e4 fault code on daikin super inverter

[Improver]

Hi folks im an improver trying to learn the hard way of how to be an a.c enginneer with no product training just a tech cert and f-gas to my name so go easy on me.. any way i attended a site today to investigate a fault code e4 on wired controller this corresponds to-activation of low pressure switch- the unit is a daikin super inverter model no. RPZ100DV1, Charged with 407c, which is 8.5 bar standing pressure.

My question is what do you think could be the problem?...Because the first daikin tech i spoke to told me to check the continuity on pressure switch but second daikin tech advises that there is no pressure switch and i should check the d.c voltages on the pressure transducer. It is these voltages on the p.t that has left the daikin tech confused and unable to give me a definative answer. And im thinking of changing the p.c.b and p.t at the min but not quite sure. If any one can shed any light on this it would be much appreciated many thanks.

[AbsoluteWDJ]

Hi folks im an improver trying to learn the hard way of how to be an a.c enginneer with no product training just a tech cert and f-gas to my name so go easy on me.. any way i attended a site today to investigate a fault code e4 on wired controller this corresponds to-activation of low pressure switch- the unit is a daikin super inverter model no. RPZ100DV1, Charged with 407c, which is 8.5 bar standing pressure.

My question is what do you think could be the problem?...Because the first daikin tech i spoke to told me to check the continuity on pressure switch but second daikin tech advises that there is no pressure switch and i should check the d.c voltages on the pressure transducer. It is these voltages on the p.t that has left the daikin tech confused and unable to give me a definative answer. And im thinking of changing the p.c.b and p.t at the min but not quite sure. If any one can shed any light on this it would be much appreciated many thanks.

What is the LP when system is in cooling operation?

[Improver]

the system will not run at all and it has been like this for a weeks I know that another engineer has been messing with the units has regassed 1 of the units and has change some sensors. I dont know what sensors and why he needed to change them.

[Improver]

Sorry forgot to mention it started up briefly whilst i was tinkering with the p.c.b but came on in heat mode, i put it on to cooling and got 4.5 bar low side and 15.5 high side and ran for a few mins if that then it cut out and wouldn't come back on allday. Also i couldn't clear the fault on the controller when it miraculously started running.
I had a confused daikin tech on the phone at the time the unit started up and he said the unit shouldn't be running due to the WRONG dc voltage i had at the pressure transducer which is X64A SENPL on the p.c.b.

[AbsoluteWDJ]

Sorry forgot to mention it started up briefly whilst i was tinkering with the p.c.b but came on in heat mode, i put it on to cooling and got 4.5 bar low side and 15.5 high side and ran for a few mins if that then it cut out and wouldn't come back on allday. Also i couldn't clear the fault on the controller when it miraculously started running.
I had a confused daikin tech on the phone at the time the unit started up and he said the unit shouldn't be running due to the WRONG dc voltage i had at the pressure transducer which is X64A SENPL on the p.c.b.

1. When you measured the DC Voltage what pressure did it relate to?
2. What was your actual pressure at time of measuring voltage?

[Improver]

On the p.t plug on the pcb there is 3 wires white red and black. between white and black i had 3.3v dc this is correct as it corresponded to 8.5 bar which i had when the unit wasn't running.
But i should of got 5vdc between red and black but it was open line on my meter this is what confused the daikin tech, he advises that i should have a voltage between r-bk or the system won't run. And when the unit started running breifly this was still open line.

So he thinks that i'm getting the wrong voltage from pcb to the p.t and and the wrong return voltage from p.t to pcb. But he is not sure! and don't know what else to tell me.

[AbsoluteWDJ]

On the p.t plug on the pcb there is 3 wires white red and black. between white and black i had 3.3v dc this is correct as it corresponded to 8.5 bar which i had when the unit wasn't running.
But i should of got 5vdc between red and black but it was open line on my meter this is what confused the daikin tech, he advises that i should have a voltage between r-bk or the system won't run. And when the unit started running breifly this was still open line.

So he thinks that i'm getting the wrong voltage from pcb to the p.t and and the wrong return voltage from p.t to pcb. But he is not sure! and don't know what else to tell me.

Well the easiest answer would be to change both or is there any other outdoor units the same model that you could swap LP transducer to carry out test.

[Improver]

Well i think i'm going to change both that way I won't have to return to site a 3rd time. I'll change the p.t first and see if the fault clears. Thanks anyway.

[james10]

Well i think i'm going to change both that way I won't have to return to site a 3rd time. I'll change the p.t first and see if the fault clears. Thanks anyway.

I would try the board first it would be a shame to drag all your reclaim equipment to the roof to find it's the board

[AbsoluteWDJ]

I would try the board first it would be a shame to drag all your reclaim equipment to the roof to find it's the board

I believe the LP can be changed without having to reclaim.

[Improver]

Yes the p.t can be changed without reclaiming i checked, I am going to change both parts just in case the old pcb has a detrimental effect on the new pressure tranducer. I'll update the page when i have been to site and change the parts i'll let you know the outcome. Many thanks

[1torr]

Hi, if you didn't get 5 volts it sounds like its the board at fault.

[andyc425]

hi mate i had same problem on same system the
PCB on the outdoor condensing unit is not reading the transducer information in the correct manner, causing the system to run in a vacuum mode. recommend replacing the printed circuit board along with the HP & LP sensors. hope this helps

[Improver]

thanks for all your imput on this folks, I thought i gave an update on this ages ago (obviously not) anyways... yeah changed outdoor p.c.b all fault codes dissapeared, system ran fine.