Daikin ceiling aircon unit

[u587162]

I have a commercial premises and my ceiling Daikin aircon unit which was there when we bought the business, does not heat the reception area very well then my staff always complain every winter that it’s still cold.

We service it every year. The engineer seems to think it’s going into defrost mode because the unit simply stop operating. By that I mean it stops blowing out warm air or blows cool air (not cold air) after being on for about 20 min, maybe more.

We set it to heat mode and set the temp to about 25/26 degrees when the display thing shows the room temp is about 15 or 17 degrees.

Am I right in thinking that we can’t control the actual heat temperature coming out of these units only the heat setting of the room?

I attach a pic of the display which shows the model of the unit although Daikin support on the phone (absolutely rubbish May I add - waited 45 min to answer and he couldn’t spend more than a few mins talking to me as he said he had other calls waiting - had the same issue last year). It also shows an error code which I have googled but I’m wondering if this is the issue because the error code was not there previously but we’ve had this issue for years where the unit goes quiet or off and it’s freezing cold.

What weird is that in the evening when all the staff have left, I sit in the same area and it’s toasty warm and the unit doesn’t go off like it does during the day so I’m wondering if it’s a setting thing?

 

[Harry Bloomfield]

We service it every year. The engineer seems to think it’s going into defrost mode because the unit simply stop operating. By that I mean it stops blowing out warm air or blows cool air (not cold air) after being on for about 20 min, maybe more.

Check the outdoor unit, when this happens, if it's all iced up, then it's doing it's best, but it's best is not good enough - you need to wait for it to defrost.

Perhaps, during the day, doors are opened and closed frequently, letting the warm air escape, so it has to work too hard. In the evening, doors remain closed, so the unit is able to cope?

 

[jj4091]

Taken from Google search Don't know if it wil help





L8-02 indicates an Electronic Thermal 2 error in the outdoor unit, specifically pointing to a severe overload current in the compressor for a short duration.



Meaning of Error Code L8-02

The L8 error code family generally relates to inverter compressor issues or overload protection activation. The specific sub-code L8-02 in a SkyAir or VRV system implies:

• Overload current flowed into the thermal protection device for approximately five seconds.
• The current was close to the locked-rotor current of the compressor motor.

Possible Causes

The L8-02 error is typically caused by one of the following issues in the outdoor unit:

• Closed Stop Valve: The stop valve in the refrigerant line might be closed, preventing proper refrigerant flow.
• Disconnected Wiring: The wiring in the compressor motor may have a disconnection.
• Compressor Damage: The compressor itself might be damaged or seized.

Troubleshooting Steps

To diagnose and resolve the issue, a qualified HVAC technician should perform the following checks:

1. Inspect Stop Valves: Ensure that all refrigerant stop valves are fully open.
2. Check Wiring Connections: Verify the connections of the wiring in the compressor motor and the outdoor unit's PC board.
3. Examine the Compressor: A professional should inspect the compressor coils and shaft for issues like seizure or damage.
4. PC Board Inspection: If the wiring and compressor appear fine, the outdoor unit's PC board may need replacement.

Caution: Troubleshooting electrical and refrigerant systems requires specialized knowledge and tools. It is recommended to contact a professional Daikin service provider for repair, as attempting DIY repairs without proper expertise can be dangerous and may void warranties. You can find detailed support and service options on the official Daikin website or by using their local service tools.

 

[u587162]

Yes thanks I did search that error code before posting a few days ago but as this problem has been ongoing for a few years without that error code, I’m not sure if that is/was the issue.

The problem is that the outdoor unit is on the room which is hard to access without permission from the landlord as well.

I’ve tried to figure out a pattern of when it stops blowing warm air but I can’t pin point anything. Sometimes we go through quiet periods during the day when the door is not opened yet it still stops blowing warm air.

 

[jj4091]

Obviously it is an issue now and your engineer won't be able to do anything else until he has rectified that problem

 

[u587162]

Does anyone know what the icons mean on the display. It shows the circled icons when the system shuts off.

 

[flameport]

Those are defrost mode, during which it will not provide any heat.

If it's going into defrost mode all the time, the outdoor unit is either clogged with dirt or it's been located incorrectly, meaning it's in an area with walls on all 4 sides and a floor/surface below, which will trap cold air.

 

[u587162]

Thanks. It's located on a flat roof with other outdoor units but not surrounded by walls. Has been installed there for many years before I bought the business.

 

[u587162]

Those are defrost mode, during which it will not provide any heat.

If it's going into defrost mode all the time, the outdoor unit is either clogged with dirt or it's been located incorrectly, meaning it's in an area with walls on all 4 sides and a floor/surface below, which will trap cold air.

Has this anything to do with the error messages?

 

[Harry Bloomfield]

Has this anything to do with the error messages?

Not an expert, but.... The error messages, seem to suggest the outdoor unit is icing up. Outdoor units, need good air flow around them, so they can 'suck' warmth from that air. If they cannot get enough fresh air flow, they freeze up. If the unit is blocked in by other units, or surrounded by walls, then it might not be able to 'suck' enough air flow.

If it's an old outdoor unit, another possibility, is that the atmosphere has attacked the thin alloy fins, drastically reducing it's efficiency, or it is choked with dirt.

The only way to find out what the issue is, it to have an engineer investigate it.