Return Butterfly Valve; Other Connections; Boiler Or System Pump Control; Frost Protection - DeDietrich 310 ECO Series Installation And Operating Manual

8.8.5 Return butterfly valve 3-way valve (supplied by others)
A butterfly valve should be installed in return for each boiler module is hydraulically disconnected from the
system. 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 terminals X21-11 (neutral), X27-12 (power close)
and X27-13 (power open) on the 120-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 purge time of the
pump (set point code , 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 sections 8.9.1 & 13.1.2

Please refer to the document supplied with the return of 3-way valve for detailed installation
information.

8.9 Other connections

8.9.1 Boiler or System pump control

The Gas 310/610 ECO a power supply (120V max 2amps) to run or control an external boiler or system
pump. The boiler control will run the pump once every 24hrs 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!! Phase/Neutral sensitive!
Important!! For multiple boiler installations the system pump cannot use this power supply.
If the boiler shuts down the system pump will also shutdown.

8.9.2 Frost protection

The boiler must be installed in a frost-free area to prevent 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 44°F [7°C], the external heating pump connected to the boiler is switched on at
minimum capacity:
▪
Is below 39°F [3°C] the boiler is switched on at minimum capacity;
▪
Exceeds 50°F [10°C], the boiler and heating pump are switched off again. The pump now
has a fixed post-circulation time of 15 minutes.
Important!!
This frost protection only protects 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.
De Dietrich Gas 310/610 ECO
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