how do I find the right HVAC repair person?

[paul42]

I have a Fujitsu 18RLQ mini-split with a strange problem. The good news is that it is still under warranty.

It cools just fine - as long as you want 72 degrees. We want 68. It appears that no matter where I set the thermostat, it cools the bedroom down to 72 degrees and starts cycling on and off. No error codes show up on the wired remote. It seems likely that the problem is in the electronics.

The original contractor has one installer with experience - i.e. ours was the second mini-split he has installed.

The Fujitsu web site lists contractors, but doesn't claim that any of them have any training or any reason other than they are on the web site and close to call them. The last time I tried calling somebody from this list, I kept hearing that they no longer worked on Fujitsu.

So, how do I find somebody that has actually seen a Fujitsu mini-split before?

[referrob]

Call your local contractors and ask if the sell and service Fujitsu, and if their techs are factory trained.

[paul42]

The Fujitsu web site does not list any contractors with factory training within 100 miles of my location.

Their are approximately 120 HVAC contractors within 25 miles of my address. Which one should I start with?

The Fujitsu warranty covers the parts, it does not cover the labor.

It is not hard to find a contractor that can install the typical split system and make it work. Based on my experience so far, finding one that knows anything about mini-splits or electronic controls is another matter all together.

If the problem was a leak and low on freon, then I would just call the original installer. However, it is fairly obvious that this problem has nothing to do with the sealed system, it is a problem with the electronic controls.

I am quite willing to pay a knowledgeable technician to come out, see what the problem is, order the part, and replace it.

However, I really do not want to pay big service fees to some technician that has never seen a mini-split before. I would be better off fixing it myself and paying for the part.

I am an electrical engineer and have been troubleshooting electronics since about 1970. I understand electrical code, and have a copy of the applicable code book. I have worked on commercial refrigeration systems, elevators, x-ray machines, TV's, etc. I design, build, and troubleshoot very high performance computer systems for a living. If I'm going to hire somebody to fix a problem, they had better bring some experience to the job that I don't already have.

How do I find that person?

[WhoIsThat?]

within 100 miles of my location.

120 HVAC contractors within 25 miles of my address. Which one should I start with?

finding one that knows anything about mini-splits or electronic controls is another matter all together.

it is fairly obvious that this problem has nothing to do with the sealed system, it is a problem with the electronic controls.
I wouldn't tell them that.

do not want to pay big service fees to some technician that has never seen a mini-split before.

I am an electrical engineer
Don't tell that either.


This was my advice to my once girlfriend, whose car problem baffled me [and this method worked but she married someone else, anyway].
Ask to speak to the best diagnostician each of your candidate companies has and tell him/her your symptoms and give that person one or two guesses as to what make and model you have.

Make it clear that your reasons for this challenge is that you, and no reasonable person, wants to enter the Slippery Slope known as "troubleshooting by parts replacement" and "throwing good money after bad."

[paul42]

A very reasonable approach.

It usually doesn't take very long for people to figure out that I'm an engineer though.

Before I start calling HVAC shops, I think I will give Fujitsu a call and see what they can tell me.

[WhoIsThat?]

It usually doesn't take very long for people to figure out that I'm an engineer though.

Have you figured out that I am one? :p

[freefall]

It usually doesn't take very long for people to figure out that I'm an engineer though.




You say that like its a good thing. :rolleyes:

You are the customer most hvac techs hate to help. ..... an engineer, or even worse, a retired one that is board.

To get good service, keep your nose out of things, leave the tech alone, let him/her do their job.

You do not know more than them, you do not have the resources the tech has.

Follow these rules and you'll get fixed up...

[john_ertw]

To get good service, keep your nose out of things, leave the tech alone, let him/her do their job.

You do not know more than them, you do not have the resources the tech has.

Follow these rules and you'll get fixed up...

In the ideal world this would be the case every time, but in the real world it depends on the tech that comes out. Otherwise there would be no reason for homeowners to come to this board. There would also be no reason for techs either since they would all know everything there is to do with HVAC.

[Some Dude]

You say that like its a good thing. :rolleyes:

You are the customer most hvac techs hate to help. ..... an engineer, or even worse, a retired one that is board.

To get good service, keep your nose out of things, leave the tech alone, let him/her do their job.

You do not know more than them, you do not have the resources the tech has.

Follow these rules and you'll get fixed up...

Couldnt agree more, i actually charge more.

Unless you have a keen grasp of the complete refrigeration cycle and everything in between most of us do more walking up to a unit than we could ever explain. The way it sounds, the way its installed, and on and on and on.
Taken Separately this isnt rocket science, but everything working together is a different story.
So far it doesnt sound like you need us anyway, and since we cant really answer any technical questions theres that to consider as well.

[freefall]

In the ideal world this would be the case every time, but in the real world it depends on the tech that comes out. Otherwise there would be no reason for homeowners to come to this board. There would also be no reason for techs either since they would all know everything there is to do with HVAC.


I never stated that any tech knew everything. I just stated that an hvac tech will know more and have more resources than joe-homeowner.

[paul42]

You say that like its a good thing. :rolleyes:

You are the customer most hvac techs hate to help. ..... an engineer, or even worse, a retired one that is board.

To get good service, keep your nose out of things, leave the tech alone, let him/her do their job.

You do not know more than them, you do not have the resources the tech has.

Follow these rules and you'll get fixed up...

I've tried that in the past and it didn't work.

My last experience was when I hired an hvac company to install a Honeywell IAQ thermostat on my Trane heat pump. When I talked to the people on the phone, they assured me that they knew exactly what I was asking for and it would be no problem.

The tech came out, took my thermostat off the wall, and started to install a different one - not a Honeywell IAQ, not even close. The tech assured me that the Honeywell IAQ would not work with my system. I told him to put the original thermostat back on, and I paid the service fee.

I ordered the Honeywell IAQ from an online source and installed it myself, not particularly difficult. Somebody with experience could have done it a lot faster, but it would have taken longer for me to find somebody with experience than it did to install it myself.

So much for "keeping my nose out of it and getting good service". In the real world, it doesn't always work that way.

This time, I'm trying to find a tech that actually does know more than I do.

I don't care if I do get charged more because I'm an engineer as long as I'm satisfied that the tech brings real experience and knowledge to the task, and isn't just another part swapper. I'm not looking for the cheapest price, I'm looking for somebody that has experience and real knowledge with mini-splits and electronic controls.

[HVAC9900]

Am not very familiar with the wall hung stuff, but would check the settings on the remote(assuming there is one) maybe there some kind of "economy cooling/energy saving" setting on this thing?
Or possibly the differential temp setting needs to be changed. If that doesn't do it, then you probably need a tech.

I have no problem believing the story about the tech with the stat.On the rare occasions I have to have one of my vehicles serviced by someone other than myself, it's a huge roll of the dice that the company knows what they are doing, as well as the tech who does the work.

Had one my vehicles back to the dealer for a call back(in our trade thats when you probably didn't fix the problem the last time you were there and the customer called back),figured the dealer would do the best job.Sometimes they do.

[paul42]

I am an engineer, and I am quite proud of it. I do not know everything, but I know from experience that if I want things done right, then I'd better be there to make sure it happens.

My wife and I were the contractor for our new house - finished about 16 months ago. My wife can tell you about all the many things I caught during construction. I bought and read the applicable code books and I understood why the code was written the way it was. There are some things I still disagree with - such as arc fault interrupters, but I understood the code. On the sections that applied to my house, I knew more than the licensed plumbers and electricians.

I'm also a reasonable person. If the sub contractor gave me a good reason why it should be done that way, and if the independent inspector I hired agreed with them, then I was all for it. The independent inspector I hired was state licensed, an ex contractor, and an ex air force pilot. Hiring him was one of the smartest things I did.

[paul42]

Am not very familiar with the wall hung stuff, but would check the settings on the remote(assuming there is one) maybe there some kind of "economy cooling/energy saving" setting on this thing?
Or possibly the differential temp setting needs to be changed. If that doesn't do it, then you probably need a tech.

I have no problem believing the story about the tech with the stat.On the rare occasions I have to have one of my vehicles serviced by someone other than myself, it's a huge roll of the dice that the company knows what they are doing, as well as the tech who does the work.

Had one my vehicles back to the dealer for a call back(in our trade thats when you probably didn't fix the problem the last time you were there and the customer called back),figured the dealer would do the best job.Sometimes they do.

I understand what you are saying about vehicles. I will never, ever, buy another Plymouth.

The wall mounted remote is not the typical thermostat. For mini-split applications, the temperature sensor is not in the remote, it is in the inside unit. The remote has a three wire communication with the indoor unit to set fan speed, temperature, mode, etc.

The wall mounted remote is used for other Fujitsu units. It has an energy saver function, but it is not applicable to mini-splits and is supposed to be locked out. The energy saver function is also supposed to make at most a 4 degree difference. Right now, the wired remote is set to 64 degrees and it is 72.0 degrees in the bedroom with the outside unit cycling on and off. Changing the set temperature to 70 degrees gives me the same 72 degrees result.

It does not have a way to change the temperature differential.

[Shophound]

I would call or email Fujitsu, give them your system's model number, and ask them point blank if it is by design the system will not allow itself to cool a room below 72 degrees.

Does the blower on this minisplit run constantly when the outdoor section cycles off? While it has a smaller coil, it will still evaporate moisture off that coil when the compressor cycles off. You may be making that room less comfortable via the blower running constantly, thereby causing you to wish you could set the unit colder. I think we had a similar discussion concerning your central a/c, whereby you found out that when you set the indoor blower to "auto", your indoor humidity levels dropped. Could be a repeat scenario with your minisplit, if the blower always runs.

[Carnak]

I am an engineer, and I am quite proud of it. I do not know everything, but I know from experience that if I want things done right, then I'd better be there to make sure it happens.

My wife and I were the contractor for our new house - finished about 16 months ago. My wife can tell you about all the many things I caught during construction. I bought and read the applicable code books and I understood why the code was written the way it was. There are some things I still disagree with - such as arc fault interrupters, but I understood the code. On the sections that applied to my house, I knew more than the licensed plumbers and electricians.

I'm also a reasonable person. If the sub contractor gave me a good reason why it should be done that way, and if the independent inspector I hired agreed with them, then I was all for it. The independent inspector I hired was state licensed, an ex contractor, and an ex air force pilot. Hiring him was one of the smartest things I did.you are an electrical engineer, out of your realm of expertise and are on an hvac forum asking for help.

You are starting to sound like the classic strereotype of an engineer that gives the guys here a chip on their shoulders. Your type gives all engineers a bad name with tradesmen.

If that fujitsu is a heat pump most likely it is auto-change over. Read your manual on what it says about set points. The heating and cooling set points are dependent on one another if it is auto change over, maybe heating is set higher than 68F

Your humidity problem last year was user error, I suspect this problem is the same

[Some Dude]

you are an electrical engineer, out of your realm of expertise and are on an hvac forum asking for help.

You are starting to sound like the classic strereotype of an engineer that gives the guys here a chip on their shoulders. Your type gives all engineers a bad name with tradesmen.

If that fujitsu is a heat pump most likely it is auto-change over. Read your manual on what it says about set points. The heating and cooling set points are dependent on one another if it is auto change over, maybe heating is set higher than 68F

Your humidity problem last year was user error, I suspect this problem is the same

Engineers , the smartest guys they know:D

[Carnak]

Engineers , the smartest guys they know:D

I know one like that

[Some Dude]

I know one like that

Just one:D

[paul42]

I would call or email Fujitsu, give them your system's model number, and ask them point blank if it is by design the system will not allow itself to cool a room below 72 degrees.

Does the blower on this minisplit run constantly when the outdoor section cycles off? While it has a smaller coil, it will still evaporate moisture off that coil when the compressor cycles off. You may be making that room less comfortable via the blower running constantly, thereby causing you to wish you could set the unit colder. I think we had a similar discussion concerning your central a/c, whereby you found out that when you set the indoor blower to "auto", your indoor humidity levels dropped. Could be a repeat scenario with your minisplit, if the blower always runs.

I am out of my realm of expertise. However, the only help I'm looking for on this forum is how to find a technician that has expertise in mini-splits and electronic controls. Fixing the mini-split will almost certainly involve swapping out the correct circuit card from the indoor unit.

In the past, the mini-split has cooled the room down to 68 degrees with no problem. The current misbehavior is new. I think that rules out a design issue.

The blower on the minisplit does run constantly (speed varies, but never goes completely off), there does not appear to be any way to defeat that. However, this is an inverter driven system, so if the thermostat is set at 68 degrees, this time of the year, the outside unit almost never shuts off completely. It just ramps down to a very low speed.

The dew point in my house is running a little under 50 degrees with the current set up.

The mini-split does allow auto operation, ie switching betweeh heating and cooling. However, I NEVER use that mode. I always set it to either heat or cooling modes.

From real world experience, the only tradesmen that have problems working with me are the ones that do not know what they are doing, but think they know it all.

I had very good working relationships with most of the subcontractors on my house, including the HVAC installers. I am an electrical engineer, who also has real world experience with refrigeration systems, plumbing, carpentry, auto repair, electrical wiring, etc... In the past, I earned my living doing all of the above (except the auto repair).

I do not presume to know it all, otherwise, I would not be on this board trying to find a knowledgable technician. When I was building the house, I paid extra for subcontractors that knew what they were doing. I paid extra to have an outside licensed inspector to act as my "on call" expert.

I think that results speak for themselves. I designed and built a 4,000 sq. ft. house that I can cool to 74 degrees when it is 103 outside with a 2 ton heat pump (the mini-split is only on at night). All of this was done using typical frame construction. This was also the first house that I have ever built. I am not your typical homeowner, nor am I your typical engineer. Stereotyping engineers is no better than lumping all hvac techicians in the same category.

[Carnak]

4000 square feet which includes a basement, basement gets cooled by the earth, a heat pump water heater and your main system and you use a mini-split as well, so it is not 2000 sq feet per ton like you brag about all the time.

So it sounds like you are trying to convince a woman that 4 inches is 7

You are fitting the stereotype quite well you cannot help but have to state that you are an engineer and you give the rest of the profession a bad name by your actions. You are the classic, an electrical engineer trying to argue air conditioning

Same smug attitude as last summer, that had a hard time accepting that your own behaiviour and way of operating the system was what was driving up your own humidity levels.

Most likely someone messed with the heating setpoint. Occupant error just like last summer

[HVACJOEK]

A very reasonable approach.

It usually doesn't take very long for people to figure out that I'm an engineer though.

Before I start calling HVAC shops, I think I will give Fujitsu a call and see what they can tell me.

Do you know who was the most famous engineer?:cool:

[Some Dude]

4000 square feet which includes a basement, basement gets cooled by the earth, a heat pump water heater and your main system and you use a mini-split as well, so it is not 2000 sq feet per ton like you brag about all the time.

So it sounds like you are trying to convince a woman that 4 inches is 7

You are fitting the stereotype quite well you cannot help but have to state that you are an engineer and you give the rest of the profession a bad name by your actions. You are the classic, an electrical engineer trying to argue air conditioning

Same smug attitude as last summer, that had a hard time accepting that your own behaiviour and way of operating the system was what was driving up your own humidity levels.

Most likely someone messed with the heating setpoint. Occupant error just like last summer

But man he sure can give out some advise, check out his posts. This guy needs a hobby, hopefully non hvac related

[jrbenny]

If you don't like the topic, move along.


No need for bashing members regardless of your disdain for their profession or personality.

[paul42]

When I say I am conditioning 4,000 sq. ft. that is 4,000 sq. ft. above ground.

My house, including the "basement" is 100% above ground. From the tax collector's point of view, I have an unfinished, ie nontaxable, basement. From a construction point of view, I have a one story pier and beam house with an enclosed crawl space.

The house is supported above the foundation and crawl space using 2x6 framed cripple walls. I hired the framer that understood what I was talking about, not the lowest bid.

The house and the crawl space are each 2,230 sq. ft. Approx 1,800 sq. ft. of the crawl space has a concrete floor and 10 to 6 foot ceiling height. The concrete floor is stepped to follow the original terrain The remainder of the crawl space is a vapor barrior covered dirt bank with decreasing head room - but is still quite useful for storage. All of our Christmas stuff, etc... is in plastic tubs laying on the vapor barrier.

So, when I say I am conditioning 4,000 sq. ft. that is 4,000 sq. ft. above ground and does not include the dirt floor storage area.

The basement is running a constant 71 degrees in the summer. To hit 71 degree soil temperature in our part of the country would require going down about 8 feet. When drilling the foundation piers, we hit rock before we hit 8 feet. No significant earth cooling involved.


The "basement" is cooled partially by the heat pump water heater - just one of many design decisions that means I cool 4,000 sq. ft. with a 2 ton heat pump. While running, it provides about 4,000 btu of cooling and dehumidfication. It heats the water for about 40% the cost of straight resistance heat. Sounds like a good engineering decision to me.

The mini-split is turned off during the day and is not needed to keep the house at 74 degrees when it is 103 outside.

Smug attitude or not, my results still speak for themselves.

There are seperate temperature settings for heat, cool, and auto. All are set to 64 degrees.

[paul42]

Do you know who was the most famous engineer?:cool:

The engineering answer is
Scott Adams - cartoonist and creator of "Dilbert" :)

[HVACJOEK]

The engineering answer is
Scott Adams - cartoonist and creator of "Dilbert" :)


A nice attemp, but no cigar Scott Adams recieved his degree in Economics. I was hoping that the most famous engineer would not be forgotten so soon.
after all he brought joy to many childrens faces,he even had a famous jingle associated to him.:cool:

[Shophound]

Paul, when you run the minisplit at night in your bedroom, what does the whole house system do? Go into setback mode or continue running normally?

72 degrees at ~50°F dewpoint is around 46% relative humidity. Personally, I would find such conditions almost chilly in my own home after some time at rest (and my wife would be dressed like an eskimo). Not everyone has the same comfort levels, however. I only mention this because temperature isn't the only thing to look at. Several other items factor into human comfort within a room, as appears every time I post in my signature.

So, you can either try to somehow coax the minisplit to go lower (temperature), get it drier in the room (humidity), increase air movement (install a ceiling fan over the bed), or see if the sun is beating the crap out of one of your bedroom walls, leading to heat migration into the dwelling, even after the sun has set (mean radiant temperature). Insulation does not stop the transfer of heat, only slows it. After sunset the exterior surface of the wall is still warmer (as is the air) than the interior drywall surfaces exposed to the room, so the heat migration will follow the second law of thermodynamics precisely.

[paul42]

Paul, when you run the minisplit at night in your bedroom, what does the whole house system do? Go into setback mode or continue running normally?

72 degrees at ~50°F dewpoint is around 46% relative humidity. Personally, I would find such conditions almost chilly in my own home after some time at rest (and my wife would be dressed like an eskimo). Not everyone has the same comfort levels, however. I only mention this because temperature isn't the only thing to look at. Several other items factor into human comfort within a room, as appears every time I post in my signature.

So, you can either try to somehow coax the minisplit to go lower (temperature), get it drier in the room (humidity), increase air movement (install a ceiling fan over the bed), or see if the sun is beating the crap out of one of your bedroom walls, leading to heat migration into the dwelling, even after the sun has set (mean radiant temperature). Insulation does not stop the transfer of heat, only slows it. After sunset the exterior surface of the wall is still warmer (as is the air) than the interior drywall surfaces exposed to the room, so the heat migration will follow the second law of thermodynamics precisely.

At night, the whole house system continues to run normally with its thermostat set at 74 degrees.

During the daytime, 74 degrees and 40% relative humidity is about right for us. At night, we like it cooler than that. The minisplit doesn't dehumidify very well (very disappointed in that), so the dew point stays about the same.

I really expected an inverter driven variable speed system to provide much better dehumidification than I got. Even when it was set to a temperature that forced the compressor to run constantly, it did not dehumidify very well at all.

Up until about a month ago, the minisplit did a good job of cooling the bedroom down to 68 degrees.

I have called and emailed Fujitsu. The lady I talked to on the phone agreed that their web site did not show any trained techs in my area (DFW Texas). She "claims" that they will find somebody qualified to work on my system. I'm waiting for a call and or email back. Hopefully that will happen in the next day or so. Previous emails have been ignored, maybe this one will be different.

[HVACJOEK]

Not to insult your intelligence,but you did read the manual? Assuming that you have the wireless remote control,are you hearing the beep when trying to set the temperture? If not look for a small hole (reset button) on the remote depress it to reset the remote back to the default settings,then reprogram. 7 out of 10 times this is the problem.:cool:
ps super quiet mode limits compressor output

[Shophound]

At night, the whole house system continues to run normally with its thermostat set at 74 degrees.

During the daytime, 74 degrees and 40% relative humidity is about right for us. At night, we like it cooler than that. The minisplit doesn't dehumidify very well (very disappointed in that), so the dew point stays about the same.

I really expected an inverter driven variable speed system to provide much better dehumidification than I got. Even when it was set to a temperature that forced the compressor to run constantly, it did not dehumidify very well at all.

Up until about a month ago, the minisplit did a good job of cooling the bedroom down to 68 degrees.

I have called and emailed Fujitsu. The lady I talked to on the phone agreed that their web site did not show any trained techs in my area (DFW Texas). She "claims" that they will find somebody qualified to work on my system. I'm waiting for a call and or email back. Hopefully that will happen in the next day or so. Previous emails have been ignored, maybe this one will be different.

Up until a month ago, we had not yet experienced a long string of 100+ degree temperature days. During our recent "cool spell" (that is, until Saturday) and now that cooler, humid weather has returned again, can the minisplit achieve < 72 degrees?

Has the minisplit been serviced since new (outdoor coil cleaned, indoor filter changed, etc.)?

It's possible the system may have a small refrigerant leak, resulting in loss of capacity. Why it shuts off at 72 vs. 68...the outdoor unit may have a low pressure safety device installed. There may not be a control problem at all.

Have you ever measured the discharge air temperature of this minisplit over a wide range of operating conditions?

[paul42]

Not to insult your intelligence,but you did read the manual? Assuming that you have the wireless remote control,are you hearing the beep when trying to set the temperture? If not look for a small hole (reset button) on the remote depress it to reset the remote back to the default settings,then reprogram. 7 out of 10 times this is the problem.:cool:
ps super quiet mode limits compressor output

I'm open to any and all suggestions.

However, I do not have the wireless remote. I have the wired remote. I have read and reread the manual for the wired remote several times. I've experimented with just about every setting it will let me access. I've totally powered down the whole system for hours. I've hit the reset switch on the wall unit.

[HVACJOEK]

E-mail me if you need the service instructions.:cool:

[paul42]

Up until a month ago, we had not yet experienced a long string of 100+ degree temperature days. During our recent "cool spell" (that is, until Saturday) and now that cooler, humid weather has returned again, can the minisplit achieve < 72 degrees?

Has the minisplit been serviced since new (outdoor coil cleaned, indoor filter changed, etc.)?

It's possible the system may have a small refrigerant leak, resulting in loss of capacity. Why it shuts off at 72 vs. 68...the outdoor unit may have a low pressure safety device installed. There may not be a control problem at all.

Have you ever measured the discharge air temperature of this minisplit over a wide range of operating conditions?

No, the unit still will not go below ~ 72 degrees. From all appearances, it does not even try. When I turn the unit on in the evening, with the fan set to auto, the unit will slowly ramp up to a high blower speed. As the bedroom temperature approaches 72 degrees, the blower speed ramps back down. This takes about 30 minutes During the night, it occasionaly ramps the speed back up for a few minutes, and then back down again to maintain the temperature at 72 degrees.

The minisplit has not been serviced since new. However, the outside unit at least looks clean, and I have cleaned the indoor filters several times. I have never seen more than a trace of dust on the indoor filters (they are not the replaceable style).

I have measured the discharge air temperature while the blower was running in high speed and it was approximately 55 degrees.

I cannot say for certain that it does not have a refigerant leak. However, it has numerous error codes that it can display and I would be very surprised if a pressure safety switch would not trigger one of those codes. The quick pull down implies to me that it is not a cooling capacity issue.

At 18,000 btu, the minisplit is very oversized for our bedroom. I asked for the 12,000 btu model. However the contractor was not willing to put the smaller one in a North Texas house that only had a 2 ton heat pump. So, I compromised and let them bid and install the 18RLQ instead. My bad.

[HVACJOEK]

No, the unit still will not go below ~ 72 degrees. From all appearances, it does not even try. When I turn the unit on in the evening, with the fan set to auto, the unit will slowly ramp up to a high blower speed. As the bedroom temperature approaches 72 degrees, the blower speed ramps back down. This takes about 30 minutes During the night, it occasionaly ramps the speed back up for a few minutes, and then back down again to maintain the temperature at 72 degrees.

The minisplit has not been serviced since new. However, the outside unit at least looks clean, and I have cleaned the indoor filters several times. I have never seen more than a trace of dust on the indoor filters (they are not the replaceable style).

I have measured the discharge air temperature while the blower was running in high speed and it was approximately 55 degrees.

I cannot say for certain that it does not have a refigerant leak. However, it has numerous error codes that it can display and I would be very surprised if a pressure safety switch would not trigger one of those codes. The quick pull down implies to me that it is not a cooling capacity issue.

At 18,000 btu, the minisplit is very oversized for our bedroom. I asked for the 12,000 btu model. However the contractor was not willing to put the smaller one in a North Texas house that only had a 2 ton heat pump. So, I compromised and let them bid and install the 18RLQ instead. My bad.


Which error codes are being diplayed ?? After all is said and done I put my money on a thermister problem, ... you should check that. :cool:

Here is a paragraph from the service manual.

A sensor (room temperature thermistor) built in the indoor unit body will usually perceive
difference or variation between a set temperature and present room temperature, and
controls the operation frequency of the compressor.
* If the room temperature is 4°F(2°C) higher than a set temperature, the compressor operation
frequency will attain to maximum performance.
* If the room temperature is 5°F(2.5°C) lower than a set temperature, the compressor will be
stopped.
* When the room temperature is between +4°F(+2°C) to -5°F(-2.5°C) of the setting temperature,
the compressor frequency is controlled within the range shown in Table1.
However, the maximum frequency is limited in the range shown in Figure 1 based on the
fan speed mode and the outdoor temperature.

[paul42]

E-mail me if you need the service instructions.:cool:

The offer is greatly appreciated, but I downloaded those off the net before the unit was even installed.

Fujitsu_18RLQ_Halcyon_System_Service_Manual.pdf
Fujitsu_18RLQ_Halcyon_System_Technical_Data.pdf

I could run the forced cooling test. That would at least rule out a capacity issue.

I could get ambitious and check the indoor thermistor.

I know how to change the timing belt on my car, but I'm not willing to do it myself. I find somebody that does it all the time and pay them to do it.

I probably could, eventually fix this minisplit myself. But, I would much rather find somebody that has worked on them before and pay them to do it.

[paul42]

Which error codes are being diplayed ??:cool:

no error codes at all.

[Daltex]

If the stat is set to auto then it will just monitor the temp once it gets to within 4* of the setpoint. Lower the setpoint to 66* and see if it shuts down @ 70*. If so then you are confusing the auto fan with the auto Heat/Cool setting.

I'm sure you know this but it's worth a shot if you haven't tried it.

[Carnak]

Not to insult your intelligence,but you did read the manual? Assuming that you have the wireless remote control,are you hearing the beep when trying to set the temperture? If not look for a small hole (reset button) on the remote depress it to reset the remote back to the default settings,then reprogram. 7 out of 10 times this is the problem.:cool:
ps super quiet mode limits compressor output

Is bad batteries in remote the other 3 times out of ten :)

[paul42]

If the stat is set to auto then it will just monitor the temp once it gets to within 4* of the setpoint. Lower the setpoint to 66* and see if it shuts down @ 70*. If so then you are confusing the auto fan with the auto Heat/Cool setting.

I'm sure you know this but it's worth a shot if you haven't tried it.

I currently have the set point at 64. But thanks for the suggestion.

The auto/fan vs auto heat/cool setting are not that easy to confuse on the remote. The display is quite specific for each.

[Daltex]

As I said, I was sure you would know that but missed the current setpoint being at 64*.

So you have the heat/cool on cool and the fan on auto. Setpoint for cool @ 64*. System pulls back @ 72*. Got it.....

Was there any fluctuation in temp over the last few weeks? If it's able to pull it down to 72 with the 100*+ ODT, the unit should have no problem with the milder temps of late. Sounds like a control board issue to my very untrained eyes.

Maybe it's Fujisu's way of lowering the cap and trade pinch.......

[HVACJOEK]

Is bad batteries in remote the other 3 times out of ten :)



No!! Bad batteries is actually 37-41-62 and 93 out of a Hundred.. lol

The other three usally involves the house pet and their need to chew...:cool:

[paul42]

Current outdoor temperature is 78 degrees.
Set point for minisplit is 64.
Actual temperature in bedroom is 71.7

fan set to auto, running on low.

it's either the controller or the thermistor.

Now, if Fujitsu would just call me back or send me an email - otherwise I will have my wife give them call. I'm the easy going one, my wife makes things happen.

[paul42]

Despite what the lady from Fujitsu service told me on the phone, I never heard back from them. I suspect they just didn't have any techs in my area that had any training on their units.

So, I called the company that installed my mini-split to start with. They sent out a new technician, one that has actually worked on mini-splits before.

The guy showed up right on time, listened to what I said was wrong and what I had already tried, did a couple of quick temperature measurements to verify what I told him, went through the service manuals that I had printed out, tested the thermistor (after a lot of grief getting to the pc board), found that it was reading way too low and has ordered a replacement.

This company has always treated me fairly, and they now have some techs with at least a little experience with mini-splits and reasonable trouble shooting skills. So, they will continue to get my business.

Because I had already tried all the easy answers, read the manuals from cover to cover and had them sitting there, completely reset the system, etc... before the tech came out, the call was reasonably quick. The time consuming part was opening up the unit far enough to get to the connection for the thermistor.

[Shophound]

Glad to hear you're receiving a happy resolution to this problem. And good on your contractor for having someone on staff who can work on more complex equipment. Thanks for sharing this positive news. :)