DaddyWarbucks
[FONT=Calibri][SIZE=3][COLOR=#000000]Thought I share this story[/COLOR][/SIZE][/FONT]

[FONT=Calibri][SIZE=3][COLOR=#000000]My wife and I started construction of a new house early lastyear and decided to incorporate an emergency generator after living through hurricanes in the gulf and ice storms in the Midwest… both leading to loss ofpower for several days. Early in the process, I called the local Generac rep and he helped spec out a nice commercial 80kW generator (QT08046ANAX) NG generator and a HTS (HTSN400A3) transfer switch. While the house was being wired, I purchased the transfer switch (last fall) and had it wired in at the time the service was installed. I did not buy the generator at that time because I thought it would be just one more thing thatcould get damaged or stolen from the job site. We moved into the house in March of this year..and shortly afterward I ordered the generator. It arrived and Iinstalled it about a month later.[/COLOR][/SIZE][/FONT]

[FONT=Calibri][SIZE=3][COLOR=#000000]At the time the generator and ATS were specified, the HTS transfer switch was the correct part to use with the generator… but between the time I ordered the switch and the generator (less than 6 months), the HTS ATS was obsoleted in favor of the new RTS NEXUS (load shedding) ATG…and the control system in the generator was changed from the older “H” type to the new NEXUS type. So now I had an older HTS transfer switch and a new NEXUS control system in my generator that was not compatible (understand I ordered the same part numbers that were specified by the Generac rep). I thought surely there was an upgrade path for those of us caught in between. [/COLOR][/SIZE][/FONT]

[FONT=Calibri][SIZE=3][COLOR=#000000]I called the local Generac rep to try to resolve the issue. After several discussions with the factory, and the local rep, I got the following response (and this is verbatim from the email):[/COLOR][/SIZE][/FONT]

[FONT=Calibri][SIZE=3][COLOR=#000000]“The issue is when you originally quoted the job the large liquid cooled units were only available with an H-panel but that has since been obsolete in the commercial line and replaced with the nexus controller. There is no way to make a nexus generator compatible with a HTS switch. You would need to replace the switch with a RTS switch or contactan industrial dealer and order a unit with a H-panel. “[/COLOR][/SIZE][/FONT]

[FONT=Calibri][SIZE=3][COLOR=#000000]Unbelievable. Hard to believe Generac’s response to this was to purchase more equipment. It was obvious to me that this approach was a non-starter. Instead I started down this path: I had the manual for the HTS ATS, and I searched the internet and found a manual for the NEXUS RTS ATS. After comparing the two manuals, I discovered that the main contactor and small control relay (“TR”) were IDENTICAL in both ATGs. Since the new RTS ATG was nothing more than exactly that (the contactor and the control relay, as opposed to the HTS that had that same hardware plus control circuitry for switching, phasing ,loss detection, and RS-422 communication with the older style generators).[/COLOR][/SIZE][/FONT]

[FONT=Calibri][SIZE=3][COLOR=#000000]One night last week I shut off the power to the ATS (via the required disconnect correctly required by any generator installation with a utility) and proceeded to gut all but the large contactor and the small control relay out of the HTS ATG (now while you are scratching your head at this point, understand that I have a Ph.D. in EE and If I could not complete this project, I’d have to give my Ph.D. back). I then rewired the HTS box to look exactly like the RTS switch…complete with test switch (to break the sense lines that now go from the N1/N2 utility connection to the generator NEXUS system) . Interestingly the base level wiring of the HTS even used the same numbering scheme (194, or +12VDC to the “TR” control relay coil, and 23 or contact to ground to switch the ATG from the generator). I was able to salvage and use the small circuit card containing the “TR” control relay, and even left the wiring forthe micro-switches on the contactor to identify what state the ATS was in (not actually used in the RTS, but I use it to send indication to my home automation regarding the ATS state).[/COLOR][/SIZE][/FONT]

[FONT=Calibri][SIZE=3][COLOR=#000000]After the rewiring, I put the generator in AUTO (it went through it’s exercise)… and then flipped the “test” switch in the transfer switch (breaks the sense to the utility). The generator started and switched as it should. Flip the test switch back to “Normal” and it transferred power back to the utility smoothly, and shut the generator down.[/COLOR][/SIZE][/FONT]

[FONT=Calibri][SIZE=3][COLOR=#000000]The morale of this is that, yes if you are one of the people that recently got caught in between product updates, and the factory has decided to leave you stranded like they did me…you can rewire the transfer switch to make it work just like the new RTS (contrary to whatever the factory says). Understand that this does void the warranty on the switch…but then what good is a transfer switch and generator that don’t work together? Not worth 2 cents.[/COLOR][/SIZE][/FONT]
Quote
mastr
Situations like yours are exactly why "2 wire start" became an industry standard years ago.
Quote
phabib
Not to mention showing the difference between low cost consumer quality products and real industrial items that don't change every model year and give their buyers a long end of life warning when a part is going away.

Its a good thing you didn't have to return that Ph.D, if they had an extra one just laying around they'd probably just award it to some undeserving kid who wouldn't know where to start on re-wiring a transfer switch.
Quote
DaddyWarbucks
SO are you saying that the Generac HTS, since it uses an RS-422 line (while technically a "two wire start via communication link") really isn't a standard device?

And, Yes, I'll find some other challenging project to put my degree at risk again in the future. AND...My next challenge is getting all of the home automation stuff to talk to one another. It kinda of reminds me of all the space creatures in the bar in the Star War's movie to talk together...!
Quote
mastr
DaddyWarbucks;11168 wrote:
SO are you saying that the Generac HTS, since it uses an RS-422 line (while technically a "two wire start via communication link") really isn't a standard device?


Generac, according to their own literature made a "marketing decision" years ago to use a non-standard design, thereby virtually insuring a switch sale with every generator.
Quote