Technibel Climatisation GRFMI 1158 R7I, Service Manual & Test Run Service Manual

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7 - 10
2-WAY MULTISET VRF SYSTEM
Trouble Diagnosis
7
H06 Alarm
Alarm code H06
Alarm mea n i ng Ab n ormal low-pre ssu re drop
Alarm co n ditio ns A pre-trip occ u r s d u ri ng the un it’ s operatio n whe n the low-pre ssu re s e ns or i ns talled at co ns ta n t
low-pre ssu re part s detect s a pre ssu re of 0.05 MPa or le ss co n ti nu o us ly for 2 mi nu te s ,
or a n i ns ta n ta n eo us pre ssu re of 0.02 MPa or le ss . (The s e val u e s repre s e n t ab n ormal low pre ssu re
which may dama g e the compre ss or.)
However, the alarm doe s n ot act u ally occ u r the fir s t 2 time s that the above operatio n take s place.
At the s e time s , the o u tdoor un it i s s topped a n d the co n ditio ns are mo n itored. The alarm occ u r s
whe n the above operatio n occ u r s for the third time. The fir s t 2 time s before the alarm occ u r s are
called “pre-trip.” After pre-trip occ u r s , if the low-pre ssu re s e ns or detect s a pre ssu re of 0.15 MPa
or more for 3 mi nu te s of co n ti nu o us operatio n , the pre-trip co un t i s re s et to 0.
If the low-pre ssu re s e ns or detect s a pre ssu re of 0.16 MPa or le ss co n ti nu o us ly for 60 mi nu te s
whe n the compre ss or i s s topped, a n alarm occ u r s immediately ( n o pre-trip).
Probable ca us e The un it low pre ssu re ha s dropped to a level that doe s n ot occ u r un der ordi n ary co n ditio ns .
(1) The ab s ol u te amo un t of g a s i n the s y s tem i s too low (a s a re su lt of i nsu fficie n t refri g era n t
char g e or leak).
(2) The refri g era n t ha s acc u m u lated i n the circ u it a n d ha s n ot ret u r n ed to the compre ss or.
Refri g era n t ha s acc u m u lated i n a locatio n of o n e-way flow a n d ca nn ot e s cape.
Hi g h-pre ssu re level i s low, re su lti ng i n poor flow of refri g era n t i n the circ u it. (A lower hi g h-
pre ssu re level re su lt s i n a s maller differe n ce betwee n low pre ssu re a n d hi g h pre ssu re, that
may be i nsu fficie n t to ca us e refri g era n t flow.)
( 3 ) The refri g era n t circ u it ha s become clo s ed, a n d refri g era n t ha s n ot ret u r n ed to the
compre ss or. I n s ome ca s e s whe n moi s t u re e n ter s the refri g era n t circ u it, it ca n freeze at the
low-pre ssu re locatio ns a n d the re su lti ng ice ca n block the circ u it.)
If the alarm occ u r s whe n there i s su fficie n t refri g era n t i n the s y s tem ((1) a n d ( 3 )), liq u id
refri g era n t ha s defi n itely acc u m u lated s omewhere i n the s y s tem. Liq u id refri g era n t g e n erally
acc u m u late s i n hi g h-pre ssu re locatio ns . I n thi s ca s e the hi g h pre ssu re g rad u ally i n crea s e s
(however it may n ot i n crea s e if the locatio n where the liq u id acc u m u late s i s su fficie n tly
lar g e). Depe n di ng o n the refri g era n t s at u ratio n temperat u re, it may al s o acc u m u late i n low-
pre ssu re locatio ns . I n thi s ca s e the hi g h pre ssu re i s un likely to i n crea s e.
Check (1) Check that the s ervice valve i s ope n .
(2) Check that n o n e of the valve s (mecha n ical valve s ) i n the mai n refri g era n t
circ u it i s clo s ed d u e to a n operatio n fail u re.
( 3 ) Check that there i s n o po ss ibility of forei gn object s or water havi ng e n tered the refri g era n t
circ u it.
(4) Check that valve leaka g e at a s topped su b un it ha s n ot re su lted i n acc u m u latio n of
refri g era n t at that su b un it.
(5) Check that n o refri g era n t leaka g e ha s occ u rred.
Correctio n (1) If there wa s a valve operatio n fail u re, i n g e n eral it i s n ece ss ary to replace the valve.
(2) If a forei gn object or moi s t u re ha s e n tered the circ u it, i ns tall a s trai n er or dry core (depe n di ng
o n the de g ree of the problem).
( 3 ) If refri g era n t ha s leaked i n to s topped su b un it s , it i s likely that valve leaka g e ha s occ u rred.
The valve m us t be replaced.
Example
Note
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1. 2WAY VRF DCI Alarm Codes