BS box to refnet minimum distance

[r.bartlett]

Gents

Is there a minimum distance that Daikin BS boxes must be from the refnets?

We have a VRVII which the piping has failed 5 times -which we put down to poor pipe- but now it's failed at the refnet so I am now leaning towards fatigue so wonder if the BS box being only 400mm is causing this to happen..

We are going to replace the refnet and add a couple of loops to dampen out any stresses...

Advice most welcome

[james10]

1m if i remember correctly or it could be 500mm i dont have access to my daikin ioms at the moment but you can find them on the daikin extranet also the refnet Has to be within 30degrees of level (15 either way) this may be useful http://www.youtube.com/watch?v=3_TwScCzvUg

[moondawn]

hi james thanks for that you tube clip you put up well worth a watch.

cheers lee

[r.bartlett]

1m if i remember correctly or it could be 500mm i dont have access to my daikin ioms at the moment but you can find them on the daikin extranet also the refnet Has to be within 30degrees of level (15 either way) this may be useful http://www.youtube.com/watch?v=3_TwScCzvUg


Thanks james,

I don't need the water vid thanks as the job is in and the refnets are installed properly just a bit close....

I just like to know if there is a minimum. I have
got this but it doesn't mention anything

http://www.daikinac.com/commercial/documents/eng_data/EDUS39-600-F8%20BSVQ-M%20BS%20Units%20-%20Daikin.pdf

[install monkey]

piping failure-i gather u mean pipe fractures-if so loosen the pipe clips on the main run. in heating mode the pipe temperature causes linear expansion and then fractures.hydrazorb clips are renound for it.

[DTLarca]

Gents

Is there a minimum distance that Daikin BS boxes must be from the refnets?

We have a VRVII which the piping has failed 5 times -which we put down to poor pipe- but now it's failed at the refnet so I am now leaning towards fatigue so wonder if the BS box being only 400mm is causing this to happen..

We are going to replace the refnet and add a couple of loops to dampen out any stresses...

Advice most welcome

This is a very interesting question. If the BS Box is mounted firm and the refnet is too, preventing radial movement, not necessarily preventing axial movement, and the pipe length between the two is short then I wonder if the pipe between the two could ever be too short to bow, so too short to deflect the forces of expansion, but expand enough to stress the refnet to failure.

If multiple pipe repairs have taken place near that refent then maybe there just was accumulative stress from manually working the pipe in the location?

[Mentallist]

There should a minimum straight length of 500mm of piping entering and exiting refnets. Im assuming the fractures you have suffered are in the discharge piping, be sure to check that you have the minimum straight lengths entering and exiting the refnet and ensure this field piping is not clipped excessively. Discharge piping can also be used as LP suction during full cooling operation, therefore temperatures in this pipe can range between 0 and anything up to and in excess of 100 degrees, therefore expansion and contraction can occur, if the piping is clipped too tight or excessively, fractures can occur at the refnet as this is the only allowable point of movement.

[r.bartlett]

the first time I repaired it myself back in Dec 08. This wasn't installed by us as they use a national install contractor. (D1 but we won't go there!)

See pic


Can someone show me this 500mm as I can't find it anywhere and does it have to be 500mm straight. Can we have a loop (or two)

See drawing

[Brian_UK]

Found this, section 5, page 8 and fig 18-3.

http://extranet.daikin.co.uk/en/documents/RQ%28C%29YQ-P_RQ%28C%29EQ-P_IM_3P226891-9J_EN_tcm219-151019.pdf

[Mentallist]

Hi Richard, from the picture it looks as though the fracture is on a bend in the piping, when the bend is pulled this makes this section weaker than the straight sections, therefore, if there is no allowable movement in the piping to allow for expansion and contraction, the stress is is at the weakest part of the piping (The Bend) so fracture occurs. There is no reason why an expansion loop cannot be installed to prevent further failure. I have recommended this on sites before and it has cured issues such as this.

[climarm]

ok , i guarantee that the minimum lenght must be at least one meter distance from refnet to bs box , this is also written in the installation manual of the bs box or in the installation manual of the oudrood vrvII unit . except that , you shoud check if any liquid pipe is messed with an y air pipe (wrong side connections)).... Cheers .