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seanw5055
20-11-2007, 12:02 PM
I have a Daikin E series split system (FTX935EVMA) It has been working fine since install (9 months) and suddenly it has constant erratic airflow surges when set to cooling mode. The airflow fluctuations occur about 15 minutes after turning it on. I thought it might be a fan speed problem or a power surge problem but the fan runs perfectly and consistently when not on cool mode. I dont know why this has suddenly happened or what may be causing it. The installer has no idea. Any theories would be a great help. Thanks Sean

expat
20-11-2007, 08:37 PM
Is this definately only happening in cool mode? Not in dry, heat or fan-only mode. Does it happen in auto mode when the unit is cooling?

Also try cool mode until the fluctuation starts then switch to fan-only to see if it goes back to normal or keeps fluctuating.

Brian_UK
20-11-2007, 10:04 PM
If the fan speed is set to 'auto' then the fan speed could be changing due to the temperature.

seanw5055
21-11-2007, 06:44 AM
Yes it only does it on cool which is why its got me stumped. When i switch from cool to fan only the problem stops. The Daikin techs have also inspected the problem and cant explain.

Loops
21-11-2007, 10:43 AM
First off I'm no Daikin expert so unsure of what safety mechanism they have.

You say the problem only occurs in cool mode so I'm wondering if over-condensing is your problem causing the evaporator to drop in temperature in turn initiating the frost prevention mechanism in the indoor unit. There maybe some sort of fan speed change involved with this - there is on the kit I'm used to.

Check your suction pressure \ evaporating temperature is correct, if low check;
1. Gas charge
2. If system has an outdoor fan speed controller and if so is it set up correctly.

As a temporary measure you could try blanking off part of the condenser inlet (about 50%) to see if that brings up the back pressure.

My thinking is that recent here in UK the ambient temperatures have dropped off quite dramatically over the last week or so.

Good luck

Loops

Loops
21-11-2007, 10:45 AM
Sorry should have added that if this system has an evaporator temperature sensor check that that's not giving a false readingto the circuit board.

Loops

seanw5055
23-11-2007, 01:26 PM
Thanks alot. Your info should help

frank
23-11-2007, 03:20 PM
Does the same symptoms occur if the fan is set to fixed speed and not 'auto' ?

Are any fault lights showing - flashing green led?

Have you interrogated the unit via the remote to see if any fault codes are there, such as A6.

Have you checked the calibration of the suction thermistor?

Here's the A6 fault troubleshooting guide (http://www.eatlime.com/download.lc?sid=09964318-eae5-102a-aaa7-0030488882b4)for the FTX wall mount