Mr slim temp gauge difference WEIRD

[bcullen]

i put this post in refrigeration DUH

Hi
I have had numerous problems with this model.. I now have one final hurdel.

Inside unit of the PUH-5 at probe reads 22c and at the wall control reads 16c. This causes confusion with the outside units fans. There are no error messages I have bridged the outside fans so they run fast and i can manually warm the area and monitor the room temp physicaly. Eg set temp 28c wall mount reads up to 19c (nice and warm)i then bring the set temp down to 19c and it settles down The problem seems to be with the inside unit, Can you help
"Strange days indeed"
Bryan

[install monkey]

why have u linked out the outdoor fans ur unit is sensing return air temp,u need to enter the setting mode 02 and set for sensing at controller.u state there is no fault codes so clean the filter and dont maul if it aint broken

[stufus]

What's the full model number ?
There is a 3c temperature shift option for return sensor usually used in applications with high ceilings.
If this has been enabled you will see an instant 3c gain on controller when switching between heating and cooling.
If you have the full model number i should be able to point you in the right direction.
Cheers
Stu

[bcullen]

Thanks for replys Ist. Mr install. Fans would turn over slowly STAND BY was permanetly on at the inside control box the result was, no heat Brrrrr. We checked outside using the sw2 method and all was clear We (owner and the fridgy) checked inside unit and with a set of 28c (wall control) and a check read at the inside unit probe 0f 20< the wall control unit would not read over 16c Consequently nothing was happening so We bridged #22 to get fans up to speed when 16c went to 19c on wall unit we changed set28c on same unit to set20c and thing were managable apart from defrost. Ok!! The fillters are new. So we believe there is a problem with how the inside unit reads the probe at the internal unit and hopefully someone can help.
Again thanks also Stufus i hope the above gives a better idea of the problem. I understand the 3c bit but not how it works The unit is a Mod puh-5,6yk,6yk2 hope this helps I should ad that the pipes are new the compressor is new If we can fix this problem i have a very good unit.Bryan

[install monkey]

unit shows standby in heating mode until the coil sensor on the indoor unit reaches approx 32deg then the indoor fan speeds up to reject heat-this is to prevent cold draughts. if a system isnt reaching an indoor coil temp of 33deg then the chances are its short of gas.the mitsi fault codes for a mr slim will only alarm on hi pressure,and compressor overheat.-what are ur standing pressures,running pressures,compressor running current,temp diff accross coils.
when system is in heat mode press the test button twice and unit displays test and then the return air value displays the coil temp ,then do the same in cooling mode .ps take out the links

[bcullen]

Thanks install Removed link fired up Set temp 28c. Wall Reading 14c Test run showed:
heat. auto stop 2hr 5>4 test run
cool. auto stop 2hr 4<5<6 test run
All gauges, flows and refrigerant is as should be
On startup heat at outlets 24c reading at wall unit 14c went into standby 1/2 hr later still in standby
Hope you can help Bryan
Ok another 30 min gone out of standby still 28c and 14c the area is comfortably warm i notice the outside fan is running at half speed

[bcullen]

just turned it of outside is frozen over, any clues
Bryan

[install monkey]

value 1=-2deg
2=10deg
3=15deg
4=20deg
5=25deg
6=30deg
7=35deg
8=40deg normally in cooling(in uk) when test is started coil value shows 4 and drops to 1 within 4 mins and in heating again the value starts at 4 and rises to 8 within approx 10mins.
standing pressure should be 90-100psig suction press should be 58-60psig(on r22) and 65psig(r407c)
the suction pipe going to the compressor(the fatter one) should be cold to touch(less than 12 deg) and the discharge pipe should be hot(unable to hold) approx 70deg.
u should get at least 10 deg temp difference between the actual temp of the return air(at the filter) and the air off(at the louvre)-normally the accumulator above the compressor(big can) should be cold with a slight frosting. tell us the model number and i can see if i have a manual to send you.
it looks like its short of gas.
check the brass flare nuts on the outdoor and indoor units.sometimes the discharge line fractures near the coil sensor.look for oil stains
good luck

[JoeAT50A]

What's the full model number ?
There is a 3c temperature shift option for return sensor usually used in applications with high ceilings.
Cheers
Stu
Hi Stufus, is there any off setting setting for Mitsubishi Mr Slim products?
If yes, let me know which series/models. I need to off-set the value of return air sensors' readings for my one of the projects. I badly need this feature man. Thank you.

[install monkey]

Hi Stufus, is there any off setting setting for Mitsubishi Mr Slim products?
If yes, let me know which series/models. I need to off-set the value of return air sensors' readings for my one of the projects. I badly need this feature man. Thank you.

joeat50a
which model- city multi units its sw 1-1 to on and repower unit.its different on mr slims,let us know

[bcullen]

Thanks once again mod# PUH-5YK2 All codes seem to be within the allowable limits and no error readings inside (at control) or outside (leds) But i still get a huge disparity between control box readings and the outside fan runs slow causing frost build up and the machine sounds very unhappy and struggling so i turn it off. (when i link 22 it sounds sweet as)
Can all the preasure checks read normal and the unit still be low on gas
Thanks Bryan

[JoeAT50A]

joeat50a
which model- city multi units its sw 1-1 to on and repower unit.its different on mr slims,let us know
I do know this SW1-1 ON to shift from default return sensor TH1 to remore controller built in sensor location to detect.
What I am asking is that I need to off set the value of the defult return sensor, let say -1,+1, +2 and etc.
So far I am wondering whether this features existing on Mr Slim/City Multi models or not.
If so, I really wanted to apply this off set funtion.

[soleowner]

Bryan,

Modifing OEM equipment is not recommended. There are Ph.D's who design the system and program the software that run the inverter compressor to keep the target pressures and temperatures based on room set point and return air temperature. Keep in mind that the sensing elements are a fast reacting thermistor.

What type of remote controller are you using?

What model is the indoor unit?

Are you getting any air deflection to either thermistor?

Have you tried switching the RAT from either the IDU or RC?

Have you been the a training class?

[bcullen]

All very interesting but does not solve my problem of Slow running fan + not defrosting + temp differences
Ta very much Bryan

[install monkey]

what are your running pressures in cooling.suction pipe temp

[stufus]

I do know this SW1-1 ON to shift from default return sensor TH1 to remore controller built in sensor location to detect.
What I am asking is that I need to off set the value of the defult return sensor, let say -1,+1, +2 and etc.
So far I am wondering whether this features existing on Mr Slim/City Multi models or not.
If so, I really wanted to apply this off set funtion.
Hey Joe
It's a fixed adjustment of 3c.
There is no offset adjustment that i'm aware off ,but if you really want to get into it you could introduce a small value resistor into the circuit and play around with it until you get the value you want.
Probably not worth the effort though.
Cheers
Stu

[install monkey]

i think he needs to sort the performance of the system.
coil temp values in test heat /cool are poor.and we havent been told of the operating pressures

[stufus]

i think he needs to sort the performance of the system.
coil temp values in test heat /cool are poor.and we havent been told of the operating pressures
I agree !
The previous post was for joeAT50A and was a reply to a question on offsets.
But there is something strange going on with the system in question as the thermistors in question generally go tits up altogether and not out of calibration.
Id be checking to make sure its the right type and that they are all plugged into the right spots on the board.
Cheers
Stu

[JoeAT50A]

Hey Joe
It's a fixed adjustment of 3c.
There is no offset adjustment that i'm aware off ,but if you really want to get into it you could introduce a small value resistor into the circuit and play around with it until you get the value you want.
Probably not worth the effort though.
Cheers
Stu
Hi Stufus,
Thank you very much, that's valuable info. But I have some sort of 100+ indoor units man.

[bcullen]

Hi stufus and install
I've been hijacked and totally confused by posts.
On thursday the fridgy is checking themisters coil, gas,evap gauge. So i will post after visit.
Bryan

[JoeAT50A]

Hi stufus and install
I've been hijacked and totally confused by posts.
On thursday the fridgy is checking themisters coil, gas,evap gauge. So i will post after visit.
Bryan
Sorry for that Bryan, skip all so called off-topics of me. That will be fine... stufus, install and other members are here to assist your issue. Hope you could able to find out the root of the cause quickly.

[stufus]

No worries Bryan
We all tend to stray off topic every now and then .
But keep us posted and we'll try help you out.
Cheers
Stu