Inverter waking up the customer!

[DomB]

So I installed a system with an SMA 3300 inverter in a garage last week and the customer has come back to say that it's waking him up when it kicks in at 06:30!

The inverter is on fire retardant MDF which is screwed to 25mm batons and then mounted on the outside of a brick cavity wall so I didn't think the noise would get through to the inside of the house but evidentally it does. d'oh.

I'm wondering if I can use some rubber mounts or the like to absorb the sound but it's a big heavy inverter so not sure how well they'd survive really. Maybe some sound proofing foam squashed behind the board? Egg cartons?! Maybe I just help him move the freakin' bed?

Any suggestion gratefully received.. (except "move the inverter"!)

Cheers

 

[stretchyboy]

resilient pads like the AC guys use........... should be able to get it from Lindabs or soundspec.info | resilient pads | manufacturers, suppliers & acoustic specifications

 

[edexlab]

Is there a reason for mounting on the mdf board?, could it be fixed direct to the wall ,I have to say i always fix to the wall as i can't see the mdf /other types of board being a reliable way of supporting an inverter for 25 years ,especially the heavier >20kg models ,the only advantage is speed and neatness of install , but this can still be done as neatly on a solid wall with a bit more time spent
And we've never had a complaint regarding the noise /vibration

 

[Worcester]

@edexlab,

Most inverters shouldn't be fixed to mdf, if you are going to use a board, most inverter manufacturers specify that the board needs a 1/2 hour flame retardant rating (not 1/2 hour fire proof) you'll need to get something like Medite FR

 

[edexlab]

@edexlab,

Most inverters shouldn't be fixed to mdf, if you are going to use a board, most inverter manufacturers specify that the board needs a 1/2 hour flame retardant rating (not 1/2 hour fire proof) you'll need to get something like Medite FR

Worcester the point i was trying to make was why fix to a board of any type when there is a solid wall available
I've never fixed to any type of board ,always to masonry using rawlbolts ,or bolted to steel
I am aware of the need to use fire rated mounting boards , as I posted I personally think mounting on boards is'nt a good idea unless there is no other option as some installs I've seen use small screws to hold a 20/30kg inverter onto osb mdf etc, this is an issue I've always discussed with customers when selecting inverter location, and always managed to find a solution ,on one install used a unistrut frame to bolt the inverter to and isolators went onto a separate board
another point is the fire rated board is'nt cheap and if use of this board can be avoided then I would rather the extra money is spent on good quality components etc

 

[Worcester]

@edexlab,

Yep sorry, just wanted to emphasise the point that you can just use plain old mdf.

 

[Marvo]

I agree that the board might be amplifying the vibration. Try some mounts like these and you can use drop-in anchors if it's a brick wall.

 

[edexlab]

@edexlab,

Yep sorry, just wanted to emphasise the point that you can just use plain old mdf.

I'm sure thats a typo and should read " can't" but interestingly I remember reading possibly in the SMA pdf on this subject something about using washers to space the inverter off the wood (non fire rated)
have to say even this I'm not keen on and if it absolutely had to be board mounted i'd use the fire rated stuff
I have seen an install where they used a cement fibre board to mount a 4000tl which i thought was'nt a bad method it was just a shame that they'd got it following the trusses at nearly 45 degrees and used one isolator for the positives and put the negatives
direct to the inverter ,all dc cables were connected via a handy hole in the back of the connection area, made by completely removing the fan incidently the varistors had popped 5 months after date of install ,also customer had no paperwork at all other than Mcs cert

 

[Worcester]

@edexlab,

Yep 'twas a typo should have said "can't" the washers bit is in the SMA Article for mounting on wooden buildings but equally applies to mounting an inveter on any wooden backboard:

View attachment HolzUnt-UEN082610.pdf