Vaillant geoTHERM Installation Instructions Manual

Also see for geoTHERM SERIES: System Installation Instructions Installation and servicing Instructions for use Operating instructions

Contents

Fault diagnosis and rectificationInstallation instructions geoTHERM 0020051574_04 10111Fault code Error text/description Possible cause Solution28 Coolant pressure too lowBrine side/well water side issupplying too little heat.The integral low pressure switchhas tripped at 125 kPa (1.25 bar)(g).(VWS only) Air in the brine circuit.Brine fluid concentration too low.> Bleed the brine circuit.> Check the brine fluid frost protection andincrease the brine concentration if necessary.(VWS only) The pump output of thebrine pump has dropped or the brinepump is faulty.> Check the brine pump, and replace if neces-sary.(VWS only) Not all circuits are circu-lating equally. Can be seen from thedifference in the severity of icing onindividual brine circuits.> Adjust the brine circuits.Not all the required stop valves areopen.> Open all stop valves.Coolant flow rate too low (e.g. ther-mal expansion valve TEV incorrectlyadjusted or faulty).> Have the coolant circuit checked. Inform thefactory customer service department.For VWS/VWW 38/2 and 46/2 only:The fault relay on the in-rush cur-rent limiter has responded.The red LED on the in-rush currentlimiter is flashing:2x = Incorrect phase sequence3x = Compressor motor overcurrent4x = Thyristor module excess tem-perature5x = Low voltage/phase failure6x = Min./max. power frequency7x = No compressor connected> Check whether the green LED on the in-rushcurrent limiter is lit. If the green LED is notlit, there is no power supply or the in-rushcurrent limiter is faulty.> Check the power supply and restore.> Check the in-rush current limiter and informthe factory customer service department ifnecessary.> VWS/VWW 38/2 and 46/2 only:If the green LED lights up and red LED isflashing, find the cause in the list of flashcodes above and rectify the fault, and informthe factory customer service department ifnecessary.29 Coolant pressure outside therangeIf the error occurs twice in arow the heat pump cannot bestarted until after 60 min. atthe earliest.Coolant pressure too high or too low,all causes mentioned at fault 27 and28 are possible..See faults 27 and 28.11.3 Fault with temporary switch-off