Daikin VRV III loud noise diagnosis needed.

[crmont]

This is a 6 ton Daikin VRV III heat recovery heat pump with 6 indoor units and 6 brach selector boxes.

The issue is; Occasionally there is a very loud "trumpet" type of a noise coming from a branch selector box.

It has been a very difficult process to identify the reason behind the noise.

Has anyone out there experienced this issue?


h ttp://hvac-talk.com/vbb/showthread.php?p=7065692&posted=1#post7065692

[hyperion]

See this thread, it may help http://www.refrigeration-engineer.com/forums/showthread.php?t=17505.

[crmont]

See this thread, it may help

Thank you. I've read through all of the messages on this forum. The software update fix has been done and has not fixed the problem.

[hyperion]

If the noise is from only one BSV box, there could be a fault in the box. Its a bit drastic, but you could try changing the BSV box.
Sorry not really much help to you.
Last resort, you could ask Daikin Technical for their suggestions, particularly if they have already been to site to do the software upgrade.

[Mentallist]

The software change made to the BSVQ boxes changes the equalisation operation of the valves. The noise can be ceated if the sub valves are opening/closing too slow and the unit is changing to heating capacity increase/decrease.

Discharge pressure of up to 30 bar can be present behind the valves. The software not only changes the operation of the valves, but also their timing. Factory set, the timing is set to 6 minutes, this is set assuming that the distance between each BSVQ box is > 2m but < 10m.

This timing can be changed in the field settings of the outdoor unit, but as it is a system wide change, all BSVQ boxes are affected, so varying piping distances can affect not only operation, but also noise.

The attending engineer who upgraded the software should have taken this in to account and set accordingly. He should also have connected a service checker and monitored the operation of the system prior to changing the software to check for crossed piping at the BSVQ box.

If suction and discharge piping are crossed, then this "Trumpet" noise will occur as discharge gas will be present at the closed suction valves in the bsvq box. If it is present, discharge gas will slowly (and noisily) begin to push through the valves (Trumpet Noise) until it equalises between the unit and box (noise stops). Capacity in heating will be poor, this will confirm the crossing.

You can also check whether the valves are crossed from the factory, they are colour coded, but check the heads are in the correct position. The top plate can be removed and the helpdesk can advise you of the correct location.

Check the resistance values of the heads, failure of the sub equalising valves can cause noise. Full failure of these valves will generate an "F9" error, so I suspect that this has not occurred fully.

I hope the above helps, let me know how you get on

[crmont]

The software change made to the BSVQ boxes changes the equalisation operation of the valves. The noise can be ceated if the sub valves are opening/closing too slow and the unit is changing to heating capacity increase/decrease.

Discharge pressure of up to 30 bar can be present behind the valves. The software not only changes the operation of the valves, but also their timing. Factory set, the timing is set to 6 minutes, this is set assuming that the distance between each BSVQ box is > 2m but < 10m.

This timing can be changed in the field settings of the outdoor unit, but as it is a system wide change, all BSVQ boxes are affected, so varying piping distances can affect not only operation, but also noise.

The attending engineer who upgraded the software should have taken this in to account and set accordingly. He should also have connected a service checker and monitored the operation of the system prior to changing the software to check for crossed piping at the BSVQ box.

If suction and discharge piping are crossed, then this "Trumpet" noise will occur as discharge gas will be present at the closed suction valves in the bsvq box. If it is present, discharge gas will slowly (and noisily) begin to push through the valves (Trumpet Noise) until it equalises between the unit and box (noise stops). Capacity in heating will be poor, this will confirm the crossing.

You can also check whether the valves are crossed from the factory, they are colour coded, but check the heads are in the correct position. The top plate can be removed and the helpdesk can advise you of the correct location.

Check the resistance values of the heads, failure of the sub equalising valves can cause noise. Full failure of these valves will generate an "F9" error, so I suspect that this has not occurred fully.

I hope the above helps, let me know how you get on

I verified the piping at the BS boxes. All are correct. The tops cannot be removed from the boxes due to an incorrect installation.

Is it possible that the suction and HP/LP at the condenser are crossed? Could a system operate in this condition?

[Mentallist]

It would not be possible for the system to operate fully functionally if main piping run is crossed.

All BSVQ boxes would make the "Trumpet" noise to which you refer to. However, you state in your original e-mail that you only have 1 box making the noise. If you have confirmed that the piping from the refnet to the BS Box is not crossed, then this suggests that the BSVQ is the problem.

I would advise manually testing the EXP heads, this is done by measuring their resistance value. This is in the service manual. If found to be ok, then you may not have any choice other than to change the Box itself as Hyperion suggested, but would be best to confirm that expansion valve heads are on the correct body before doing so, as the box will most likely be requested back, and warranty may be void.

I know of 3 sites in the UK which have had this issue.

[crmont]

I'm assuming the noise is from one box. We actually received a recording of the noise. We cannot seem to duplicate the noise while the technicians are on the site.

The noise is infrequent. A few times a week is typical.

I will link to the recording whenever I get to 15 posts.

[Mentallist]

Try operating the unit in heating with a high set point, then when capacity is produced by the unit, change to cooling. I would envisage the noise will then be created. Works for me?

[HVACJOEK]

I had a similar problem with a heat pump years ago it turned out to be a defective check valve that would stick and make a load "trupeting noise" I replaced the valve and all was well.

However Daikin software upgrades seem to correct some of the noise complaints from "BSVQ" boxes.

Keep in mind the BSVQ box is basically the guts of a heatpump.

[icecube51]

do a check-up whit the Daikin service checker to see if the valve's are operating correctly. this can be done in heating or cooling mode.

Ice