Daikin vrv 2 j4 fault

[wilks]

I'm trying to resolve a current issue we have with a daikon vrv2. It's showing a j4 fault . Outdoor Low pressure saturation thermistor. So I rang up technical because I wanted to check the resistance of the thermistor( I was ringing to check what range they should be at my applied temp.) But I was then told that j4 is a problem with the gas , technical didn't seem to want to explore any other possibility , just kept going on about the gas " young sir "! Said about reclaiming and checking weight that's on commissioning sheets. So my question is this . Does anybody know what range these thermistors should be at? And has anybody else come up with the same problem? Thanks

[VRVIII]

-5 = 85Kohm
0 = 65Kohm
5 = 51Kohm
10 = 40Kohm
15 = 31Kohm
20 = 25Kohm
25 = 20Kohm

[wilks]

Thanks vrv3.

[wilks]

There is a master and a slave unit piped together , I take it the master is the one with f1 f2 wired up to the indoors. Is there any way of checking which set of thermistors might be suspect? Obviously there is a set for the master and slave. ? On the I control it's showing address of faulted unit at 000?thanks for your help.

[install monkey]

wilks, ive checked a few vrv2 service manuals and no j4 error listed. is on vrv3 thermistors- r2t and r11t on each outdoor req checking- ill try and send u the manual so you can view for yourself

[martinw58]

had same fault was thermistor a42 heat x thermistor but this is a common thermistor fault on out door unit so need to chech them all

[wilks]

Thanks for your help . So It's more likely to be a thermistor rather than a gas problem. Not worked on many vrv2 s before, Insto monkey , it's defiantly a vrv II like. Thanks lads .

[VRVIII]

If the outdoor unit is a VRVII 3 pipe heat recovery system REYQ - - M7W1B, error code J4 relates to the heat exchanger gas pipe thermistors R81T main heat exchanger (top) or R82T sub heat exchanger (bottom). The thermistors in question are located on the pipe section between the reversing valve and the heat exchanger, If any of these thermistors go out of range a J4 error will be generated.
As you have a multi system with 1 x master and 1 x slave you have 4 gas heat exchanger theristors in total. If you look in the correct service manual Si39-306 there is a section which explains the outdoor fault retrieval procedure, this will allow you to identify which thermistor and module is causing the error.

[install monkey]

sent you that too si39-306

[wilks]

Thanks again lads . Much appreciated .