Leave the hash boards unplugged and just power the controller/IO board.
Do the lights on the LAN jack start up with the green one (network active) blinking?
Does the little blue light next to it eventually light?

If no, methinks controller is probably bricked or dead.
You said the fans work and red LED's on the IO board light so I'd think it is probably OK. The bank of green LED's (not lit I assume) shows coms activity.

Liquid cooling of any sort 101:
For now, putting aside how heat is getting into the primary fluid to-air cooling loop be it direct contact using cooling blocks, oil-immersion fluid to air, or a 2-phase liquid/vapor 'Hot side' to fluid to air setup:

#1) All heat flow calcs are based on using either BTU/HR or for heat loads over several kW, Tons
2) Conversion factors:
  1kW = 3412.142 BTU/hr
  10kW = 2.84345 Tons
  A handy site is http://www.rapidtables.com/convert/power/kW_to_BTU.htm and http://www.unitconversion.org/power/kilowatts-to-tons-refrigeration-conversion.html

That covered, we come to basic laws of heat transfer between two objects or mediums. Again, for simplicity media heat capacities, thermal resistance of the heat exchangers used, Heat exchanges size and even flow rates is left out.

That leads us to:
3) Based purely on what temp we want to maintain at the load (miners) vs the temp the sink or where the heat is going  (outside air, a large pond, a swimming pool, etc) the general rule is:

The amount of heat energy (power, BTU's whatever) that can be moved is directly related to Temp_load - Temp_sink or more commonly referred to as Δt.

Now to apply these basics to miners, 1st remember that:
a) miners are quite happy at say, 61C (141.8F). That's pretty toasty and more than uncomfortable to the touch.
b) Even using an extreme sink temp - in our case, eventually ambient air - of 50C (122F) we still have a pretty decent Δt With a more reasonable ambient air temp even better.
c) That in turn means we only have to dissipate enough heat into the sink (air) by using a honking big outside fluid-to-air heat exchanger to keep the desired miner tank temp where we want it. At a minimum you will need desired temp and Δt between that and the sink (air) along with BTU's or Tons to be dissipated to start sizing a radiator or cooling tower.

In summary, given that it is MUCH easier to transport massive amounts of heat energy in a fluid moving through pipes vs just moving a massive amount of air it gives a huge advantage where feasible or appropriate. Liquid is of course much more compact on the load end (miners packed in tanks) and pipes are a helluva lot smaller/easier to route than air ducts. Only really big part is the sink end but since that is outside, not a huge issue to deal with.

To be continued...
  

No doubt that the Chinese farms are a monster market that needs to be taken care of but not all mega farms are in China or Asia in general folks... Get over it.
ref: https://bitcointalk.org/index.php?topic=1566654.msg15721138#msg15721138
which is a 5MW farm being built in Labrador. Power there is $0.025 per kWh
They mention when full will hold "Thousands of s9's"

Yes the controller can be powered up by itself to see if it is dead or alive. Just leave the hash boards all unplugged.

As for parts, if you take a quick look through Bitmains site starting at the Support tab > Service, you eventually find https://shop.bitmain.com/product.htm?parts=parts

Along these lines, just how much does ShareDiff affect actual 'work' (power used) load? If the dif is not too hard and share rate is too low do the ASIC's spend time idling and just twiddling their thumbs so to speak?

I know that Antpool samples throughput every 1/2hr and as a result ShareDiff bounces up and down pretty wildly whereas on Kano it changes every minute or so. On Antpool the diff would often go up down 25% or more and stay there for the 1/2hr, Kano, just a few % each change. Naturally, more samples in a shorter time translates to better and more accurate averaging response time...

Damnit, now ya got me thinkin' again...
Ya know, the s7 is pretty much the same hash board design and I have a few spares here...

The longer backside sinks, easy to replace with custom water blocks.

Topside -- cannot be removed without damage. So, a custom block with something such as a putty-like thermal gap-filler from Bergquist or such to mostly fill the existing chip sink fins and xfr heat to a block on top of them? Not as good as direct block contact with the chips but still far better than pushing air over them.
Hmm...

Possibly related to most pools limiting the share rate each miner gets? Done to smooth out the pool servers data loading and keep it reasonably fair for the wide range of miner speeds folks are using. I *think* most try and keep it around 8 shares/sec by adjusting the ShareDiff higher/lower as needed to average that share rate, no? That in turn limits how much 'work' the miner is doing at any given time.

When Solo mining I'd hope the only throttle is the miner vs pool access fairness...

Just looked into the Restricted API access and speed changes using Awesome Miner: You need either the Professional Edition or higher to use those functions. Looks like time for me to bite the bullet and upgrade from Standard to Premium (good for 20miners per-site).

Nice thing is that Premium also unlocks remote access for monitoring/rebooting my farm at work

Have you tried powering just the controller board and while leaving the hash boards un-powered, pressing the reset for >10sec? That seems to have unbricked another person's s7 here.

From their site "patented 256 colors RGB fan".
PATENTED??? How the hell did something as common as RGB modulation of LED's in a fan or whatever get a patent??? 

No idea why it took so long, luckily my 2 warranty issues with a s5 and a s7 were handled within 2 weeks. I do see that in the Forms to fill out for service Bitmain has added several 'special instructions' to the WO form... https://cnshop.bitmain.com/workOrderGuide.htm

"Shipping way:
UPS,DHL,FEDEX,EMS, TNT, USPS, or your local post office are available.please note that EMS and USPS provide poor service in HK,we cant ensure they can delivery the parcels in time.
NOTE:
1.   Be sure mark "deliveries are made on working days only" and "Antminer" on the items description of
      the waybill.Otherwise we wont accept any delay due to missing of these info .

2.   It's necessary to package the hashboard very carefully. We can not repair if the PIN on hashboard is lost because of the shipping problem. Please claim to your logistics agent if the PIN is lost on the way.
3.  The HongKong warehouse only responsible for receiving the parcels ,we wont accept "Freight Collect",please pay
      the shipping cost in your side. Please mark the warehouse NO. 3811
Consignee: (The package will be rejected if there is no "No.3811"; The PSU can not be packed with other stuff in the same tracking number because of customs clearance)
Name:FUKWOK KWONG-No.3811
Company Name:TUNG-D INTERNATIONAL DEVELOPMENT LIMITED Warehouse No.3811
Address:Unit 104, 1/F, Sunbeam Centre, 27 Shing Yip Street, Kwun Tong, Kowloon, Hong Kong
Office Tel:+852-2750 5059 (The number is only available for logistics not for service )                
Warehouse:Tel: +852-2750 5150(The number is only available for logistics not for service )"

That looks to open a lot of loopholes for them to claim 'lost in transit'....
PIN?? as in the barcode sticker on the boards??? What would a logistics company have to do with that?

Now as to getting back a different board:
Well, ja. That is how most often any electronics servicing goes. Rarely is any board repaired and sent back. Even using low-cost labor it is usually just not worth the time to do more than verify a board is dead. So, either a re-worked board (from production problems or returned boards from other customers that were able to be fixed) is returned to the customer or if really lucky -- a brand new one is sent.

Of course given that test/replace (not repair) is the norm, the question still remains why it took so long for Bitmain to get a replacement out to them?

Now considering that ^^ was in reference to a post from Tupsu who is certainly NOT a friend of Bitmain, rather amusing aye-what?

Since it appears that this idiot is of the opinion that anyone not jumping on his honey truck to join them in the crap slinging has been paid off or whatever, now Ignored here.

What a yutz...  

Proof of no s9 sales to China? Without that you are just trolling.

Zero interest in your idea

That violates every countries National Electric Codes. For power wiring a neutral must ALWAYS be tied to a ground at the incoming power panel. That is what makes it a Neutral vs just another Hot wire...

Technically, the major distinction between Neutral and Ground wires is that Neutrals are for carrying current whereas Ground is strictly a safety wire.

What you described is commonly referred to as 'isolated power' and is restricted for use only with very sensitive test equipment. A variant of it is an isolated ground setup (usually orange power sockets) that is much like you described except the neutral is still tied to ground but with care that the Neutral/Ground bonding only happens at 1 location.

As to single phase PSU incoming power connections -- Makes no difference if L1 or L2 are Hot and the other is Neutral.

Access to free power is a really good start to making money mining.

That leads to parts 2 and 3 of the equation:
2) How much power/is it in a readily accessible area for miner maint?
   and
3) Heat removal from using said free power. Remember that miners are 100% perfect heaters -- all power fed in comes out as heat. A LOT of it!

Ouch!
I know the last 2 s7's I bought (b18) are set to Restricted as well as 1-2 others from earlier batches.

To do it I assume I'd use PuTTY to SSH in but from there...
Where is the config file located?
What editor and more to the point, what commands are used to change the permissions?

And of course, wonder if this works with Bitmain's fork of Kano's CGminer on the s9? ...

Most likely need to change the s9 miner software from Restricted API access to Privileged same as some s7's need done?

Just so ya know -- some s7's and all s9's operate in a restricted (vs Privilaged) API/SSH access mode... All operating data can be read but not all can be changed & saved outside of using Bitmain's GUI.

My s7 b18 is one of them. M's Miner Monitor simply does not see it and I believe one from an earlier batch is the same. It also has never seen the s9's and since that program has been abandoned, that leaves Awesome Miner Monitor.

Finally pointed Awesome at the s7 batch 18, yep. It sees it and reports it as restricted access.

Gotta change that and the website for Awesome has some info on it http://www.awesomeminer.com/help/minerapi.aspx
but.....
a) does the privilege hack work for the s9?
b) what 'ux is Bitmain using? What editor is in it? What are the edit commands...
c) What is the file to be changed and where is it located?

Ant tools can set the voltage on s9's?
Even though I got the v0.16 zip from Bitmain, the program shows v0.14 in the Title bar and the pull down for Miner Type only goes up to s7.

 So it works for the s9 as well? Using what miner type -- s7?
Also, do the settings stick through a hard reboot or does Voltage go back to the default?

Curious minds want to know...

With BTC currently = ! 610 USD that may take awhile... Eeep!

Or... they are fulfilling order for mega customers like https://bitcointalk.org/index.php?topic=1566654.msg15721138#msg15721138 and https://bitcointalk.org/index.php?topic=1566654.msg15764113#msg15764113.

Not to mention of course probably Hashnest.

"Several thousand s9's' is a helluva lot of chips and with TSMC no doubt having a monthly production limit set for Bitmain's boutique ASIC's, well you get the picture...