Technical data

5 Troubleshooting Thermo 230 / 231 / 300 / 301 / 350
502
Heater operation stops because heat exchangers
connected do not dissipate enough heat.
Rate of flow too low, because
• air in heater, in heat exchangers or in system
sections.
• cocks (flow regulator) throttled, contaminated or
closed.
• contamination in system, e.g. in areas of restricted
flow.
• circulation pump rate of delivery insufficient (air in
pump housing).
wrong sense of rotation – check wiring colors
(black + / brown –).
• not enough anti-freeze.
• excessive system resistance (especially high when
cold).
• circulation pump defective.
Heat exchanger dissipate not enough heat,
because
• air in heat exchangers or in system sections.
• contaminated heat exchanger surfaces (external).
• insufficient air intake or exit.
• fan: rate of delivery low / wrong sense of rotation /
resistance too high.
• too much anti-freeze.
• heat exchanger of too low capacity.
Rough calculation of rate of flow
heat flow [kW] acc. to ident. label
Rate of flow in [l/h] = x 860
temperature difference ∆t in [K] or [°C]
measured between heater water inlet and outlet
(e.g. with contact thermometer)
Fault in fuel supply
No fuel delivery to heater. • fuel tank empty.
• kinked, closed, contaminated or leaking lines.
• paraffin deposits or water captured in fuel filter or fuel
lines.
• vent in tank clogged.
• fuel lines interchanged.
• fuel filter contaminated.
• fuel screen in pump contaminated.
Fig. 501 General Fault Symptoms (Sheet 2 of 3)
Symptom Probable Cause