Daikin FTXS71GV1B advice

[TrickyRikki]

Hello all,

its me again with another issue with Daikin, my office is based on a farm and we look after all the refrigeration and air conditioning for the farmer/farm workers as a favour for having our office based on site.

Basically the issue happened 2 weeks ago when the unit was reported as not cooling at all, when i went to have a look i found the condensing unit to have a faulty thermistor loom, i replaced the 3 thermistors and ran it up and kept an eye on it all day while i was working on site with no issues at all.

2 days later the staff had to turn the unit off as apparently it was set to 18 but blowing out hot, today was the first time i managed to get back to checking the unit out and went through the error history but no errors were found on the unit, i checked the wiring, indoor thermistors which were fine, voltages seem fine everywhere, refrigerant pressures were fine, ran the unit up again and the unit bought the room back down to temp and went out on stat multiple times, i had a temp difference of 12C from air on to air off.

In the end i stripped both indoor and outdoor unit down to go over everything with a fine tooth comb to see what the issue is, the 4 port valve seems to work okay, the comp ramps up and down as it should, the fan ramps up and down. everything seems to be doing what it is designed to do.

Am i missing something obvious here? the only other thing i found is the unit is undersized for the area, if i done the maths right the room needs at least a 12kw unit where as this unit is a 7kw unit.

I phoned Daikin who said if it isnt showing an error code and ive tested everything else that i went through with them there isnt alot they can suggest so i thought i would see if anyone on here has any pointers or has come across an issue like this?

[r.bartlett]

someone messing with the controller?

[TrickyRikki]

someone messing with the controller?

Wish it was that simple, the unit is located in a main entrance lobby area, people come in walk past the unit and then upstairs, the IR controller is tucked up out the way to stop people altering the set point ect.

Just dont understand how everything can be pointing to a unit thats working fine all the time im on site but apparently it just blows out hot even tho its set to cool 18.

As i said its on the office grounds so i can keep an eye on it over the next few days but its just stumped me as to how/why its doing it

[seanf]

Had an air to air heat pump that the customer thought was blowing out cold air every so often. People thinking its blowing out hot air, but its just recirculating the air?

[TrickyRikki]

Had an air to air heat pump that the customer thought was blowing out cold air every so often. People thinking its blowing out hot air, but its just recirculating the air?

yeah they have the unit set to 18 to keep the lift lobby area cool, the only thing is the whole front of the building is 1 huge window spanning the width and height of the room. thats what got me thinking about the unit being undersized, a previous contractor installed it and fitted the 7kw unit, but when i worked it out the room requires a 12kw.

every time ive checked the unit and/or maintained it the unit is running fine and blowing out cold, now all of a sudden they are complaining that the unit isnt working in cooling and instead blows out hot, but as i said i spent the day going over everything with a fine tooth comb and everything seems fine

[Brian_UK]

As it's undersized I wonder if it's freezing up and shutting down prematurely. Is the air temperature sensor in a suitable place and selected by the remote rather than using the remote control temperature sensor.

[charlie patt]

I've had this issue many a time occasionally what I've had to do to prove it
What I've done to prove it is to temporary fix a thermometer with the probe on the air outlet and when the draught is felt tell me the temp I've got one at the mo adamant its blowing freezing cold air I've fixed a thermometer to the unit with a k type probe room set to 22 dc auto when they get this horrendous draught I ask what was temp and its varied from 20.9 to 21.1 it's more to do with when the front door is open on this one which means it's just pulsing up first of all you have to prove it is heating or cooling unless u prove it u will get nowhere

[TrickyRikki]

As it's undersized I wonder if it's freezing up and shutting down prematurely. Is the air temperature sensor in a suitable place and selected by the remote rather than using the remote control temperature sensor.

I did wonder the same, but after closely monitoring it for the whole day i didnt notice any signs of the unit freezing up.
The unit in question only has 2 thermistors on it, 1 is mounted to the coil at the back and the other is soldered into the pcb at the front where the IR sensor is, the only sensor it reads from is the ones on the unit and not the remote as i double checked with Daikin about that.

[TrickyRikki]

I've had this issue many a time occasionally what I've had to do to prove it
What I've done to prove it is to temporary fix a thermometer with the probe on the air outlet and when the draught is felt tell me the temp I've got one at the mo adamant its blowing freezing cold air I've fixed a thermometer to the unit with a k type probe room set to 22 dc auto when they get this horrendous draught I ask what was temp and its varied from 20.9 to 21.1 it's more to do with when the front door is open on this one which means it's just pulsing up first of all you have to prove it is heating or cooling unless u prove it u will get nowhere

that would be a good idea if the area in which this unit is installed in had people in it but unfortunately this is literally just an entrance with a stairwell and lift, people sign in at the door and then go upstairs to the office but then someone keeps complaining the unit isnt working, everytime ive worked on it, it has been fine.
Also had a complaint because the condenser was dripping on a car, i have told them not to keep parking under the unit anyway as it makes it alot harder for us to work on the condenser.

Ive not heard anything this week so i assume the office has either shut down due to covid19 or it has been working okay, only time will tell.

[Brian_UK]

Just a thought - am I right in you saying that it is a hand held infrared remote controller not a hard wired one?

1. Is it possible that someone is playing with the controller and then resetting it to cool18' out of range of the indoor unit receiver?

2. Does someone else have a second controller and a grudge?

[seanf]

that would be a good idea if the area in which this unit is installed in had people in it but unfortunately this is literally just an entrance with a stairwell and lift, people sign in at the door and then go upstairs to the office but then someone keeps complaining the unit isnt working, everytime ive worked on it, it has been fine.

Wireless/remote temperature monitor?

[TrickyRikki]

Just a thought - am I right in you saying that it is a hand held infrared remote controller not a hard wired one?

1. Is it possible that someone is playing with the controller and then resetting it to cool18' out of range of the indoor unit receiver?

2. Does someone else have a second controller and a grudge?

I would like to think that someone wouldn't go through the effort of doing that but i cant say 100% that its not happening, everytime i have gone to look at the unit the lady i deal with said she has her suspicions on who keeps complaining about it, and she thinks that they are complaining because they like to park closest to the main entrance which means having the car under the condenser. then they complain that the unit is leaking when the unit drips on the car.

So in all fairness it could be as simple as someone doing that but i would like to think not.

[TrickyRikki]

Wireless/remote temperature monitor?

Could be a possibility, ive never needed to do it before but seeing as this unit seems to be working fine with no issues and they complain it may be the only was to do it.

[Brian_UK]

How about a lock box for the controller?

https://www.fireprotectionshop.co.uk...-sti-9105.html

[TrickyRikki]

How about a lock box for the controller?

https://www.fireprotectionshop.co.uk...-sti-9105.html

That could definitely be an option and solution for it, i will look into it thanks

[B G Scott]

There is now't so strange as folk.
Many, many years ago we installed a/c to a very large open plan office, the system being a large air handler and multi condensing units on a multi sectioned DX coil.
We had endless complains about temperature issues from various parts of the office, the solution we tried and then retained was to provide each area with an adjustable thermostat.
The complaints stopped, but unknown to the office occupants none of the thermostats were connected to the system, what it did do was allow individuals to think they had some control over their local environment.
As I said now't so strange as folk.

[TrickyRikki]

There is now't so strange as folk.
Many, many years ago we installed a/c to a very large open plan office, the system being a large air handler and multi condensing units on a multi sectioned DX coil.
We had endless complains about temperature issues from various parts of the office, the solution we tried and then retained was to provide each area with an adjustable thermostat.
The complaints stopped, but unknown to the office occupants none of the thermostats were connected to the system, what it did do was allow individuals to think they had some control over their local environment.
As I said now't so strange as folk.

LOL that is brilliant, as long as the customer is happy then that's all that matters.

I've not heard any more about this unit since so i assume its either "fixed after my last visit" or the office has been closed for a while due to Covid-19, i cant tell as im currently working on other sites and dont get the chance to often get to the office.