R
52
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Rinnai · Tankless Water Heaters
Modulating gas solenoid valve signal abnormal.
Quick Answer
Error code 52 on your Rinnai Tankless Water Heaters means: Modulating gas solenoid valve signal abnormal.. This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
RE199iNRU199iNRUCS65iNV53e
Likely Causes
  1. Valve coil electrical issue
  2. Loose harness connection
  3. Control board signal fault
  4. Valve mechanical failure
How to Fix It
1
Do not continue cycling the unit repeatedly.
2
Have technician inspect valve harness and connector pins.
3
Measure valve coil resistance.
4
Replace gas valve assembly if out of spec.
5
Run combustion setup check after repair.
Pro Tip
This issue typically requires professional diagnosis. Attempting this fix without proper training could cause further problems.
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