Joining the Renewable Heating Hub forums is completely free and only takes a minute. By registering you’ll be able to ask questions, join discussions, follow topics you’re interested in, bookmark useful threads and receive notifications when someone replies. When choosing your username, please note that it cannot be changed later, so we recommend avoiding brand or product names. Before registering, please take a moment to read the Forum Rules & Terms of Use so we can keep the community helpful, respectful and informative for everyone. Thanks for joining!
Error on Immersun – Error 8 Load Short Circuit
We've had a persistent error on our Immersun today – I've restarted it several times, and the cabling has remained untouched, so not sure what's causing it. No such error in the manual. Any thoughts anyone?
Error 8
LOAD SHORT-CIRCUIT
Check: Heater
Could it be telling me the immersion heater has stopped working?
Get a copy of The Ultimate Guide to Heat Pumps
Subscribe and follow our YouTube channel!
Having a short circuit would cause the output current to increase to a high level, hence the Immersun unit shuts down the output to protect both the unit and the external circuitry. The cause could be a short circuit within the wiring or the immersion heater, or possibly within the Immersun unit itself.
If you have a isolation switch between the Immersun unit and the immersion heater then switch this off and see if the fault clears. This would indicate that the fault is at the immersion heater or the wiring connected to it.
If the fault is still present then switch off the power supply to the Immersun unit and disconnect the output cabling. Switch the power back on to the Immersun unit and if the fault is cleared then the short circuit is on the wiring from the Immersun unit to the isolation switch, or the isolation switch itself.
If the fault is still present then the problem is within the Immersun unit.
@derek-m, I left the unit off overnight (disconnected from power).
I turned it on this morning with the immersion connector removed, so only the Immersun was starting up. Within 2 minutes the same is back. Looks like I'll have to send a message to Immersun.
Get a copy of The Ultimate Guide to Heat Pumps
Subscribe and follow our YouTube channel!
As an update to this, Immersun's customer support was excellent. I ran some diagnostics at our end and the error persisted. Immersun organised for the unit to be collected by DPD – a week later it was returned, and it's working perfectly. So the error was related to the Immersun unit, not the immersion heater.
Get a copy of The Ultimate Guide to Heat Pumps
Subscribe and follow our YouTube channel!
Yesterday, my Immersun screen started flashing with the same error message. 'ERROR 8. LOAD SHORT CCT, CHECK: HEATER.
Unfortunately my unit is 16months old and I have discovered is now out of warranty.
I contacted IMMERSUN, they say that is is unlikely to be the unit itself, and I should check the external equipment. I have checked the supply from the MCB @240v, I have checked the resistance of the load circuit from the (disconnected) plug at the Immersun and with the thermostat contact made, it is 20 Ohm which is correct for a 3kW heating element. Resistance to ground is 'OL' on my multimeter. What else could be externally wrong that might cause this to happen.
Any ideas would be greatly received.
Do you still get the fault when the immersion heater is disconnected or the thermostat contact is open? If the fault is still present, then it could be a cable fault or the Immersun unit itself.
@julesmp8 that’s not great news. We did a bunch of “tests” connecting and disconnecting the unit from the immersion. Throughout the process, we were in touch with Immersun, and they requested we send the unit back because there was a hardware issue, but they never disclosed what the problem was; contrary info to what they told you.
I would, however, work through Derek’s processes. He’s very good at getting to the root of the issue.
Get a copy of The Ultimate Guide to Heat Pumps
Subscribe and follow our YouTube channel!
Thanks for the info.
As mentioned I have checked all the wiring and I cannot find any issue which would suggest an external short cct.
I have also powered the unit up with the load connector disconnected inside the Immersun but the exact same fault appears. Immersun have provided me with a procedure that performs a Factory Reset of the unit but that doesn't help either.
It seems to me that the fault has to be inside the unit but at a starting price of £169 for testing/ repairing this negates the whole reason for fitting the unit in the first place - to save money !
@julesmp8 we did the factory reset too, which didn't help. I really like the Immersion units because they look really well built (far prefer them to the Solar iBoost) but there does sadly appear to be an issue with the units.
Get a copy of The Ultimate Guide to Heat Pumps
Subscribe and follow our YouTube channel!
Posted by: @editor@julesmp8 we did the factory reset too, which didn't help. I really like the Immersion units because they look really well built (far prefer them to the Solar iBoost) but there does sadly appear to be an issue with the units.
Did you get your faulty unit repaired? What was the fault?
Hi
So there appears to be only 2 options left available. Prepay Immersun £179, send the unit to them and hope they can fix it (they quote a 85 - 90% success rate; charging either way).
Buy something else to do the same thing.
Posted by: @derek-mDid you get your faulty unit repaired? What was the fault?
Yes, they repaired it. I enquired what the issue was but they said that they didn’t get a report from the repair team - it was clear they didn’t want to share what the cause was.
Get a copy of The Ultimate Guide to Heat Pumps
Subscribe and follow our YouTube channel!
- 27 Forums
- 2,545 Topics
- 59.3 K Posts
- 894 Online
- 6,832 Members
Join Us!
Worth Watching
Latest Posts
-
RE: Renewables & Heat Pumps in the News
@jeff hefty read… exhausted now, but will admit I skimm...
By Mars , 5 hours ago
-
Grant Aerona R290 15.5kw Heat Pump
Does anyone have the Grant Aerona 15.5kw heat pump and ...
By willow345 , 5 hours ago
-
RE: Grant 10kW versus Samsung 12kW - sizing dilemma with ECO4 installation
@tobyg - what has your experience been with the Grant 1...
By willow345 , 5 hours ago
-
No corrosion inhibitors detected in system fluid. No fr...
By phowardstutterheim , 6 hours ago
-
RE: Heat pump Surge protection
@transparent I do so appreciate your contribution on th...
By DavidAlgarve , 8 hours ago
-
RE: Daikin high temperature heat pump
@gajolos I heard back from Daikin, and they explained t...
By Mars , 11 hours ago
-
RE: Aerotherm 12+12kw cascade huge power utilisation
@editor This is really crazy. I can sort of understan...
By JamesPa , 19 hours ago
-
Or just add any further discussion to the other thread....
By cathodeRay , 20 hours ago
-
RE: NIBE Heat Pump Warranty: What's an Adequate Engineer Attendance Time?
@hughmark, great to hear. Fingers crossed that it’s sor...
By Mars , 1 day ago
-
RE: Samsung Gen 7 16kW Integrated unit Modbus monitoring
@johnnyb HI,I have an integrated unit with all componen...
By antonical , 1 day ago
-
RE: Solar Power Output – Let’s Compare Generation Figures
@papahuhu Ironical isn’t it? The last few days, the ‘Ag...
By Toodles , 1 day ago
-
RE: Setback savings - fact or fiction?
I answered that days back, I even provided a summary of...
By RobS , 1 day ago
-
RE: If a heat pump can only heat DHW to 50C then what? Issue with 18KW Heliotherm heat pump
I must say that this install is sounding more and more ...
By Mars , 2 days ago
-
RE: Who's your electricity provider and what's your tariff?
@chandykris Thanks, that’s a fair point and I agree th...
By Eliuccio , 2 days ago
-
-
RE: The law of unintended consequences....
Oh Thank you Major, I was just beginning to wonder wher...
By Toodles , 4 days ago
-
RE: Forum updates, announcements & issues
I know that the notifications are being delivered now w...
By Mars , 4 days ago
-
RE: Advice needed after a successful "leftfield" experiment.....
@pauli I have sent a direct message with the financial ...
By ChandyKris , 4 days ago
-
RE: Octopus Cosy 12 Heat Pump Regret: Incredibly Loud, Poor Heating & Constant Hum - Help!
Does it disappear when the heat pump is off? What abou...
By JamesPa , 4 days ago
-
RE: Fitting heat pump plumbing and pipes in advance?
Great tips, thanks. The PEX/Al/PEX option sounds much m...
By Jonatan , 4 days ago
-
RE: Struggling to get CoP above 3 with 6 kw Ecodan ASHP
Those control valves on the UFH manifold could be an is...
By Travellingwave , 4 days ago
-
RE: Daikin Altherma 3 LT compressor longevity question
Up to a point yes. However every heat pump (and every ...
By JamesPa , 4 days ago
-
RE: New Build ASHP Defects - Looking for Advice, Support & Shared Experiences
Is that a single pair only? If so it may be part if th...
By JamesPa , 4 days ago
-
@batpred, you’re quite right; it does work well. I don’...
By Majordennisbloodnok , 4 days ago


