strange behavior of the outdoor unit

[Nesey]

Good day!
What could be caused by the following behavior of the outdoor unit.
When you turn on the heat after reaching the desired temperature, it "falls asleep". While there are no questions. But his "awakening" raises questions. Three questions on three issues:
1. First, it produces high-pitched hissing sound. (The tubes had already cold.) Question
2. Then the fan starts to gain momentum so quickly is going to take off weekdays. And for a time worked to the limit. With a roar, howl and tryaskoy.Question
3. Begins to move cool air instead of warm (from int. Unit). Question
Then again, is the warm air, the room warms up, the external power again, "sleeps" until the next terrible awakening.
Sorry. Google translation.

[cooldude]

What is the make and model of the unit is it vrv or split

[Nesey]

Split. Carrier 42LUVH026K/38LUVH026K. Invertor.

[Nesey]

Strange, where hiss (very loud, is strictly at the beginning of each cycle, 5 times a night)?
I wonder why the tube cooled ***** line, it's an inverter? That is the break he needs to work on reduced power, but to work and not sleep.
Why the fan to accelerate to a speed that is close to the outer block bouncing?

[JoeAT50A]

Incoming power supply voltage any abnormality found?
Or outdoor fan and compressor are dying?
If NO, Carrier start-up program may have some bugs. Obviously it can't able to handle the torque/load during startup especially heating mode. Check with Carrier Russia.

[Nesey]

Check with Carrier Russia.
This is humor? We have no official representative manufacturers of air conditioners (last - LG - "evacuated" in 2003). The documents on my split - rather than the address of service center of some poultry farms per 100 km.
Thanks, at least there is air conditioning (except China) and the Internet ...

[Nesey]

Incoming power supply voltage any abnormality found?
Thank you! Check it out.

Or outdoor fan and compressor are dying?
It is hardly. Just started.

[Nesey]

I am most worried about a strong hiss at the start of the outdoor unit. Especially at night.

[Nesey]

Carrier start-up program may have some bugs. Obviously it can't able to handle the torque/load during startup especially heating mode.
I think that this is not an error, but rather the characteristics of this particular model. This refers to the speed dial fan speed, and work to the limit. Perhaps this can be attributed to the merits of the model. And if enough soundproof outer box (a thicker layer of rubber), it can even be proud of him.
That is, it helps to achieve maximum results in a shorter time.

[Yuri B.]

Hello
Just a conjecture: possibly the A/C is thus recovering oil from the system - several times a night/day. Doing this after inverter has went for a long while on small rotation, because the load was small, thus, the system being oversized ?

[Nesey]

the system being oversized
Sorry! Say it in another way.

[Yuri B.]

I am not sure whether inverter splits do oil recovery.
What frequencies (compressor speed) does it show on start and, during work ?
Were its installers qualified ?

[Nesey]

What frequencies (compressor speed) does it show on start and, during work ?
After the first run the fan speed is normal. That is an external unit is relatively quiet.
All of the above events occur after 1.5-2 hours and then repeated on a regular basis.
P.S. If it helps: Mode: Heat, Medium, t (on the remote) 24, t (outdoors) +10.

[Nesey]

Were its installers qualified?
This is humor? I live in Russia.

[Nesey]

Were its installers qualified?
Split I installed myself. Local "artisans" to my technique I will not tolerate.:mad::p

[Nesey]

There is another opinion:

This defrost cycle, everything is fine. When working in heat, external works as an evaporator and means that at low temperatures on the street will be covered with frost, and this needs defrosting.
Hiss - Switch 4-way valve.
Wild fan speed - when the cold outside air is still warmer than the heat exchanger, and the machine selects the heat from the air. When working in heat so the fan can spin all the time.

[Yuri B.]

What outside temperatures at nights are?

[Nesey]

What outside temperatures at nights are?
Mode: Heat, Medium. t (on the remote) = +24, t (outdoors) = +10.

[Yuri B.]

Split I installed myself. Local "artisans" to my technique I will not tolerate

But did you vacuumed the system ?!

[Nesey]

But did you vacuumed the system ?!
Yes, I did.

[lexmark42]

What I haven't understood so far is whether the unit actually ran on (possibly low) compressor speed between those cycles.
Also, when the hiss occurs, does the unit already run the compressor or is this just at the beginning of a heating cycle.
This would help differentiate between defrost cycle and "normal" starting, where a noisy expansion valve might cause the hiss (albeit improbable).

Cheers,
-Dave

[Nesey]

What I haven't understood so far is whether the unit actually ran on (possibly low) compressor speed between those cycles.
Outdoor unit fan is - not to move. On the indoor unit - it does not turn off and keep driving the warm air.

[Nesey]

Also, when the hiss occurs, does the unit already run the compressor or is this just at the beginning of a heating cycle.
Hiss loud (enough to wake up at night), not very long (3-5 seconds), at the beginning of each cycle, starting with the second (That is the first time the hiss does not.).

[paul_h]

If it happens every 1.5hr or so, then it is normal defrost. Cold liquid refrigerant to the indoor, then switches back to hot gas. That explains the noise and the short period of cool air on fan restart.

How long is the pipework between the indoor and outdoor? Is the outdoor unit in free room so not recycling it's own cold air? Is the indoor unit free in the centre of the room not to close to corners or ceiling?

For example, an indoor unit near the corner of a room, or too near the ceiling, or with the outdoor unit directly behind with 30cm piping, will alway defrost even at 10C and will often make loud noises when doing so.
Welcome to Australian where that is common. :( It is humour here that installers do that, because they know no better.
But let us know the install setup if it's different.

[lexmark42]

Hi Paul,

I agree on the defrost - this seems most likely from what we have collected so far.

But I fail to understand why short pipe length make the unit prone to frequent defrosting. Could you please enlighten me?

On the other hand, what about slight refrigerant shortage as a possiblity, leading to too low evaporation temperatures?

Cheers,
-Dave

[Nesey]

...Cold liquid refrigerant to the indoor, then switches back to hot gas. That explains the noise and the short period of cool air on fan restart.
Thank you! I also thought about this variant as the most likely (but kept quiet out of modesty:cool:).

How long is the pipework between the indoor and outdoor?
4 m

Is the outdoor unit in free room so not recycling it's own cold air?
Perhaps this is part of the problem. External power is on the balcony and the air outlet was not enough. And maybe because of that frostbite was more intense. Already remade.

an indoor unit near the corner of a room or too near the ceiling...
70 cm from the corner, 15 cm from the ceiling.

or with the outdoor unit directly behind with 30cm piping

This category of tales installers of air conditioners.:D

Welcome to Australian where that is common.
This type of setup is typical for small houses, huts, if this factor is met with meeting these houses hurry economical inexperienced installers. Maybe in Australia, too ...

[paul_h]

Hi Paul,

I agree on the defrost - this seems most likely from what we have collected so far.

But I fail to understand why short pipe length make the unit prone to frequent defrosting. Could you please enlighten me?

On the other hand, what about slight refrigerant shortage as a possiblity, leading to too low evaporation temperatures?

Cheers,
-Dave
Indoor pipe temp will be warmer as system is overcharged with short piping. High indoor pipe temp stops or slows down outdoor fan to bring indoor coil temp down. That makes the outdoor unit ice up more.

The noisy defrost and the fact it was defrosting at 10C outdoor temp made short piping the most likely thing.

[Nesey]

system is overcharged with short piping
Factory refill ***** - up to 5 m line (if not specified, whichever is greater). The instructions (sometimes) clarify - at least 3 m. In other words, the excess refrigerant, can fit in 2 m of line they consider acceptable, and more - overcharged.

[Nesey]

system is overcharged with short piping.
By the way, in line 3 m (1 / 4) contains about 100 g of ***** (not counting my).

[paul_h]

Piping lengths of more than 2m between units normally don't have this noise and too frequent defrost problem, I was just answering lexmark42s question.

If you have a 3m pipe length between the units, then you are not going to have high indoor coil temps causing this problem or have the noisy defrost that happens with too short a pipe length. It was just my theory that would be the cause before I knew you had 3-4m of pipework.

Defrosting at 10C ambient is a little bit strange, maybe it's colder than that outside though, or the airflow around the outdoor unit is not very good.

Besides that though, you just have a unit that defrosts noisily, some models do even when pipe work and refrig charge OK.
What's the carrier inverter manufacturer? Toshiba or chinese cheap brand rebadged?

[lexmark42]

Thanks Paul, interesting to learn about the short pipe length problem; in the end, so many things are a control problem after all :)

@Nesey: Could you manage to have a look at the outdoor unit when it starts the hissing? If you are very quick to look, maybe you can find a bit of ice on it after all. Also you could check how the temperature on the condenser changes.

[Nesey]

What's the carrier inverter manufacturer? Toshiba or chinese cheap brand rebadged?
Made in China. As for "brand rebadged" - not sure.

[paul_h]

Thanks Paul, interesting to learn about the short pipe length problem; in the end, so many things are a control problem after all
Not really a control problem but a fact of life when selling precharged splits. Manufacturer can only do so much and have no control over the install. Not enough refrigerant, or no refrigerant, too many people unqualified or unable to buy refrigerant can't install them, and Gary would hate it if they weren't precharged with an estimated amount of refrigerant.

It's an impossible situation to know how much to pre-charge a system, but , meh, it's the world we live in.
Australia is all back to backs with short pipe runs and overcharged. Asia is probably all apartments and multi level housing and probably 10m runs and undercharged...
Can't win.


Made in China. As for "brand rebadged" - not sure.
Well Made in China isn't a problem, as long as it was designed properly somewhere else.

Rebadged and designed in china...Never come across a quiet unit. They promise to heat and cool, and do that, but are never quiet.

[lexmark42]

Nah I mean control problem as in feedback control. Or is it really just the overcharging?

I would expect that with short pipe runs the condenser temperature rises more quickly, requiring different control parameters in the indoor controller unit.

Otherwise, a decent accumulator should also do the job, shouldn't it?

[paul_h]

We're talking heating cycle here, where compressor discharge goes to indoor coil, obviously the indoor coil smaller than 'condenser' or outdoor unit, and it's charged to cool effectively in cooling mode.
So in heat mode, it's an under sized condenser, placed up high in the warmest area... It's going to overheat, and the common way to prevent that is slow/stop the outdoor fan ~ 55C (which causes outdoor unit to ice up and need regular defrosting). Short pipe runs seem to cause higher temps in the first place for the indoor.
It's not really a control thing, but a design thing, with small indoor units and a charge big enough for effective cooling in summer with possible long pipe runs required by *some* installers.

[Nesey]

I redid the design.
1. Air Conditioning fenced barrier on the main balcony and more opened it to the street. Formerly part of the exhaust air from falling on him.
2. Planted under the base frame is another layer of polypropylene (three). By the way dampens vibrations well polypropylene.
3. Long evacuated outer block, then tucked it with *****.
As a result,
1. Hiss disappeared. Now I do not jump at night.
2. External power became quieter. This is understandable - he of the partition plus insulating layer.
True, there were differences. Cycles have become smaller and louder became the buzz compressor (but not so much that it bothered).

[lexmark42]

Did you put in a different (smaller) charge than before?

@Paul: Sure, I absolutely agree. Undersized indoor units are big trouble and also spoil efficiency in heating. I found that the Mitsu Hyper Inverter units can apparently vary the capacity of the indoor coil by means of a solenoid valve in the indoor unit.

Cheers,
-Dave.

[Nesey]

Did you put in a different (smaller) charge than before?
Perhaps, this time a little more.