MCA
Pro
45/65/90/115
MCA-Pro ISM Rv.4.1 2/2017
62
Control of external heating system pump
(Pump)
An external heating system pump can be connected to
the Pump terminals of the connector. The maximum
input power is 300 VA/ 0.4 FHP. Use an auxiliary relay
for a pump with a larger input.
Control of external three-way valve (3wV)
The external three-way valve (120 VAC) can be used
when connecting an indirectly heated DHW tank. The
neutral position of the three-way valve can be set using
parameter
p34
.
The three-way valve is connected as follows:
• N = neutral
• C = heating system
• D = tank
Control of external DHW hot water pump
(3wV)
It is also possible to connect an external DHW pump to
the terminals
3wV
. Connect the pump as follows:
• N = N pump
• D = L pump
• Q = Ground
CAUTION
If the neutral position of the three-way valve is
adjusted with parameter
p34
, the pump should be
connected as follows:
• N = N pump
• C = L pump
•
= Ground
Control of external gas valve (EgV)
If there is a heat demand, an alternating voltage of 120
VAC, 1 A (maximum) becomes available on the EgV
terminals of the connector to control an external gas
valve.
Operation signal and failure signal (Status)
The alarm or operation signal is selected using
parameter
p40
.
• If the boiler is operating, the operation signal can
be switched via a potential-free contact (maximum
120 VAC, 1 A) on the
NO
and
C
terminals of the
connector.
• If the boiler locks out, the alarm can be transmitted
via a potential free contact (maximum 120 VAC, 1
A) on the
No
and
C
terminals of the connector.
Pressure switch minimum Gps
The minimum gas pressure switch shuts the boiler
down if the inlet gas pressure becomes too low.
Connect the minimum gas pressure switch to the Gps
terminals of the connector. The presence of the gas
pressure switch must be set using parameter
p41
.
n Heat Recovery Unit (Hru)
This connection will not be used in Canada or USA.
4. Installation
Summary of Contents for MCA Pro 115
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