MECH-02
Jandy · JXi 400,000 BTU Pool and Spa Heater with Digital Temperature Control
Calcium scale or corrosion has built up inside the copper heat exchanger tubes, reducing heat transfer efficiency and restricting water flow — symptoms include the heater taking much longer to heat the pool, high exhaust temperatures (SFS trips), and reduced water flow through the heater; scale buildup is caused by high calcium hardness (above 400 ppm), high pH (above 7.8), or high total alkalinity; a professional acid wash/descale of the heat exchanger can restore efficiency; maintain proper water chemistry (calcium 200-400 ppm, pH 7.2-7.6) to prevent recurrence; severe corrosion from low pH or aggressive water chemistry may require heat exchanger replacement ($500-1,500+ part)
Error MECH-02 on the Jandy JXi 400,000 BTU Pool and Spa Heater with Digital Temperature Control means: Heat Exchanger Scale or Corrosion. The top-ranked community fix is “Perform Deep Burner Tube Cleaning and Install Preventative Screens” (medium difficulty, ~45 min, DIY cost: $15-$30). 2 community-ranked fixes available below.
Published February 2026 · 2 fixes · pool heater
Content is based on manufacturer service documentation, community repair experience, and OEM technical bulletins. Always verify with your owner's manual.Learn about our editorial standards.
While many pool heater repairs can be done safely at home, consider hiring a qualified technician if:
Average professional repair cost for this issue: $120-$200.
pool_controller · 2 fixes
pool_filter · 2 fixes
pool_pump · 2 fixes
pool_heater · 2 fixes
pool_heater · 2 fixes
pool_pump · 2 fixes
The Jandy JXi 400,000 BTU Pool and Spa Heater with Digital Temperature Control has 8 other known error codes:
Error code MECH-02 also appears on 6 other Jandy models:
Ad Space — banner
Replace ADSENSE_PUBLISHER_ID in AdUnit.tsx
