Fujitsu AUY 30 Failing to Heat

[CoolKids]

Hi All

Problems with a newly installed AUY 30 Fujitsu Cassette 240v Heat pump

After the installation and commissioning of the system we found that the off coil temp in heating mode was about +21 it didn't want to go any higher.
The suction pressure was around 110 psig liquid line around the same.

Please could anyone help as the store manger is rather cold today.

[philjd26]

bbbbuurrrrr.....ithe unit turned on? is it in heat mode?is the compressor running? is the compressor driving the right way?

rgrds phil

[CoolKids]

Hi Phil

Yes its doing all of that.

[CoolKids]

Hi Phil

Do you think I would have asked for help before checking the obvious!

[Brian_UK]

Has the reversing valve changed over correctly, have you tried it with a magnet?

What is it like in cooling mode?

Are the service valves fully open?

[CoolKids]

HI Brian

The service valves are fully open

Its trying to heat but ends up going on defrost before it reaches its target temperature.

[Brian_UK]

Could there be a problem with the coil/air temperature sensors ? Either faulty or displaced from their holders.

[CoolKids]

Hi Brian

Its definetly food for thought. Will try tommorrow.

Thanks

[Andy AC]

Is it just a single system or were there more installed at the same time? - crossed pipes / wiring maybe, we've all done it before.
You also mentioned that the suction and liquid pressures were the same - compressor running but not pumping? Was there any movement on the gauges when you started the compressor?

Andy

[paul_h]

Is it just a single system or were there more installed at the same time? - crossed pipes / wiring maybe, we've all done it before.
You also mentioned that the suction and liquid pressures were the same - compressor running but not pumping? Was there any movement on the gauges when you started the compressor?

Andy

You wouldn't be able to even get the suction or liquid pressures.
I don't think these have a schrader on the condenser, (which would be the evaporator in heat mode), so on heat you couldn't get the suction anyway.
The suction service valve on heat mode would be showing the discharge pressure.


What's the full model code?
What does it do on cooling?
Is the condenser actually icing up and going on defrost legitimately, or is the condeser clear of frost and ice and it going on defrost for no reason?

edit: Use test mode to get it to run on cooling if it's a low ambient, - if it's the wall controller with an orange start button and flip down lid, hold down mode and fan button to get test mode.

[CoolKids]

Hi All

Sorted the problem

I removed the precharge supplied with the unit and re commissioned with fresh R410A refrigerant.

Running pressures and amps all okay

Working fine

[Brian_UK]

Good to hear.

[nike123]

Hi All

Sorted the problem

I removed the precharge supplied with the unit and re commissioned with fresh R410A refrigerant.

Running pressures and amps all okay

Working fine

With my experience of 1500 personaly mounted Fujitsu units, I never have problem with factory charge! I will carefully monitor this unit to rule out charge problem.

[Danny11]

Hi pal

If your ever stuck again try www.airconsquad.co.uk
There pretty good on fujitsu tech work.

Cheers
Danny

[The Viking]

With my experience of 1500 mounted Fujitsu units, I never have problem with factory charge! I will carefully monitor this unit to rule out charge problem.

OK,
What we have found quite frequently on Fujitsu units is that when you pressure test them, the valves are letting by, thus mixing OFN in to the outdoor unit's factory charge.......
The units then doesn't seem to run to well with non condensables in them

[Grizzly]

Viking what sort of pressures are you applying during a pressure test?
Incidently what sort of pressure would you apply for a 407a system guys?
Cheers grizzly

[The Viking]

Now you got me....

I don't do installs any more.

I will ask some of the guys tomorrow.....

(Sorry)

[nike123]

OK,
What we have found quite frequently on Fujitsu units is that when you pressure test them, the valves are letting by, thus mixing OFN in to the outdoor unit's factory charge.......
The units then doesn't seem to run to well with non condensables in them

After every instalation, I check with soap solution every connection and valve cap, and I don't see any reason to pressure test unit after that. It is common knowledge that every 3way and 2way valve on split systems leaks when they are frequently used, and because of that, all off them have valve cap. After every manipulation of valves, it is ( at least, for me) obligatory to test valve cap with soap solution.

[Danny11]

Hi brian

I have spoke to webram a while back,its ok because weve put a link on our website of RE.

Cheers
Danny

[Brian_UK]

Hi brian

I have spoke to webram a while back,its ok because weve put a link on our website of RE.

Cheers
Danny

OK Danny, my apologies, post restored.

[The Viking]

After every instalation, I check with soap solution every connection and valve cap, and I don't see any reason to pressure test unit after that. It is common knowledge that every 3way and 2way valve on split systems leaks when they are frequently used, and because of that, all off them have valve cap. After every manipulation of valves, it is ( at least, for me) obligatory to test valve cap with soap solution.

Nike,
First of all, good engineering practices dictates that all installations are pressure tested......
Secondly, I believe that you misunderstood the issue.
These "problem" valves are leaking internally(when shut), from the pipe work in to the condensor, you will never find that with soapy water on the outside.

[nike123]

Nike,

Secondly, I believe that you misunderstood the issue.

That's right!

[sinewave]

We've had leaking valves on Fujitsu units efore now!


I think the OFN mixed with the Refrigerant is a likely cause too!

[nike123]

Nike,
First of all, good engineering practices dictates that all installations are pressure tested......

When you installing compact split systems with flexible (annealed) coper pipes you don't need to pressure test it (because there is no brazing involved).
It is sufficient to vacuum it below 400 microns, then isolate vacuum pump, and if vacuum after 10-15 minutes stays below 400 microns you could be pretty sure that there is no leak.
Than, after you let refrigerant into pipes and indoor unit, you simply test flare connections with soap solution after you put unit to heating mode.
This is my method!

[The Viking]

No comment.

[paul_h]

When you installing compact split systems with flexible (annealed) coper pipes you don't need to pressure test it (because there is no brazing involved).
It is sufficient to vacuum it below 400 microns and if vacuum after 10-15 minutes stays below 400 microns you could be pretty sure that there is no leak.
Than, after you let refrigerant into pipes and indoor unit, you simply test flare connections with soap solution after you put unit to heating mode.
This is my method!

Just be wary of the leaking valves, or you'll vac out the condensing unit. I've seen it happen about a dozen times. When removing the service valve flare cap, see if theres any pressure behind it. Let the pressure out then refit the cap loosely and see if there's any bubbles around it before installation to see if the valve holds.

[wombat]

Hi All

The Australian Fujitsu web site shows the minimum pipe length to be 5m. If the units are located closer together there may be a heat or cool problem with operating pressures.

As I plan to install a ducted Fujitsu next week where the pipe length may be less than 5m, I'm keen on knowing how to proceed. Remove refrigerant or have ugly loops of refrigerant pipes.

My theory on flare fittings is that a good vacuum could be achieved as the fittings will forced together, but then leak refrigerant when pressure is applied as pressure will obviously push the copper flare away from the brass fitting.

Anyone agree or is my theory wrong!

Gary

[paul_h]

Hi All

The Australian Fujitsu web site shows the minimum pipe length to be 5m. If the units are located closer together there may be a heat or cool problem with operating pressures.

As I plan to install a ducted Fujitsu next week where the pipe length may be less than 5m, I'm keen on knowing how to proceed. Remove refrigerant or have ugly loops of refrigerant pipes.

My theory on flare fittings is that a good vacuum could be achieved as the fittings will forced together, but then leak refrigerant when pressure is applied as pressure will obviously push the copper flare away from the brass fitting.

Anyone agree or is my theory wrong!

Gary

How can a ducted be less than 5m.
Don't tell me you are putting the o/u high up on the wall and the indoor right above the eaves?
It's pretty easy to get 5m pipe runs on a ducted, 2m up the wall, 4-6 metres accross the ceiling to the midlle and highest point of the ceiling.
The pipe length is more for heating, too short a pipe run and it will be overcharged, with gas noises heard from the indoor unit. It doesn't matter so much on cooling because of the suction accumultors and condenser fan control. It's hard to balance by removing refrigerant, you may end up with an undercharge in cooling, still get gas noises in heating, and it could void the warranty.
How can you end up with ugly extra coiled pipes when it's a ducted unit that goes through the ceiling anyway?

Flares leak because they are loose, rough or burred, so they'll leak under vacuum. But there's no point saying it has a vacuum so it doesn't leak, without a accurate vacuum gauge getting a 'vacuum' tells you nothing, you need to be able to measure it in microns, not your service gauges.

[wombat]

Paul

Thankyou for your reply. The ducted unit will be in an office building with the condenser on the wall and the indoor about 2m on the other side. The current York ducted is to be replaced with a larger Fujitsu.

I agree, a digital vacuum meter should indicate a problem with a flare. The flare nut problem occurred many years past when digital vacuum meters were not common.

Gary

[nike123]

Just be wary of the leaking valves, or you'll vac out the condensing unit. I've seen it happen about a dozen times. When removing the service valve flare cap, see if theres any pressure behind it. Let the pressure out then refit the cap loosely and see if there's any bubbles around it before installation to see if the valve holds.

That's good advice!

[nike123]

Viking what sort of pressures are you applying during a pressure test?
Incidently what sort of pressure would you apply for a 407a system guys?
Cheers grizzly

You need to now maximum allowable pressure of components exposed to test pressure and do not exceed that pressure.
I test Fujitsu split-systems with R407 (also R22) with 27 bar.

[ozairman]

Late entry here but a few tips from someone who knows
If you are taking the flare nuts off the service valve don't be an oaf and just crank on the flare nut without supporting the body of the valve by countering the force you apply with another spanner on the cap of the service valve. Fuji's early R410A offerings did seem to be bit funny in this area but only if you were brutal and I have never had it occur myself. But the later ones if you look closely seem to have about twice as much brass in the body of the service valve as the earlier ones.

As far as pressure testing if you don't exceed the standing pressure inside the outdoor unit then there is no chance of blowing your OFN into the outdoor unit is there

[paul_h]

That's only 1500kpa at best, while the joins have to be good enough to seal at 3500kpa on heating mode.

[teamnicknz]

With my experience of 1500 personaly mounted Fujitsu units, I never have problem with factory charge! I will carefully monitor this unit to rule out charge problem.

We are constantly having problems with fujitsu units under or overcharged, yesterday i pulled 150grams out of a ASTA18 that should of had 1150grams and alot of ASTA24 only having 1000grams in them. Don't know if we got a bad batch of them.