Options/ Accessories; 14 8.8.1 System Pressure Sensor; 14 8.8.2 Gas Valve Leak Proving System Vps; Minimum Gas Pressure Switch - REMEHA Gas 310 ECO Technical Information

8.8 Options/ accessories

8.8.1 System pressure sensor
The system pressure sensor shuts down the boiler
(with shut-off code b ^@) when the minimum water
pressure is reached (adjustable 0.8 to 6.0 bar - factory
setting 1.0 bar, see section 13.2.12). The hydraulic pres-
sure sensor must be connected to the 5-pin female plug
X22 on the 24-volt terminal strip.
Press the s and e keys simultaneously for two sec-
onds to indicate the presence of the hydraulic pressure
sensor in the control unit.
Important!!!
g
The system pressure sensor is
suitable for pressures up to 4 bar)
Important!!!
g
This function is only operational
when a system pressure sensor is connected and acti-
vated (parameter J).
8.8.2 Gas valve leak proving system VPS
The gas valve leak proving system checks and operates
the safety valves on the gas valve multiblock. The test
takes place before the boiler pre-ventilation phase. In
the event of a leak between the two safety valves in the
gas valve multiblock, the boiler will lock out and show
failure code 89 or 90 on the display.The gas valve
leak proving system must be fitted to the boiler and
connected to the 3-pin female plug X21 on the 24 volt
terminal strip and the control set to recognise it using
parameter J in setting mode (see section 13.2.13).
Important!!!
g
This function is only operational
when a gas valve leak proving system is connected and
activated (parameter J).
8.8.3 Minimum gas pressure switch (suitable for
gas pressures up to 30 mbar)
The minimum gas pressure switch (set to 17 mbar)
shuts down the boiler (shut-off code b @^) if the
inlet gas pressure becomes too low. The minimum gas
pressure switch must be connected to the 3-pin female
plug X21 on the 24-volt terminal strip. The connection is
automatically detected by the boiler control.

8.8.4 Flue gas damper

In a cascade configuration, the flue gas damper pre-
vents flue gases from being discharged through a non-
operating boiler. Therefore, the boiler can be installed
on an over pressure flue system (Over pressure flue
systems enable much smaller diameter flue ducts to be
used).
The flue gas damper must be connected to the 4-pin
female plug X14 on the 230-volt terminal strip.

8.8.5 Return butterfly valve (not Broag supply)

A butterfly valve can be installed in the return for each
boiler module to ensure that a non-operating boiler mod-
ule is hydraulically disconnected from the system. When
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Gas 310 ECO
the return butterfly valve is fully open, the valve end
switch contact is closed, allowing the boiler to run.
The return butterfly valve must be connected to termi-
nals X27-11 (neutral), X27-12 (power close) and X27-13
(power open) on the 230-volt terminal strip.
The end switch on the return butterfly valve must be
connected to the external interlock terminals X29-3 and
X29-4 (first remove bridge). After boiler shut-off, the
power supply will remain on X27-13 keeping the valve
open during the post-circulation time of the pump (set
point code 2), then switch to X27-12 to close the valve
(this remains valid even if no pump has been connected
to the control box).
Also see section 8.9.1 and section 13.1.2

8.9 Other connections

8.9.1 Boiler or System pump control

The Remeha Gas 310 ECO has a facility to provide a
power supply (230V Max 2 amps) to run or control an
external boiler or system pump.
The boiler control will run the pump once every 24 hours
when the boiler not enabled to prevent sticking and
will also provide a run on period at the end of a heat
demand (parameter @, see section 13.1.2).
Important!!
g
phase/ neutral sensitive!
Important!!
g
For multiple boiler installations
the system pump cannot use this power supply. If the
boiler shuts down the system pump will also shut down.
Contact load terminals X27-9 (neutral) and X27-10 (live):
Voltage : 230 volts
Maximum current : 2 A.
The hydraulic resistance of the boiler at a dT of 11°
and 20° for the various output variants of the Remeha
Gas 310 ECO can be found in table 02, section 4.2

8.9.2 Frost protection

The boiler must be installed in a frost-free area to pre-
vent freezing of the condensate drain.
If the temperature of the heating water drops too low the
integrated boiler protection activates under the following
conditions.
If the boiler flow temperature:
- is below 7°, the external heating pump connected to
the boiler is switched on by the control unit;
- is below 3°, the boiler is switched on at minimum
capacity;
- exceeds 10°, the boiler and heating pump are
switched off again. The pump now has a fixed post-
circulation time of 15 minutes.
Important!!
g
This frost protection only pro-
tects the boiler. Other measures must be employed to
protect the building and system and will depend which
parameters are set or what form of external controls are
in use.
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