Really good video . DSH is a new item I’ve been running into on VRV and Daikin applied equipment. This really helped me bridge my knowledge gap , thank you!
Hi Roman, this is brilliant. Thank you for the content. I started service checker analysis about a year ago when I started working at Daikin and it took me a while to get the hang of it. I've gotten alot better at it but this video hear made so much sense. Thank you once again. Keep the videos coming 💪
@@po65231r Hey mate, K doesn't relate to F at all, K is absolute C, so if a water chiller (for example) has 12C entering and 6C leaving water temperature, this could be expressed as 6K of duty (12-6). 0K = -273C (absolute zero), 273K = 0C, 373K = 100C and so on. Cheers.
Hey Roman. When I’m using my service checker on a VRV 4. I have noticed the eev pulses have 2 sets of data. Eg it has upper heat exchanger eev pulses, and then upper heat exchanger eev US pulse. What does the US dictate? I don’t use it in my diagnosis, I’m just curious to what it refers too.
Great video! Thanks for sharing. Are these numbers different when unit in heating mode? I always see outdoor coil iced up after the main eev, and from service checker, it shows the valve 3000 pls
The measurements discussed in this video are universal between all modes, however where we are measuring these temperatures changes. Measuring subcooling in cooling mode is using different temperature measurement locations than in heat mode.
1:34 - Where do you put your probes to get the numbers for calculating discharge superheat? My understanding of the discharge superheat calculation is discharge line temperature less liquid line pressure (converted to temperature). Is that right?
Discharge superheat is measured using discharge line temperature 6” down stream of compressor then subtracting it from liquid line temp converted to saturation temp. 180-110 = 70 DSH.
Without getting into the math, Daikin has two apps that can help you convert that. Daikin tech and Daikin services, it’ll convert dc voltage to pressure (vise versa) and temps to ohm (vise versa). Then get gauges or temp probes and see if they correlate.
I’ve got a total of 9 systems of 4X heat recovery units. We have had multiple issues and lost compressors. Your video made me dive deep into these systems. One system in particular is running a high DSH 90-100. SSH is within range no higher that 32 sometimes drops less in five. Subcool is within range. I did an oil differential across the suction line and was getting 7F then jumped up to almost 40F. Do you have any more info. Also where did you get the 30 modes local Daikin rep doesn’t have it.
Sounds like oil traps within the building. High DSH levels with normal range SSH and Subcooling means your compressors are low on oil. Sounds like piping errors or discrepancies. Meaning there are piping rules broken causing oil to become trapped in the system. Your local Daikin Rep will not have that list, as I translated it from Japanese. Daikin Japan is the only one with the list prior to now.
VRV DSH Discharge SuperHeat Discharge pipe temp - Tc ( condensing saturation temperature) Range 27-72 Below range ( overcharge) Above range ( low oil or low refrigerant) SSH Suction SuperHeat Suction pipe temp - Te ( evaporation saturation temperature) Range 3.6-32 (5-32) Below range (wet- liquid refrigerant at compressor)(overcharge or bypassing refrigerant In system) Above range ( low charge or restriction in system) SUB System SubCooling Tc - liquid pipe temp after heat exchanger(s) Range 11 +/- 3 Below ( undercharge or restriction ) Above ( overcharge or bypassing )
System never runs the compressor over half speed causing velocity to be low not allowing refrigerant to bring oil back from the indoor units. Couple that with liquid flood back then compounds the issue removing any remaining oil from the compressor.
@@RomanBaugh I only say that because there's been some other helpful daikin content that was taken down. I don't understand the secrecy. We as technicians need any tools we can get, thank you!!
Do you know the process of Daikin minisplit, how do they calculate evaporating temp and condensing temp. Since they do not have pressure transmitters. Only discharge probe, ev probe and condensing probes, and air thermistor probes. Do they calculate evaporating and condensing temperatures via the compressor load ampere, and also take into account the heatexchanger probes? Its bugging me for real. Hope you have somewhat of an answer.=)
Short answer is they don’t. Thermistor data is all that is used to control the motor speeds and valve pulses. At least that’s what is taught in the mini split class.
@@ryanbrown7134 Then how can they get correct sh and sc? Its been bugging me how are they actually know how to adjust the eev. Some of the data needed for correct sh, sc is unknown. They must use ampere drawn by the compressor too trying to get somewhat of correct ev pressure and condensing pressure... 😁
@@guuuuustaf It bothered me too when I first started working on them. They don’t monitor superheat or subcooling. They may have an algorithm that determines wet operation with compressor current and discharge temp but I doubt it. Even if they did, they wouldn’t tell us anyways. Other than the logic, mini splits are very simple units.
Haha okeey thank you for the answer=). may be therefore they often have two accumulator tanks beside compressor. Cause the sh cant always be 100%.They are indeed very simple. The logic as you say is the more tricky part. @@ryanbrown7134
If the units don’t have the pressure sensor , it should have thermistor at the evap and at the condenser coil . These temperature will be used for evap temperature and condensation temperature instead pressure reading converted into sat temperature.
@@epicone2449 looked for the dsh, sc and sh on a daikin fit heat pump couple days using the daikin btsc app. The symbols arnt matchin on the app. Reverted to just using to probes. Went after the dsh and sh in heating mode. Looked normal. Last tech suspected low charge after the tstat error history shows low pressure trip. Found the data wire was grounded at the equipment chasis and corrected it.