- Boilers
- Electric water heater
EoF
A. O. Smith EoF on a hybrid heat pump water heater: condensate pump failure
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
Medium
Quick answer
On an A. O. Smith hybrid water heater with the accessory condensate pump, EoF means that pump has failed. Check that it is plugged in and has power, check the breaker or fuse and any GFCI, and look for a blocked outlet tube.
Safety first
Stop and check this first
- A. O. Smith forbids discharging the condensate lines into the metal drain pan. If condensate is not draining, check for water on the floor and tell the installer.
- A. O. Smith warns that this heater can make water hot enough to cause severe burns instantly; it is factory set to about 140 °F (60 °C), where a serious burn takes less than 5 seconds. It recommends thermostatic mixing valves.
Safe checks you can perform
- Condensate pump power
- Pump outlet tube
- Control wires and pump
Leave these tasks to a qualified professional
- Do not attempt this professional task: Control connection and pump check
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Control connection and pump check
What they doThe technician checks the control wire connections and, if they are fine, replaces the condensate pump, following A. O. Smith's sequence.
They must show youthe condition of the control connections.
In writingthe cause, the pump replaced if any and that EoF did not return after the test.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Condensate pump power
- Who:
- you.
- How:
- check that the condensate pump is plugged in and has power; check the breaker or fuse and, if fitted, the GFCI for that outlet.
- Result that matters:
- this is the first check A. O. Smith gives for EoF.
- If it was unplugged or the protection had tripped:
- restore it and watch whether EoF clears.
- If it has power and EoF remains:
- go on to the outlet tube.
- Evidence to keep:
- a note of what you found and the time.
Evidence: A. O. Smith Hybrid Electric Heat Pump Water Heater installation instructions and use and care guide
Pump outlet tube
- Who:
- you.
- How:
- follow the condensate pump outlet tube by eye and look for kinks, pinches or dirt at its end, without taking the pump apart.
- Result that matters:
- A. O. Smith says to check whether that tube is blocked.
- If it is kinked or clogged at the end:
- correct it and watch whether EoF clears.
- If it is clear and EoF remains:
- the control wires and the pump remain, for the technician.
- Evidence to keep:
- a photo of the tube.
Evidence: A. O. Smith Hybrid Electric Heat Pump Water Heater installation instructions and use and care guide
Control wires and pump
- Who:
- a qualified technician.
- How:
- with power off, checks the control wire connections between the condensate pump and the heater; if they are fine, replaces the pump.
- Result that matters:
- whether the control connection is sound.
- If the connection was loose:
- fixing it confirms the cause if EoF does not return.
- If a new pump does not fix it:
- A. O. Smith asks for a qualified technician to service the heater.
- Evidence to keep:
- a job sheet of what was checked and the pump reference if replaced.
Connections inside the heater next to 240 V wiring. Qualified technician only.
Evidence: A. O. Smith Hybrid Electric Heat Pump Water Heater installation instructions and use and care guide
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Boilers
- Brand
- A. O. Smith
- Product type
- Electric water heater
Known code variants
- A. O. Smith EoF
- A.O. Smith EoF error
- AO Smith EoF
- E oF
- EOF
- Error EoF A.O. Smith
What it means
A. O. Smith links EoF to a condensate pump failure, only if that accessory pump is installed. The heat pump produces condensate that drains through the condensate lines; where no adequate drain is available a condensate pump is used. The manufacturer's sequence is: pump power, blocked outlet tube, control wires and, last, replacing the pump. The code does not say at which point the fault lies.
Warnings and stop conditions
- Mediumsource verified
A. O. Smith forbids discharging the condensate lines into the metal drain pan. If condensate is not draining, check for water on the floor and tell the installer.
Evidence: A. O. Smith Hybrid Electric Heat Pump Water Heater installation instructions and use and care guide
- Highsource verified
A. O. Smith warns that this heater can make water hot enough to cause severe burns instantly; it is factory set to about 140 °F (60 °C), where a serious burn takes less than 5 seconds. It recommends thermostatic mixing valves.
Evidence: A. O. Smith Hybrid Electric Heat Pump Water Heater installation instructions and use and care guide
Symptoms and causes
Probable causes · in order
- Pump without powerCommon
A. O. Smith asks first for a check that the pump is plugged in and has power, and that the breaker or fuse and GFCI are fine. It can be seen without tools.
Evidence: A. O. Smith Hybrid Electric Heat Pump Water Heater installation instructions and use and care guide
- Blocked outlet tubePossible
This is the manufacturer's second check. A kinked or clogged tube stops the water from draining.
Evidence: A. O. Smith Hybrid Electric Heat Pump Water Heater installation instructions and use and care guide
- Control wires or the pump itselfPossible
If power and tube are fine, A. O. Smith has the control connections checked and, if it persists, the pump replaced.
Evidence: A. O. Smith Hybrid Electric Heat Pump Water Heater installation instructions and use and care guide
Virtual technician
Does EoF still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 1
A. O. Smith Hybrid Electric Heat Pump Water Heater installation instructions and use and care guide
A. O. Smith · 2015 · manual
Was this entry useful?