- Heat pumps
- Air-to-water heat pump
H70
Panasonic H70 on an Aquarea heat pump: backup heater overload protection
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
Medium
Quick answer
On Aquarea units, H70 means the electric backup heater overload protection has tripped or its supply is missing. You can reset it from the controller, but Panasonic says to contact the installer for a full reset.
Safety first
Stop and check this first
- Panasonic states that service must be carried out by qualified personnel only and that you must not put fingers into the unit, as rotating parts may cause injury. When a code shows, turn the unit off and give the code to an authorised dealer.
Safe checks you can perform
- Reset from the controller
- Backup heater supply breaker
- Voltage at power supply 2 and thermostats
Leave these tasks to a qualified professional
- Do not attempt this professional task: Measure the supply before the heater
- Do not attempt this professional task: Thermostat reset with venting
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.
Measure the supply before the heater
What they doThe installer measures voltage at power supply 2 before touching the heater or its thermostats.
They must show youthe voltage measured at power supply 2.
In writingwhether the fault was supply or thermostat and what was corrected.
Thermostat reset with venting
What they doIf a thermostat tripped, the installer resets it and checks no air remains around the heater.
They must show youthe venting done and the heater running without H70.
In writingthe thermostat reset and the test with electric backup running.
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.
Reset from the controller
- Who:
- you.
- How:
- reset the code from the controller as Panasonic's user guide describes.
- Result that matters:
- Panasonic warns the system will appear to run normally, but a full reset by the installer is needed.
- If the code clears:
- the electric backup is still unverified; tell the installer anyway.
- If it returns as soon as backup is called:
- the protection is still open or the supply is missing.
- Evidence to keep:
- a photo of the code and a note of when backup was called, for example on very cold days.
Evidence: Panasonic Aquarea user guide for Bi-Bloc, Monobloc and All in One, C, D and E series · Panasonic Aquarea installation guide 1.2, Monobloc solutions H and J generation
Backup heater supply breaker
- Who:
- you, only looking at the consumer unit.
- How:
- check whether the breaker feeding the heat pump backup heater is off.
- Result that matters:
- Panasonic says H70 also shows when power supply 2 is missing.
- If it is off:
- switch it on once; if it trips again, leave it and call an electrician or the installer.
- If it is on:
- a visible cut is ruled out; the installer measures the voltage.
- Evidence to keep:
- a photo of the consumer unit.
Evidence: Panasonic Aquarea user guide for Bi-Bloc, Monobloc and All in One, C, D and E series · Panasonic Aquarea installation guide 1.2, Monobloc solutions H and J generation
Voltage at power supply 2 and thermostats
- Who:
- the installer.
- How:
- they measure the voltage at power supply 2; if correct, they check whether a heater thermostat has tripped, reset it and make sure the heater is free from air.
- Result that matters:
- voltage present or absent and the state of each thermostat.
- If the voltage is wrong:
- the supply is the cause; the electrical circuit is corrected.
- If voltage is correct and a thermostat is open:
- overheat is confirmed; the heater must be vented before closing the job.
- Evidence to keep:
- a job sheet with the measured voltage and the thermostat reset.
Mains voltage on the backup heater. Installer or electrician only, with the supply isolated.
Evidence: Panasonic Aquarea user guide for Bi-Bloc, Monobloc and All in One, C, D and E series · Panasonic Aquarea installation guide 1.2, Monobloc solutions H and J generation
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
- Heat pumps
- Brand
- Panasonic
- Product type
- Air-to-water heat pump
Known code variants
- Aquarea H70
- Panasonic Aquarea H70
- Panasonic heat pump H70
What it means
Panasonic explains that the internal backup heater has overheat thermostats; if one trips and becomes open circuit, H70 occurs. It also shows when power supply 2, which feeds the heater, is missing. It only appears when the backup heater is activated. The installer flowchart separates incorrect voltage at power supply 2 from a tripped thermostat, which is reset while making sure the heater is free from air. The code does not prove the heater is broken.
Warnings and stop conditions
- Mediumsource verified
Panasonic states that service must be carried out by qualified personnel only and that you must not put fingers into the unit, as rotating parts may cause injury. When a code shows, turn the unit off and give the code to an authorised dealer.
Evidence: Panasonic Aquarea user guide for Bi-Bloc, Monobloc and All in One, C, D and E series
Symptoms and causes
Probable causes · in order
- Power supply 2 missingCommon
If the heater supply breaker or cable is off, H70 shows when backup is called. Measuring voltage at that supply separates it.
Evidence: Panasonic Aquarea user guide for Bi-Bloc, Monobloc and All in One, C, D and E series · Panasonic Aquarea installation guide 1.2, Monobloc solutions H and J generation
- Overload thermostat trippedCommon
One of the heater's internal thermostats opened on overheat. Panasonic says to reset it and make sure the heater is free from air.
Evidence: Panasonic Aquarea user guide for Bi-Bloc, Monobloc and All in One, C, D and E series · Panasonic Aquarea installation guide 1.2, Monobloc solutions H and J generation
- Air around the heaterPossible
With air around the heater it overheats and trips the thermostat. It is the step Panasonic adds after the reset.
Evidence: Panasonic Aquarea user guide for Bi-Bloc, Monobloc and All in One, C, D and E series · Panasonic Aquarea installation guide 1.2, Monobloc solutions H and J generation
Virtual technician
Does H70 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
Panasonic Aquarea user guide for Bi-Bloc, Monobloc and All in One, C, D and E series
Panasonic · 2014 · manual
- 2
Panasonic Aquarea installation guide 1.2, Monobloc solutions H and J generation
Panasonic · 2021 · manual
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