MHI FDCA400HKXRE4 Tech Info Please

[L.JT]

Hey Guys,

Wondering whether anyone can help at all, one of our engineers called today with a fault on a mitsubishi heavy industries vrf saying the unit keeps going out on lp. After asking the engineer the usual questions he cant seem to find a leak although he says there are traces of oil around the suc/dis pipes on the condenser. I'm wondering whether anybody has any technical details on the above unit at all as the commissioning data is not present with the unit and i'm unsure of additional charge weights. Unit has a standard charge weight of 17kg R410A.
I've already done a search on here and couldnt find anything and have also tried 3dair's site and heronridge and mhi's site, does anyone have any other suggestions.

Many thanks in advance.

Lee

[nike123]

Hey Guys,

Wondering whether anyone can help at all, one of our engineers called today with a fault on a mitsubishi heavy industries vrf saying the unit keeps going out on lp. After asking the engineer the usual questions he cant seem to find a leak although he says there are traces of oil around the suc/dis pipes on the condenser. I'm wondering whether anybody has any technical details on the above unit at all as the commissioning data is not present with the unit and i'm unsure of additional charge weights. Unit has a standard charge weight of 17kg R410A.
I've already done a search on here and couldnt find anything and have also tried 3dair's site and heronridge and mhi's site, does anyone have any other suggestions.

Many thanks in advance.

Lee

First you need to find total amont of refrigerant:


5.9 Additional Refrigerant Charge

1. Charge additional refrigerant in the liquid state.
2. Be sure to use a scale to measure the filling amount when adding refrigerant. If you cannot charge all
refrigerant with the outdoor unit lying idle, charge it with the unit running in the test run mode. If operated for a
long time with insufficient refrigerant the compressor will be damaged. (In particular, when adding refrigerant
during operation, complete the job within 30 min.)
3. Fill this unit only with the standard amount of refrigerant (piping length 0 m fill quantity).
Determine the amount of refrigerant to be charged additionally using the following formula and put down the amount of refrigerant added on the refrigerant charge volume recording plate provided on the back of the side panel.
Additional charge amount

http://farm4.static.flickr.com/3285/2782044860_7ba3a5b47f_o_d.jpg

Calculation of amount of refrigerant to be charged in local piping
The amount refrigerant additionally charged in local piping depends on connection pipe size but not on indoor
unit type.
[Amount of refrigerant to be charged in the local piping = Actual length of liquid pipe × Amount of refrigerant
additionally charged per meter of liquid pipe]
[Example] Amount of refrigerant additionally charged = (R1 × 0.35) + (R2 × 0.25) + (R3 × 0.17)
+ (R4 × 0.11) + (R5 × 0.054) + (R6 × 0.022)
R1: Overall length (m) of φ 22.22 liquid pipe
R2: Overall length (m) of φ 19.05 liquid pipe
R3: Overall length (m) of φ 15.88 liquid pipe
R4: Overall length (m) of φ 12.7 liquid pipe
R5: Overall length (m) of φ 9.52 liquid pipe
R6: Overall length (m) of φ 6.35 liquid pipe
Pay attention to the following points in addition to the above for the R410A and compatible machines.
􀂄 To prevent a different oil from entering, please assign dedicated tools, etc. to each refrigerant type. Under no
circumstances must a gauge manifold and a charge hose in particular be shared with other refrigerant types
(R22, R407C, etc.).
􀂄 Do not use a charge cylinder under any circumstances. There is a danger that the composition of the
refrigerant will change when R410A is transferred to a cylindser.
􀂄 When charging refrigerant, use liquid refrigrent from a cylinder. If refrigerant is charged in a gas form, the
composition may change considerably.
Then you need to recover refrigerant from unit and compare recovered amount with required total amount!
After that, find leak or leaks (or maybe you could find leak with good electronic detector before evacuation) and repair. Make pressure test for tightness with nitrogen, at least 12 and preferably 24 hours, with noting ambient temperature at beginning and at end of test. Variation in nitrogen pressure should be 0,1bar/K.

[L.JT]

Hey Nike123,

Thanks for the tech sheet its just what i've been looking for. Have passed instruction to the engineer to recover & weigh out what refrigerant is left within the system, pressurise with OFN and check cond/bs/evaps and all accessable brazed/flared joints for leaks. The only thing we were struggling with was whether any additional charge needed to be added to the system as the commissioning data has not been filled in on the condenser and no data had been left with the client.

Many thanks yet again.

Lee

[BritCit_Juve]

Before that, check you haven't got a problem with the sensor.
Turn the system off and check the standing pressure on your gauges. Then if any of the remotes are the RCE1 version of wired remote
press the check button
press the set button until you get "data loading"
scroll through to item 25 LP sensor using up/down buttons above check button
the reading will be in MPa so times by 10 for bar.
Sensor reading should be close to the reading on the gauges if not faulty sensor or board.
Also as this is a 3 pipe unit chech that all the indoor units cool in test cooling or heat in test heating as the problem could be in bs boxes or the relay boxes. if you dont get either cooling nor heating then check the expansion valve.
If all else fails try the 3d/hrp tech support on 01359272211 as they will at least be able to give you tech info.

Brit

[L.JT]

Guys,

Many thanks for all of your help, managed to find a leak on the first cassette in line on the suction flare, plenty of oil all over the ceiling and god knows how the engineer missed it lol. the system had lost 4.5kgs r410a, fixed leak, pt 650psi for 24hrs vac'd down to 30cfm and recharged 17kgs standard and an additional 10kgs and system is now running sweet. think i'll take him down to specsavers on tuesday lol.

Thanks again for all of your help yet again and hope you all have a good bh weekend.

Lee

[Brian_UK]

Thanks for the update Lee and glad to read that the problem has been resolved.