Fujitsu hp's icing

[rbartlett]

hi guy's

last week we had a few fujitsu cassettes and the odd ducted system which would ice up occasionally. (about 6 in total) all seems to be okay butevery now and agian ice up and then later they would defrost normally.

One had about 50+ mm solid ice on the outdoor coil I defrosted it

when it was cleared the thing seemed to be fine and would defrost normally (the previous week the customer had defrosted another one by running on cooling -but when I was there no ice...)

any idea's as to why these should ice up occasionally then run fine..?
(noting that there is nothing wrong with them except a small hunch that they are overcharged....TBC)

cheers

richard

[chemi-cool]

Hi Marc.

Defrost problems, 95%, relate to a faulty outdoor coil sensor.

As Richard did not indicate other problems, I would change it and see if the problem will repeat itself.

From my experiance, 4 way valves, either work or not, any hitting on them to make them move, will get them stuck.

Good luck.

Chemi

[frank]

Are they on R407C?

I've had this happen before. Got to the outdoor unit at about 8 in the morming and found about 2" of ice build up with the ambient at about 5C. No outdoor fans running but the compressor was whirring nicely. Indoor area was nearly up to set point and no error codes were showing. Spoke to technical help who said that this was quite normal as the unit was "learning" the operating parameters and would then set defrost times automatically. On this unit there was a dip switch to increase the defrost frequency if required.

[Dave Goodings]

Richard Get a specialist like Marc to come to site I hear his rates are very reasonable and in SA they learn all about reverse cycle defrosts !!!!

[Mark]

Frank ,the outdoor unit setting adjusts the defrost duration .8,9,12 minutes cant remember which dip-switch it is though.

[rbartlett]

all systems on R22

don't see where the 'faulty sensor' can come into play as they are different models 2+3+1 and from different years '91 & '98

there is no fancy 'learning' with these fujitsu systems either..

I'm guessing that we are all just shooting in the dark as no one has come back with anything which specifically relates to fujitsu...

cheers

richard

[Mark]

Richard
On many models of fujitsu A/C the defrost is initiated by coil temperature and/or compressor run time.The defrost duration is governed by the set up.
Even the older models shared a similar operating principle.......

[Dave Goodings]

Sorry Marc I couldnt help myself I thought you would have a laugh, I know some of these smaller systems can be a nightmare are the probes fitted in the right location etc?

[rbartlett]

just to bring you back up to date..

went back with reclaim rig etc and new sensors (jic)

reclaimed and recharged,didn't fit the sensors as I wanted to try the 'charge' first-both running a-okay


i refer back to my original post...

"(noting that there is nothing wrong with them except a small hunch that they are overcharged....TBC)"


cheers

richard