Headmaster condenser flooding (intermittent problem)
Having a little problem with a Liebert unit with remote condenser. Over the weekend there were a few alarms going off but the data room remains at temp. There were several "low suction alarms" as well as "short cycles". Both Low suctions were on circuit #1. I checked pressures and found seemingly low suction at first but then after watching it for awhile the sight glass cleared up and pressures seemed to be typical- around 60 and 225.(R22) It seems as though the other Liebert here runs at about the same. Shortly there after the pressures began to creep up 70 and 325psi- Comp#1 cut out on high head shortly there after. Now it seems as though it does circuit #1 does that almost consistantly. I checked the remote condenser and Im almost certain that the headmaster (sporlan OROAB-5-210) is stuck in bypass, explains high head. Thats the prompting story but my question is has anyone else experienced headmaster failure in both directions? I mean if the headmaster where defective and not bypassing the coil (im in Northern MN) obviously pressures will plummet creating a low suction condition- hence the alarm- but now it seems to have failed on the other end of the spectrum and is stuck in bypass creating a high head condition. Thoughts or similar experiances? Only one stage seems to keep up with temp demands but I was just wondering if intermittent headmaster failure "often" goes both ways. Thanks
Now about an hour after my original post it seems to be running just fine- 60-and 220psi. Weird
Dave- Check that pressure rateing R-22 should be 180 psi . R 402a,R404a,R507-210 psi
Actually that's what I as well as the local wholesaler thought also- that's what the OEM calls for (Liebert) and what the #s cross too. In fact there are 2 others all with the same headmasters, all at 210 with R22. Ahh yes... Lieberts.
Yes they can. I have experienced many that have done that. However, they have been (almost) all Alco. The diaphragm in the dome ruptures and refrigerant gets in there.
"Don't wish it were easier, wish you were better"
Any body dump a bunch of r-22 in it lately?
If someone dumped alot of 22 in to get the head pressure up in the low ambient condition, when the temp would rise the high pressure would cut out.
Check the receiver heater, if it is not working then the pressure will get too low in an off cycle, you'll get no refrigerant flow, and a low pressure alarm. Someone may have dumped 22 in to get the pressure up.
The headmaster may have failed but its not that common.
Nobody has added any gas recently Im the only one who takes care of this equipment. After I disabled comp/circuit 1 for awhile I ran it again to test the waters. It short cycled on the LPC as the head pressure slowly crept up- outside ambient was around 10*F give or take. This time I went up and shut the cond fans off (there are 2 fans 1 runs all the time,the other cycles on a OA stat) to speed things up. Eventually after short cycling on the LPC a few times the high side got up high enough to open the headmaster and push the liquid down- then the pressures seemed to have stabalized (I ran back up and turned the fans on) and that system then ran fine and the sight glass cleared up. Its a strange deal because like i was saying before the one time while I was wathching it, it was stuck in bypass and wasnt going through the condenser- I could feel it just by grabbing the pipes, and it cut out on high head a few times- then it turned around and takes forever to build up- like somethings not seating all the way inside the valve. If I were undercharged how could it cut out on high head like that (70/350 psi). I never thought about the receiver heater- thanks for the idea.
I had a similar experience recently, although it was the headmaster on a Manitowoc Quiet Cuber.
Another tech installed a new compressor, two weeks later I got sent out on it. The headmaster was stuck in bypass-450psi and tripping the HPCO. I replaced the headmaster and started it up.
Two weeks later, called back out. Headmaster stuck in bypass, tripping the HPCO again. They were warranty, so I couldn't cut them open. It's been running for about a month now with no issues.
It was just surreal having two fail like that in such a short period. Have you had any more issues with yours?
Its been about a week and I havent had any issues. Sorry about taking so long to respond to your question- havent been on in awhile. i did however have another problem that needed to be resolved with the same equipment that i posted some stuff about in comm HVAC. I ended up having to add some gas to the system to get it up to mfg recommended charge level (mid way on bottom receiver glass with the given ambient). Dont understand how I had to add charge when I recovered every last drop and had high pressure conditions before the repair (precedded by low pressure conditions). Strange. Long story longer-the new headmaster (OEM calls for 210 with R22) seems to have done the trick.
Originally Posted by TXFreeze
i used to take care of dozens of w/i w head masters , classic scenario on first cold day of year to stick closed, and pump unit down probably due to lubrication , raise the pressures a bit w rfgt or other , good to go regards stan
Keep it simple to keep it cool!
Liebert head pressure control...
I assume you're talking about a Liebert model LEE Temp receiver on the side of the condenser. It should have two sightglasses for assessing system charge. At 10 F you should see some refrigerant in the lower glass.
Verify the belly heater in that receiver is drawing amps. If not, find out why. It must work.
There should be a cold weather time delay in the controls which by-passes the LPC for about 3 minutes. That keeps the LPC from bouncing the compressor on/off on cold starts.
If you control head pressure with a head pressure valve that backs up refrigerant in the condenser then the 3 fans usually run non stop. Just try that.
I've bought a Testo digital guage that allows me to record weird situations that crap out when I'm not there. It might be worth getting one. You can plot pressures and temperatures, sweet.
with it being 10 degrees out, in addition the one condenser fan staying on, the head problem creeping up is telling me certainly she is stuck.
A headmaster is used to allow refrigerant to stack in the condenser to raise the pressure. Stacking "condensed" liquid fills the condenser making the effective surface area smaller for discharge gas to condense. Making the codenser small makes the head pressure go up. As it goes up to the predetermined setting, it will open to allow full past. Accomplished with a headmaster valve.
I say it to draw the obvious conclusion. The headmaster is not opening to allow flow on a pressure rise.
Can it due it intermittently? I have seen them fail like this intermittently. I have watched it plain as day. Work then not work.
I thought of non condensibles. But the thing is. Once air is in the highest point of the system, it stays there. It wouldn't be intermittent.