Prob. a bad sensor. It will trip on this if the entering water reads colder than the leaving water (on front panel). Another possibility is that your flow switch is closed but you really dont have flow.
the actual minimum pressure drop is 4.0 FEET OF WATER (about 1.73 psid) but i think that the REAL minimum is closer to 3-4 psid...sometimes i think trane allows the marketing department into the engineering department too much.
Your right it is "ft of water" not psid. Not the first time if spoken without thinking first.
Lets think about compressor loading (or unloading).If something is not operating right with the slide valve and keeping it from completely unloading that could give a sudden temp drop in the water at SU. On the other hand a leak in the loading circuit may allow the compressor to load on SU as the HP rises. Check amp draw, pressures at SU ?
I hooked up my first pressure gauge on the inlet side of the evaporator today and found that I had low pressure TO the evaporator from the water pump! I changed to the back-up water pump and now I have 20 PSI at the entrance and barely 1 PSI at the exit.
I looked at the chart in the book and found that we are running a higher GPM pump than what we need, but knowing that the delta P should be acceptable.
It still wonder about the internal design of the evaporator. It is strange that Circuit 1 would work, but not circuit 2.
Does anyone have a "cut-away" diagram of the evaporator that they could post?
I appreciate all of the input. Hopefully this is the end of the problem and there aren't any issues in the next day or two.
Has this evaporater ever seen "hot water " temps over 125degrees F will deform the plastic baffles and the heat transfer goes for a S?&$ and your evap temps will take a dive .
The 64 roars to life Whoo hoo ...shes a rolling chassis .
You bend em" I"ll mend em" !!!!!!!
I"m not a service tech.. I"m a thermodynamic transfer analyst & strategic system sustainability specialist
Best Austin Healey In Show twice in 2013 .....All those hrs paid off .
Longtime lurker here; sds, I see in your first statement you mention automotive plant. Is this chiller on an open sump? Is there an open tank somewhere in the chilled water system, or any other way for process debris or material to get in the chill water? If so, the chiller barrel could be acting as a strainer and be clogged up with that material. This would affect water flow rate and heat transfer. Flow decreases and pressure drop increases ( think of shutting a valve ). Heat transfer decreases due to insulating effect of material on tubes and maybe even covering some tubes and preventing water from flowing over them. This could also happen if there have been recent additions or repairs made to chill water system and debris was introduced ( this is less likely to cause this much of a problem ). If this is not an open sump.... never mind . I would look at Graham's last post. I have never seen that , but from previous posts I wonder Graham has?
20# entering pressure sounds low to me. Where are your pumps located in relation to the chiller? How many floors is the building? Have you checked the water makeup to make sure it's working? Did you use the same pressure gauge for the entering and leaving pressure readings?
I open my trane evaporator and metal baffles are both European and American (ertab, ertwb, RTAA)
Read page 120 of the IOM it clearly states that the evaporator is constructed using steel. copper and POLYPROPYLENE components .
Last time I checked polypropylene was a plastic unless I was absent from science class that day ????
The 64 roars to life Whoo hoo ...shes a rolling chassis .
You bend em" I"ll mend em" !!!!!!!
I"m not a service tech.. I"m a thermodynamic transfer analyst & strategic system sustainability specialist
Best Austin Healey In Show twice in 2013 .....All those hrs paid off .
Reply With Quote
Originally Posted by jayguy
Subscribe to this feed
