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Hope you are well too! yes it was a good thread! Im rarely so talkative on here all the best stan

Gentleman,I love this post and Stan while it's been a few years. I hope all is well with you and your family. Awesome display of collaborative efforts and truly sound diagnostic procedures. Just awesome....

Sorry forgot to post a update. We went ahead and replaced the slide valves in both units and the load unload solenoids and actuators and all is well. She has been running like a top since the repairs were performed.

now you have some recommendations on how to control it, good luck stan

Unfortunately the BAS system in this building still has a taradactyl that flies from the server room to the chiller to hit start and stop. I'm in the process of getting a bid together to update to a brand new BAS system.

hi Jay, yes of course , but thats the whole "proper commissioning" thing , i`d say you have to have the run status signals to bms, maybe 1 hr registered run time , controls enable standby ckt. Local chiller controls will stage this ckt as normal if rqu`d. And if alarm signal sent , instantly enable other ckt , Its good to have extra capacity of course, but has to setup correctly , eg chiller cycling the unloaders to death , stan

Originally Posted by stanbyyourword

Hi guys where as I would almost certainly always agree and follow you trane vets to a Tee , I stand with disabling stand-by circuit and alternating monthly on building controls , with same recommendation of capacity/current limit set way down say 60% as a start. Remember the key * this equipment is so oversized its still short cycling in summer load months, unless theres valve control piping issues , which for now we can assume there isnt. Its still two chillers in a way , (even though I do understand the characteristics that make them common),and I would treat them as such, and enable the standby circuit as needed in case of under capacity, same as you would a completely redundant stand-by chiller, The bad part is he says his controls are very old , who knows how versatile , regards stan

i understand what you are talking about and it isn't a bad idea. the only problem that i have with it (other than the old BAS controls) is that if 1 circuit trips off-line (for whatever reason), you do not have a back up circuit ready to go. if you trust your BAS to react quickly and correctly, then you have a reasonable idea...i just don't trust BAS guys to understand how to react properly.

Hi guys where as I would almost certainly always agree and follow you trane vets to a Tee , I stand with disabling stand-by circuit and alternating monthly on building controls , with same recommendation of capacity/current limit set way down say 60% as a start. Remember the key * this equipment is so oversized its still short cycling in summer load months, unless theres valve control piping issues , which for now we can assume there isnt. Its still two chillers in a way , (even though I do understand the characteristics that make them common),and I would treat them as such, and enable the standby circuit as needed in case of under capacity, same as you would a completely redundant stand-by chiller, The bad part is he says his controls are very old , who knows how versatile , regards stan

I agree with Jayguy. Also, you can set your "differential to start" setpoint up high to prevent short cycling.

I'm also very sorry to hear about your baby.

i would not recommend 'disabling' any circuit for an oversized condition. i do agree with current limiting the chiller during the low load times of the year to give the chiller a chance to have some run time without excessive cycling. this can be done by the BAS and it can be done manually.

unfortunately, the current limit is for the chiller %RLA instead of the individual circuits/compressors, however, it may still help.

i hope all goes well with your wife. talk about it A LOT with her. our 3rd pregnancy was a very early miscarriage...like 2 weeks into the pregnancy...we didn't talk about it much because it was an 'accident' and we didn't plan on it and we never had any other children...i did not think it was a big deal...WRONG! good luck!

main run as 100% got it

Originally Posted by stanbyyourword

Hi "main run." ? as to the individual circuit remote contacts , I just read diagram and yes they are available , so you could have ems guys program to alternate ckts for even runs , stan

This

Hi "main run." ? as to the individual circuit remote contacts , I just read diagram and yes they are available , so you could have ems guys program to alternate ckts for even runs , stan

Originally Posted by stanbyyourword

any of the Trane gurus know if there are remote contacts on chiller per a/b ckts to remotely enable? or just the main run? stan

I gather if you have Tracer it can communicate this digitally?

I think you are correct on the first statementas far as enabling a certain circuit not just a main run.

The UCM just has the main start stop input. It takes control of Circuit A and B from there. That is food for thought for sure to try once it's back up working the way she needs to be

any of the Trane gurus know if there are remote contacts on chiller per a/b ckts to remotely enable? or just the main run? stan

I gather if you have Tracer it can communicate this digitally?

ahh ok, may follow my advice still , disable one ckt and put some limit start w 60% on the running one , be much better for the machine longer runs , less starts , you should still have alarms to ems in which case it faults stan

This unit does several buildings and has a ancient EMS system on the complex. Usually this time of year it's off more than it's on even during the day. But early in the morning around 4 everything starts coming out of night setback to get rooms down to temp and that's usually when it trips. Even then at full load it runs about 15-20 minutes and shuts off.

Todays better than it has been since wednesday when we found out. The wife is definitely in better spirits.

if the chiller is short cycling so much ,due to low load / gross oversize, you need to disable one circuit, and probably have a monthly schedule to change between them, This is a school right? Im almost positive RTAA has "current limit " parameter that will allow you to say keep at 50-60% for longer run cycles, the question I have is why are they even running all night long and so early? Im very sorry to hear about your baby , that cant be easy compiled with a stressful job, stan

Thanks for the input. My customer ok'd slide valve rebuild and parts are on order. As soon as it's done I will let everyone know but I'm positive it will be good to go afterwards. I apologize for not getting back with anyone earlier the holidays were kinda hectic.

In the middle of all of that we went for our first sonogram last week to see our new little one at ten weeks of progress along only to find out we'd be having a miscarriage instead.

Thanks again. jayguy graham r123 and all of the others who have donated ideas and time to helping me get to the bottom of this.