angular degrees. It is necessary to adjust the
potentiometer in the servomotor assembly so that the MM reads 0.0
o
when the relevant valve/damper is at its
fully closed position. The technician must physically check the mechanical position of the dampers and
valves, whilst all servomotors are set to 0.0
o
before leaving the factory this may have changed during
shipping. DO NOT ASSUME THEY HAVE BEEN PREVIOUSLY SET CORRECTLY.
Put the MM into the commissioning mode and press CLOSE to position the valve/damper mechanically by
using the appropriate up and down buttons (see section 3.4.2).
Remove the servomotor cover.
For air servomotors carry out the following procedure:
Use the channel 2 up/down buttons on the MM to position the air damper to its physically closed position.
Loosen the two tamper proof screws just enough to enable the potentiometer to rotate. Rotate the
potentiometer clockwise or counter clockwise until the relevant channel reads 0.0. Tighten the two tamper
proof screws gently until the potentiometer is secure. Do not over tighten the screws. Check that the display
still reads 0.0. If incorrect repeat the adjustment process.
For fuel servomotors carry out the following procedure:
On Autoflame gas, oil and gas/oil piggy-back valves it is necessary to remove the servomotor. Manually
position the oil/gas valve slot to its closed position. Observe the position of the drive pin on the servomotor.
Use the relevant channel up/down buttons to position the pin so that when the servomotor is reassembled to
the valve it is in line with the slot. Reassemble the servomotor to the valve, loosen the two tamper proof
screws and proceed to adjust the potentiometer position until 0.0
o
is displayed. Use the external position
indicator to ensure the valve is in the fully closed position.

AUTOFLAME Mk8 MM Specifications

General

Brand	AUTOFLAME
Model	Mk8 MM
Category	Controller
Language	English