Initial Lighting; Operating Sequence - Keston Heat 45 Installation And Servicing Instructions

50 initiAl liGHtinG

1. Check that the system has been filled and the boiler is not air locked -
air in the boiler could damage the heat exchanger. For this reason the
airvent located in the left top side must never be shut off.
2. Check that all the drain cocks are closed and any valves in the flow
and return are open.
3. Check that the GAS SERVICE COCK IS ON.
4. Fill the condensate trap with water before putting the unit into operation
(see Frame 60 for condensate trap removal).
5. Check the indication on the pressure gauge. If the pressure is less
than 1 bar the installation should be filled up first (sealed system only).
Keston Heat ~ flue Co
Max Rate ± 0.5%
Min Rate ± 0.5%

oPeRAtinG SeqUenCe

Demand On
& Temp. <Set point & Anti-cycle
done?
Fan off. Pump off
Standby
Keston Heat -
Installation & Servicing
INSTALLATION
% measurements (hot condition)
2
Keston Heat 45
9.3%
8.4%
yes
Burner Output controlled relative to
Heat Demand by varying Fan Speed
no
yes
6. Switch the electricity supply ON and check that all
the external controls are calling for heat. Check
boiler is set for winter operation - see Keston Heat
user interface basic operating instructions.
7. The boiler will commence the ignition sequence. If
after 5 attempts the boiler has failed to light then it
will lock out. Press the reset button to restart the
ignition sequence.
8. Operate the boiler for 10 minutes and check the gas
rate (Table 1). You should be able to read at least
90% of the nominal.
Keston Heat 55
9.5
8.4
Standby
Heat demand on?
yes
Pump On
Temp. < setpoint?
yes
Fan On
20s Fan Pre-purge
Spark Generator On
Gas Valve On
3s Ignition Period
Flame detected?
yes
Spark Generator Off
1st Stabilisation Period
burner on
Demand
off or Temp. >setpoint?
yes
Gas Valve Off
Pump Overrun
Heat Demand Off?
no
no
no
no
Note. The fan runs for
4 mins after the burner
switches off
no
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