Vaillant engineer arrived today.  He change the control board and harness for the compressor.  This did not fix the problem.  So next step is for the inverter to be changed. However, there is a problem!

The Vailliant engineer found 20 volts being inducted into the EBUS cable.  This is a result of the EBUS cable being in the same outside wall trunking as the mains feed (about 2.5m).  The manufacturers specs states that the 2 cables have to be separated by at least 120mm. 

Vaillaint will not come back until this is fixed.

Posted by: @trebor12345

↑

The Vailliant engineer found 20 volts being inducted into the EBUS cable.  This is a result of the EBUS cable being in the same outside wall trunking as the mains feed (about 2.5m).  The manufacturers specs states that the 2 cables have to be separated by at least 120mm. 

Ooh interesting.  Installer is going to have to fix that I presume.  Is there any suggestion that this could be the only problem (in which case Vaillant may want to charge the installer for nugatory work!).  

Posted by: @jamespa

↑

Posted by: @trebor12345

↑

The Vailliant engineer found 20 volts being inducted into the EBUS cable.  This is a result of the EBUS cable being in the same outside wall trunking as the mains feed (about 2.5m).  The manufacturers specs states that the 2 cables have to be separated by at least 120mm. 

Ooh interesting.  Installer is going to have to fix that I presume.  Is there any suggestion that this could be the only problem (in which case Vaillant may want to charge the installer for nugatory work!).  

Myself I don't believe that it's an induced voltage in the EBUS.  The installer is coming Thursday to reroute the cable.

Posted by: @trebor12345

↑

Myself I don't believe that it's an induced voltage in the EBUS.  The installer is coming Thursday to reroute the cable.

I'm inclined to agree.  Poor bus design that can't survive this.  I know you are supposed to separate mains and signal cables, but I bet a lot don't.   I guess that they also say any old 2core cable doesn't help, if it were screened or twisted pair it would be more resilient

Posted by: @jamespa

↑

Posted by: @trebor12345

↑

Myself I don't believe that it's an induced voltage in the EBUS.  The installer is coming Thursday to reroute the cable.

I'm inclined to agree.  Poor bus design that can't survive this.  I know you are supposed to separate mains and signal cables, but I bet a lot don't.   I guess that they also say any old 2core cable doesn't help, if it were screened or twisted pair it would be more resilient

 

The manufacturer should specify a screened EBUS cable (IMHO).

Posted by: @trebor12345

↑

The Vailliant engineer found 20 volts being inducted into the EBUS cable.

Without information about where and how it was measured, this is useless. Don't even know if DC or AC.

EBUS has 20VDC between the two wires when idle, so if it the measurement is "20V DC between the two wires" then yeah it means the device at the other end of the cable is powered and the cable is connected, good news, everything works fine... 🤣 

EBUS does not use differential signaling, it's plain old single ended 2400bps serial, so twisted pair is not likely to bring any benefit (no drawback either). Best protection against interference would be coax. You could also use a 2 conductor shielded cable but shield needs to be connected at both ends to "-" terminal. Strange they didn't go with cutting edge technology from 1983 like RS485 or CAN like everyone else. RS485 works fine on dirt cheap SYT telephone cable ziptied to three phase AC cables... 

Posted by: @bobflux

↑

Posted by: @trebor12345

↑

The Vailliant engineer found 20 volts being inducted into the EBUS cable.

Without information about where and how it was measured, this is useless. Don't even know if DC or AC.

EBUS has 20VDC between the two wires when idle, so if it the measurement is "20V DC between the two wires" then yeah it means the device at the other end of the cable is powered and the cable is connected, good news, everything works fine... 🤣 

Not my area of expertise, but it was measured between the plus and minus of the EBUS cable to Earth. Cant remember if it was AC or DC, but I think AC.

Installer called this morning and has move the 2 cables 120mm apart.  System has been started and switched off 3 times and its working.  So now in monitor mode.

Posted by: @trebor12345

↑

Posted by: @editor

↑

If it were my system I’d be straight on to the installer and Vaillant support. A three-week-old heat pump really shouldn’t be throwing faults like that.

The installer has just called and noted an error code of F.753, which means there is fault with the outside unit (communication has been lost between the main heat pump control board and the inverter/frequency converter board).  Vaillant have been contacted and will attend site on Wednesday.

Just curious, is your installer a small local one or a major one?

Posted by: @trebor12345

↑

Posted by: @jamespa

↑

I'm inclined to agree.  Poor bus design that can't survive this.  I know you are supposed to separate mains and signal cables, but I bet a lot don't.   I guess that they also say any old 2core cable doesn't help, if it were screened or twisted pair it would be more resilient

The manufacturer should specify a screened EBUS cable (IMHO).

the new vaillant models pro and the new plus use modbus for this communication to the odu, so it seems this will make it more robust to installers trying to cut corners.

I am also pretty sure vaillant also do a “pipe with signal cable” combined option to stop ac induced currents - as not even a rookie installer would want to be found running power cables next to hot water ones… 😉 

Posted by: @batpred

↑

Posted by: @trebor12345

↑

Posted by: @editor

↑

If it were my system I’d be straight on to the installer and Vaillant support. A three-week-old heat pump really shouldn’t be throwing faults like that.

The installer has just called and noted an error code of F.753, which means there is fault with the outside unit (communication has been lost between the main heat pump control board and the inverter/frequency converter board).  Vaillant have been contacted and will attend site on Wednesday.

Just curious, is your installer a small local one or a major one?

 

I would say a medium company of around 20/30 employees.

As expected it failed to run late yesterday with the same fault codes.  So inverter to be changed on monday.