Plumbing / boiler
Shower hot water fluctuates
Temperature fluctuations in the shower can come from the mixer, water flow, boiler or system pressure.
Possible causes
- faulty thermostatic or single-lever mixer
- deposits in boiler heat exchanger
- unstable pressure/flow on supply
- clogged filters
- boiler modulation issue
Useful information
- happens only at shower or also at other faucets
- boiler shows error or temperature fluctuates
- cold water pressure is stable
- there is a thermostatic mixer
Inspection
For a correct conclusion, flow, filters, mixer and boiler domestic hot water operation should be checked.