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I think the first one was malfunctioning from the "O" wire arcing to ground(check pics again), the replacement had all relays on at once. Like I said, there's no problem with the wires from the stat to the unit, it's the stat. I even took off the board covers inside the stats looking for a switch, a jumper or something for a solution.
If I could use some other stat I most assuredly would, this retailer requires LightStats in all of their establishments, no others are allowed under any circumstances.

See Will , Light-Stats are a pain...


No kinda jumpers on the back side of the terminal strip huh..? Kinda strange this stat doing same as first...Might be time for new control wire.... and a different kinda stat....

Went out first thing this morning to replace the LightStat at this store. I swap 'em out and turn the unit back on and set it to heat. I get both stages of heat but, I have that little nag riding my shoulder so, I check the output from the LV terminals in the Stat, I have 24v to common at every one of them. I turn it off and kill the HV, go up on the roof and take wires loose at the unit LV terminals. I check for shorts in the wires, re-trace the thermostat wire and I don't find anything. Get back to the stat, take off all wires but R and C and turn it back on, I still have 24v at all terminals to C. I moved the setpoint to stop heat with fan on "auto" and W1 & G dropped out but Y1, Y2 and W2 all had 24v to common with no calls for any operation.
I called LightStat tech support and they are sending me another stat overnite with some return labels to send them both LightStats back so they can look at them. I'm curious to know what the heck is going on here too!

Originally Posted by swellmel

When I first started my last maint job, I had a larger chain store that had what appeared to be a roof leak. After an attempt to find the leak after it stopped raining, I finally went in their while it was pouring down hard. Went up a ladder and removed ceiling tiles and tracked down the leak source. It was an electrical box coming from the RTU 10' away.
When it was dry out, I went to the RTU and found the disconnect with the wires running through knockouts without a connector. The water was running behind the disconnect and into the unit and down the 120v conduit.
So the leak that no one found in 8 years(yes, 8 yrs) got repaired.

I had a similar problem at a different strip mall. The tenants complained of a gurgling noise in the breaker panel and water leaking out of this panel. I get there, turn on the blower and yep, it's got a gurgling sound in the panel. I take off the panel cover and use my siphoning hose to find the source, it's the conduit up to one of the RTUs.
I go up on the roof and pull panels, that unit the electrician had drilled an entrance in the base pan of the blower compartment. He used a connector but, the filters were slap stopped up and the condensate pan had overflowed into the blower compartment and down the conduit to the breaker panel. Bad thing is, about 6 inches over, in the control compartment, there is a knockout island for electrical and control entrances that is completely isolated from the blower compartment, too lazy to do it right I guess.
I unplugged the condensate drain, cleared the water from the base pan and told the tenant to tell the landlord to get the electrician out there to fix that most dangerous situation they caused. Haven't been back since.

Originally Posted by william antley

I'm often surprised that the sparkies and hacks will take the time and trouble to drill holes in the worst possible location to pull wire through but won't bother to use a bit of seal-tite or connectors to keep rain from entering the building through the units I'm now responsible to maintain and repair.

When I first started my last maint job, I had a larger chain store that had what appeared to be a roof leak. After an attempt to find the leak after it stopped raining, I finally went in their while it was pouring down hard. Went up a ladder and removed ceiling tiles and tracked down the leak source. It was an electrical box coming from the RTU 10' away.
When it was dry out, I went to the RTU and found the disconnect with the wires running through knockouts without a connector. The water was running behind the disconnect and into the unit and down the 120v conduit.
So the leak that no one found in 8 years(yes, 8 yrs) got repaired.

we know how this happens

Its every when retailer get bids and go with lowest bid to save money on HVAC most of the companies goin for strip mall work just throw units on and ductwork in and then another company come and has to fix the install happens a lot here in Delaware too

I've currently been approved to replace the LightStat at this retailer but I'm not yet sure about the rest. Since the place has only been open since the first week of last November, I'm hoping the owners will force the installing contractors to make the other repairs.
I'm pretty sure the work was permit required and may have been inspected but from what I've learned about inspectors in SC, if they see a unit where it's supposed to be by the drawings, it passes.
I've been stuck on jobs like this more times than I can remember, I get to fix all the screwups that the slack-hack installers put in in a "smash and grab" manner.
I'm often surprised that the sparkies and hacks will take the time and trouble to drill holes in the worst possible location to pull wire through but won't bother to use a bit of seal-tite or connectors to keep rain from entering the building through the units I'm now responsible to maintain and repair.
I'll get more info Monday morning when I get to the jobsite.

is the flex and tstat wiring run through a hole he took the time to drill out? surely he would have just went through the knockout?!

Lazy and no pride in workmanship.... If they cut corners on romex connectors or flex and fittings .... Doubt the duct work looks any better...

Good luck there Will....


I hate light-stats...

That is a real shame, hard to believe people actually get away with this. This work was obviously not permitted and inspected. I would be a little concerned about the owner of the building, does he handle business in the same way ? It does create work for the rest of us though.

The RCB's Cousin Doofus has returned!

Get an emergency call for no heat in the building. I get there, check the thermostats, all are calling for two stages of heating. I go up on the rooftop and start checking. First off this retailer has only been open since November 8, 2007 so, everything is relatively new. I didn't expect what I found.

All four of these units are CARRIER 50TM006A501.
The LV wires to bring on the heat strips were attached to the wrong terminals in the strip kits, the transformers were set on the 230 volt terminal with the unit receiving 208, the thermostats were wired with one wire on the "O" terminal but these units are electric/electric, not heat pumps.
Got all that fixed and found more. All four units are setup like these photos, I can't wait to get the corporate owner involved.





Only three of the four have this little problem. Well, it's not a problem just yet but, how long do yo think that duct tape patch is gonna last? That was the knockout for the internally mounted service disconnect but, Cousin Doofus didn't know what to do so, he just took it out of three of the units.



I found one of the units operating in heat and cool at the same time but, the thermostat was only calling for 2 stages of heat. Did some deep checking of wires, conduit, diagrams, unit wiring, unit components and lastly, the thermostat. I found where an incorrectly lan'ed wire had arced and that did the thermostat in. This orange wire was tied to the "O" terminal of the LightStat but, it was just hanging there rubbing up against the cabinet in the RTU.





All of the thermostats are LightStats, I called tech support and found that this sort of failure is most definitely not covered under the LightStat warranty, I guess someone is going to buy a new LightStat.

I've said it before, I like job security but this is ridiculous!