13 | P a g e
If iR boiler, pump has started and flow switch has made, then the flow has dropped out causing the flow switch to
connection to break. Usually, system related.
1. Check the pump for air and vent the system if required.
• Use the boiler air purge to assist by turning off the power at the fused spur for 5 seconds and
then re-establish the power.
2. Check external pump operating properly/strong enough.
3. Check auto air vent is operating correctly and not contaminated with sludge.
4. Check all isolation valves on boiler and system are open.
5. Check system design.
6. Check system for blockages.
7. To check the flow switch, disconnect it from the boiler and using a multimeter across the connections, check
for continuity when making the switch and OL when switch breaks. Only replace the flow switch when all
the above has been checked and confirmed.
154 Description: Flow temp increases too fast and high ∆T.
Cause: System flow, pump, or sensor fault.
1. Check the system for an external heat source such as solar which may affect the return temperature.
2. Confirm flow and return temperatures using the A menu, A0 & A1.
3. Check T1 and T2 resistances in line with temperatures from flow and return temperatures found on page 67.
• Take resistances at the PCB connector X4, pins 1&2 (T1) and 3&4 (T2). This checks the wiring
harness continuity and connectors at same time.
• Check wiring connectors are not loose or corroded.
• Disconnect the connector from PCB to ensure no additional resistances are given through the PCB.
• If readings incorrect, take resistance reading direct from sensor & replace sensor or wiring harness
as required.
• Note sensors may need cleaning and not always replaced.
To Next Page
Loading...
Need help?
General
