Merlin PM2+
User Guide
Rev: 2 05-19
4
2
Circuit Board Terminals
2.1
POWER
A 12v DC electrical supply should be supplied using the [+ - 12/24 VDC
Power].
2.2
FAN 1 & FAN 2 LIVE – Current monitoring
Located at the bottom of the main circuit board there are two
terminals for fan current monitoring, and these are marked up as [FAN
1 LIVE IN / OUT] & [FAN 2 LIVE IN / OUT].
The live feed from the fan speed controller should be taken through
these contacts. Each will monitor its own independent fan.
From a fan controller the live feed should be taken to the [IN] terminal
and the [OUT] terminal should wire to the fan motor.
Merlin panels 1500S / 2000S are sent from the factory with links in the terminals marked [SUPPLY
FAN PD SWITCHES & EXTRACT FAN PD SWITCHES] & [FAN1 PD SW & FAN2 PD SW]. If only one fan
is being monitored the relevant link should be taken out of the terminal connection.
These terminals are low volt only.
If both fans are being monitored – both links should be removed
and a connection should be supplied to the terminals marked on
the Merlin PM2+ panel [FAN PDS OUT].
There is an option to set a minimum and maximum running current for the fans to operate on.
If
the current goes above the or below these parameters the PM2+ will switch relay for NC
(normally closed) to NO (normally open) for relevant [FAN# PDS OUT] and on the main Merlin
panel the relevant supply/ extract fans LED will begin to flash for ~10 seconds before the Fan
Fault alarm will be illuminated and the gas solenoid valve connected will be isolated.
For more information see section 3 –‘How to set up the current monitors’.
