ALUTHERM
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Boilers 54
ALUTERM A 170 - 300
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Installation, user and service manual
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instructions for user
Heating
Alutherm A 170 - 300
9.1
Service-maintenance table
When commissioning/inspecting the boiler CO2, CO, T flow, T return, ΔP air pressure switch and Psyphon pressure switch must be measured and the
measured values must be written down in the table below.
Measure these values when the boiler is in equilibrium at maximum load (also see chapter 5.5). Repeat for minimum load.
During annual inspection and maintenance, we advise to measure and write down these values also and compare them to the previous values and
analyse any change.
At the factory the maximum load of the boiler was measured within 5% tolerance from the nominal load.
In the field the load can decrease due to increased resistance in the boiler, the air inlet or the exhaust outlet or due to malfunctioning of the fan or
other causes.
At maximum load the installation should be designed for nominal ΔT of 15 K to 20 K. When the ΔT is higher than 25 K, the boiler cannot continue at
maximum load anymore and will start to modulate because water flow through the boiler is insufficient.
T flow and T return can be read in “info mode” on the display (see 5.4 diagnostics) Valves, malfunctioning pumps, dirt, corrosion products from the
installation, dirty filters etc. can have negative impact on water flow through the boiler.
Before ignition the boiler control checks ΔP aps during prepurge. During burner operation this check will be carried out. If the value decreases
over successive years, this could indicate a problem e.g. malfunctioning of the fan, dirty air inlet, dirty burner, dirty heat exchanger or dirty exhaust
system.
Syphon pressure (P sps) should be lower than the maximum allowable flue resistance.
If P sps is too high (> 8,3 mbar), the boiler will be stopped.
In this case the exhaust system may be blocked.
