AUTOFLAME Mk8 MM Installation And Commissioning Guide

3 Water Level Control
Page 48 Mk8 MM Expansion Features Installation and Set-Up Guide 04.09.2016
3.5.2 Operation
The water level detection probes use capacitance technology, whereas the 2
nd
low safety probe uses
conductive technology. Following basic electric circuit theory, when the probe is in the water in the
boiler and an electrical voltage is applied, the current will flow; when water level drops below the
probe, no current will flow. This is the basic principle of the 2
nd
low safety probe, if the water levels
drop below the cut-length of the probe, then a 2
nd
low water alarm will occur on the MM or for
standalone mode, the volt-free connection will open to indicate this alarm. When used with an MM, the
2
nd
low water alarm requires a manual reset.
3.5.3 Specifications
The specifications of the 2
nd
low probe include:
 Part number SLP70001
 Compatible with Mk7 MM and Mk8 MM
 Can be used with Autoflame system or as a standalone unit
 Probe can be cut to length to suit application
 Internal relay self-checking
 Conductive technology completely different to capacitance probes
 Stainless steel and PTFE construction
 Supplied with 2m (6ft) flying lead
 Quick connect multi-pin flying lead
 Volt free contacts for external safety devices or circuits
 Offsite status logging via Mk7 DTI and direct Modbus from Mk8 MM
 Tested and approved to UL standard
2
nd
Low Probe Flying Lead
The 2
nd
low probe is supplied with a 2m (6ft) flying lead, which has quick connect multi-pin end.
The cable shield is connected to the probe body.
Pin Description Wire MM Terminal
1 Optional ground connection (not used)
2 0V Power (DC or AC) Blue 4P-
3 12V Power (DC or AC) Red 4P+
4 RS485 Comms - Yellow 5T-
5 RS485 Comms + Green 5T+
6 Volt-free connection 1 (250mA max) Brown
7 Volt-free connection 2 (250mA max) Purple
If using the 2
nd
low probe for standalone operation, then the volt-free connections must be used; the
volt-free connection will be closed when water is detected and there is no system fault.

AUTOFLAME Mk8 MM Specifications

General

Brand	AUTOFLAME
Model	Mk8 MM
Category	Controller
Language	English