Disturbing headmaster problem..
I replaced a 1.5 HP R22 compressor for a keg cooler walk-in box this morning.Not thinking what could go wrong with filling the refrigerant,like any other day dumped some into the receiver,then started watching the moisture indicator and pressures and kept on charging.Was having a weird feeling about the glass when I got it to 200 PSI.At that point the internal relief valve opened in the brand new compressor.The high pressure switch tried to tell me but instead I blamed it and jumped it before this happened.
Had to wait and try to cool it (because the internal O/L opened too..) while thinking what the h**l is going on with my high side gauge.I determined it's not the gauge it's the headmaster (on the Russell unit) that's limiting the flow into the receiver.Soon as I saw my compressor was still okey and relief reset I turned the power off immidiately.(Too bad I didn't have a port or T connector on the discharge line..)
I cut the headmaster out,sure enough C to R side had crap in it.Tapped it onto something it's like dried mud that fell out.
Before the winter I will add a FCC to it.
The old compressor had mechanical failure.One of the two condensor fans was out (which I replaced it before starting the compressor.)Also evap was very dirty.I am too tired to get my notebook for model numbers right now,I don't think it's needed to enrich the story..
First time happening to me.I wonder if you guys see it once in a while too..
I've never run into one full of crap like that....yet.
I must admit though, even if the unit had a discharge service valve I'd probably connect to the liquid line valve anyway, just because it's usually closer and I'm less likely to get a new arm tatoo.
This is a good example of why, after giving the customer the diagnosis and repair estimate, it's necessary to CYA stating there may be other problems which become evident upon startup.
Very interesting....I certainly have never seen this scenario. But will certainly keep it in the back of my mind for future reference. I believe this would stump a tech if he is not fully understanding of how a headmaster works.
Originally Posted by wannafreeze
Just curious.....why opt for a fan cycle control and not just install a new headmaster?
Much cheaper and easier,don't have to recover on a rooftop,eliminate the possibility of this happening again.May have to replace the fans every few years.
Originally Posted by intellitech
I spoke with my old journeyman about this. Running into this before he stated "r 22 being parifin based broke down" in turn causing what you ran into.
Hope this helps.
I didn't give the back ground that adds insult to injury.This is a three story night club-restaurant that has just been renovated and a customer of mine and the landlord are going into this together.My customer is a lady who adores me (technically),made the whole town's restaurants my accounts.After working there 5 half days to check and fix all refrigeration there was one walking skipped,I didn't know about it and they didn't remember.Just before the final inspection day they let me know about it.When I went there to check it out at 5 pm,there were about 30 people walking around the place with her.I asked the cook who they were,he says "these are the people that are gonna be working here."
I found the compressor bad,told her I would do it the next day afternoon since I had doctors' oppointment at 11 am.She freaks out and says the inspector is gonna be there at 11 am and before that the kegs are gonna be delivered.They can't open for business if it's not running at 11 am tomorrow.So I decided I will take care of it by 10:30 am next day.
The next day I purchased the compressor,started the work at 8 am,replaced one fan motor,start components,CCH,blew out both coils,pulled vacuum down to 365 micron by 10 am and I was happy that I would make it to the oppointment.Actually if I missed this oppointment I would have to cancel another one with my physcian the following week.(The two cancellations already occured once last week!)
Do I have to explain my mood at 10:10 am?
I was done at 12:30.
She is paying for the whole thing..
Originally Posted by wannafreeze
Just another day in the life of a refrigeration tech......
Originally Posted by intellitech
Did I tell that when I was done she gave me a big hug when I was dirty and sweaty.
I was the MAN..
Last edited by wannafreeze; 05-23-2009 at 09:43 PM.
high discharge temps, breaking the oil down.
People who think they know everything are a great annoyance to those of us who do.
Last edited by sarpanch2001; 06-05-2009 at 02:16 PM.
Sorry to bring this back from the dead, but I had the almost exact same situation on a ColdZone walk-in-freezer R404a. I had diagnosed a weak compressor, wouldn't pump down below 25#. Customer never approved estimate to repair. 3 months later they call back, and I had almost forgotten about it until I'm looking at it, same compressor.
I asked the manager, "Didn't I condemn this compressor 3 months ago?" She said "yes, but our maintenance guy was able to fix it by adding more Freon. He's been out working on it several times but now he just can't get it to work anymore." Uhh, okk...
Well surprise! It still has a bad compressor. Customer approved our quote. So I get compressor and return to install it. I should have been more concerned about the black sightglass (not the moisture indicator; black as in the actual glass was black and you couldn't really see inside). I told her there may be other problems now that it's been running like this for months, so at least I mentioned it before I started.
Recover the charge, replace compressor, drier, sightglass, contactor. While charging, head pressure is climbing to 300# (its cool outside, maybe 50*F)... and headmaster is in full bypass.... Then HP switch is kicking off,, hmm thats strange, its set on like 425#, but my receiver is only at 300? ...maybe HP switch is miscalibrated? So I crank it up higher, and the little spring or lever or something broke on the HP switch..GREAT....
Tried to let it run some, but then compressor is going off on internal bypass.. WHOA something's seriously wrong here.
Obviously the headmaster, and now the HP switch is broken. Inform customer its going to be about $500 more than I estimated, they say OK. Recover charge again, replace headmaster and HP switch. I observed that the old headmaster had black goo in it! Evacuate, start charging up, thinking I fixed it now, but...SAME THING. Brand new headmaster is in full bypass at 350#...
So I recover the charge AGAIN!#$$#&~! Cut apart lines at inlet and outlet of condenser. Blew with Nitrogen, and 2-3 black balls of mud / debris came out. It wasn't gooey, but was hard like at had been cooked dry. So the debris was getting pushed into condenser inlet of headmaster and blocking it.
Brazed the new headmaster back in, brazed lines back together, pulled a vacuum, recharged. FINALLY it started working right.
I'm still happy I got that one fixed, but at the same time, kind of wish that day never happened! Spent probably 10-11 hrs on that one unit.
When you run into a problem like this you should install a filter drier on the discharge line just before the headmaster. This will prevent you from doing it all over a second time.