Cleaning The Heat Exchanger; Cleaning The Siphon - Benchmark 27i System Compact Installation, Commissioning And Servicing Instructions

▶ Check the CO/CO readings against the information in table 28 & 29.
2
▶ Check that the CO is less than 200ppm.
▶ Return the boiler to maximum, by pressing the UP arrow button, and
re-check the CO/CO .
2
– "Max" will flash at the bottom left of the screen.
– The boiler will take approximately 30 to 35 seconds to ramp up to
maximum output.
– Allow the boiler to stabilise at maximum output for at least 10
minutes.
▶ If correct, press the button and the boiler will return to normal
operation.
▶ Re-assemble and refit boiler case.
NOTICE: Minimum CO2
▶ The minimum CO
2
that the maximum CO
NG Appliances
Output CO Reading
2
Maximum setting Between 8.5 and 10.1.
(measured after
10 minutes
Minimum setting A minimum 0.2 lower than the
(measured after maximum reading taken but
10 minutes above 7.5%
Table 28 NG CO/CO settings
2
LPG Appliances
Output CO Reading
2
Maximum setting Between 9.8 and 11.1.
(measured after
10 minutes
Minimum setting A minimum 0.2 lower than the
(measured after maximum reading taken but
10 minutes above 8.5%
Table 29 LPG CO/CO settings
2
Example of a Natural Gas appliance reading:
• Maximum CO reading taken = 9.5%
2
• The minimum CO reading must be between 8.0% and 9.3%
2
(a minimum 0.2 lower than the maximum reading of 9.5%)
If the boiler fails the combustion test, check:
1. Air intake for restriction
2. Cleanliness of the heat cell, condition of the burner, plus blockages in
the condensate disposal.
7.7

CLEANING THE HEAT EXCHANGER

NOTICE: Gaskets and seals
▶ Replace the burner and electrode assembly gaskets
and the Flueway sump seal after cleaning the heat
exchanger.
Do not attempt the cleaning procedure unless new
gaskets and seals are available.
There is an optional tool available to assist in cleaning the
heat exchanger, part number 7 746 901 479
The following items will have to be removed to gain access to the heat
exchanger for cleaning:
▶ Lower the control panel into the service position.
▶ Remove the case.
Greenstar i System Compact ErP - 6 720 813 280 (2015/07)
reading must be at least 0.2 lower
reading.
2
CO Reading
Less than 200ppm
Less than 50ppm
CO Reading
Less than 200ppm
Less than 50ppm
▶ Disconnect electrical wires to the fan, ignition transformer, spark
electrodes, flue overheat thermostat, main heat exchanger
temperature sensor and flow pipe temperature sensor.
▶ Flueway
▶ Fan assembly
▶ Ignition transformer
▶ Spark electrode assembly
▶ Burner housing, burner and gasket
Refer to sections 7.8.10 to 7.8.14 for instructions on how to remove
the items to gain access to the heat exchanger channels so that the heat
exchanger can be cleaned

7.7.1 CLEANING THE SIPHON

1. Protect the controller from water ingress and disconnect the black
discharge hose from the wall frame connector.
2. Rotate the siphon body clockwise to release the bayonet connection.
3. Pull the siphon body down and away from the boiler.
▶ Empty the water and debris into a suitable container.
▶ Visually inspect the siphon to ensure that it is clean and free from
debris.
3.
Fig. 70 Cleaning the siphon
REFITTING THE SIPHON
▶ Fill siphon with 200 to 250 millilitres of water.
1. Push the siphon up onto the sump assembly until it fully engages with
the sump connection.
NOTICE: Do not use solvents, adhesive or lubricant
when pushing the pipe onto the rubber connector.
2. Twist the siphon to the left to secure the bayonet connection.
3. Push the black discharge hose, onto the wall frame connector, until
fully engaged.
SERVICE AND SPARES
2.
1.
45