Hold 27 Flame rod shorted to ground

What the control is telling you

The flame sensing circuit sees a dead short to ground. A short to ground can also show up as a flame circuit timeout (Lockout 113).

Applies to: Trinity Tft60, Tft85, Tft110, Tft154, Tft201, Tft285, Tft340, Tft399

Likely causes

• Flame circuit shorted to ground (zero-ohm short shows as this code, high-resistance shorts show as Lockout 113)
• Blocked condensate drain flooding the burner area
• Outside voltage present on the R or CH terminals
• 4-20 mA input above 21 mA

Test and repair steps

1. Make sure the condensate drain and trap are not blocked
2. Confirm no outside voltage is applied to the R and CH terminals
3. If a 4-20 mA signal is used, keep it at or below 21 mA

Models that show this code

13 models in Trinity Tft

Other codes on the same units

• Hold 25 Internal fault: Spark voltage changed too much during flame sensing time
• Hold 26 Internal fault: Static flame ripple
• Hold 26 Internal fault: Static flame ripple
• Hold 27 Flame rod shorted to ground
• Hold 28 Internal fault: A/D linearity test fails
• Hold 28 Internal fault: A/D linearity test fails
• Hold 29 Internal fault: Flame bias cannot be set in range
• Hold 29 Internal fault: Flame bias cannot be set in range