Slant/Fin
Domestic Hot Water Priority / Control or Flow Issue
Boiler runs but domestic hot water is insufficient or fluctuates (on combi or indirect systems)
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Faulty DHW sensor, Stuck 3-way diverter valve on Slant/Fin combi boiler, Scaled indirect tank coil, Incorrect DHW flow rate
How to Fix / Troubleshooting
Safety: Turn off power and water supply before working on DHW components.
Steps:
- 1. Check DHW demand: Ensure the boiler recognizes hot water demand (DHW icon or indicator on control).
- 2. Inspect 3-way valve (combi): Listen for valve movement when hot water is turned on. If stuck, the valve may need cleaning or replacement.
- 3. Indirect tank: For systems with an indirect tank, verify the tank aquastat is set correctly and calling for heat.
Professional service: A technician should test the DHW sensor, descale the coil if needed, and verify proper flow and control operation.
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Repair Difficulty
Hard
4/5
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