Yup, it is the conduction of heat reason for using them. And yes, nylon is most common. They will get brittle when really old. Never had a problem getting them off. Worst case is having to double...
Type: Posts; User: Russ57
Yup, it is the conduction of heat reason for using them. And yes, nylon is most common. They will get brittle when really old. Never had a problem getting them off. Worst case is having to double...
Hard to comment given the lack of info but......
I'd suggest you have the BAS system stage off the chillers first at 4PM. Then shut the pumps down 10 minutes after the last chiller is staged off....
Thanks. Started new thread in pro's section.
This could get deep if you really want to understand ohm's law for AC circuits. Lots of mis-info.
For the original question best to think in terms of power (W) = volts (E) times current (I). If...
Probably easier to replace contactors than find out which one is bad. Problem could be electrical or mechanical in nature. I'd start by measuring current draw of each coil and then ohm values of...
Would imagine long ago original motor only had one cap lead and orange wire went to one side of cap. Then someone replaced the motor with one that has two cap leads and didn't know that the orange...
Most guys would be happy to have a lower approach. However I understand your desire to know why something has changed. The comment about transducer accuracy can't be overlooked so make darn sure...
Crab master I was hoping you would jump in. Did a search on the forum and you seem most likely to be able to help.
I only jumped out the digital input for the CT (fan status). I did so because I...
Fan CT isn't the problem. Already put a jumper wire across that digital input. Vista confirms fan status as "on" now. Seems I am going to have to fool the DP input. Would imagine it is a 0-10VDC...
I have one small part, emergency room, of my hospital on a Vista system. The rest is Inet. I know Inet well but not Vista.
My problem is they did a construction project and they replaced exhaust...
In general.....depending on if it is AC or DC voltage:
Set meter to DC volts. Press hertz button until you get % in display. Read your PWM signal. If meter says 25% you would go to 25% stroke...
A few "rules" might have to be obeyed. Typically you want your cooling tower water to be a certain amount of degrees over your chill water. That depends on your chiller. Ten degrees is usually a...
Rules of thumb can equal bad practice. Many would assume a 3 phase, 480 motor operates at 480 volts referenced to ground.....but it doesn't:) Since you have one end of the megger on ground you need...
You might find the following link helpful.
http://www.biddlemegger.com/biddle/Lowdown-MC.pdf
It does get a little cloudy at times:)
There are certainly positive displacment pumps with pistons. Then you have centrifugal chillers that compress refrigerant with an impeller.
Your best bet will probably be a "shotgun" approach. Call up True (800-424-TRUE) and give them model and serial number. You will want to buy the start capacitor, overload, and start relay. Those...
Most walk in's have a "defrost termination and fan delay switch". This is mounted on the evaporator.
When you go into defrost mode this switch lets the defrost heaters remain energized until the...
Wait a second.....you mention something that we assume is a 115 volt home unit and next thing we know you are talking three phase. World of difference between something that is using a start cap and...
Well....if you are at zero, or below as you have stated, and it stays that way, haven't you proven the valves hold?
Funny how you can make a walk-in mantain temp with a tsat and still have a lot of things wrong. It is a little harder to do that with just a pressure control.
Do yourself a favor. Learn how to...
Yes, I am debating fighting it. But we have a great relationhip with the inspector and I'd like to keep it like that.
A switch in series with the "4" terminal and the loads is the quick and dirty...
I'm going to have to get up there and see what all I have. It turns out both evaporators are hard wired 208. Best I can remember, when I installed A419's in them, one had to be wired for 208 but...
No. The 120 volt one just plugs into a ceiling mounted receptacle. The 208 volt one is all hardwired.
Kinda looking to find out if NEMA 4X and/or low voltage is required.
My fire department inspector says we need a switch inside the walk in freezers to kill the evaporator fans in case someone gets trapped inside.
These are normal pump down type systems. One...
Shockwave, remember it is a "differential" switch so it isn't looking for just 60 psi. It is looking for 60 psi "difference" between suction and discharge side of the pump.
I'm going to bet the...
Bigtime, just all depends on conditions (temps/humdity/etc). You could get away with stuff in some parts of the country that would never fly in others.
These days I wouldn't even design with a...
You would always want primary flow to be larger than secondary flow. You can violate that for short periods but doing so for any degree of time will cause lots of problems with humidity and such.
Also.....lower voltage cause higher amperage "if" torque is required. In other words torque is proportional to square of voltage. Motors that are being started at reduced voltage are usually seeing...
I would be careful saying a run capacitor's main job is to correct power factor.
I'd rather say the capacitor shifts the phase of one of the windings so that the voltage across the winding is at...
Not only is the voltage rating higher on the FNQ series, the interupting current rating is WAY higher. If you don't know the importance of I.C. rating then best you make sure you always put the...
This is the Ask Our Pro's forum. In order to post a response here, you must have verified qualifications and have been approved by the AOP Committee. You may ask a question by starting a new thread....
Here are the pics for the old tube base Barber Coleman controls. This particular one isn't on-line anymore but I do have some that are.
As you can see I have quite a mix of different "vintages".
There is a reason why there are megger tests....and then they are hi-pot tests.
A megger test is supposed to be non-destructive. Every insulation class has a rating. We are supposed to be...
For normal electrical stuff there is little reason not to reference control voltages to ground. However there are a lot of valid reasons for floating neutrals and grounds. I work at a hospital and...
I love my old hand crank Biddle. If buying new today I'd go AEMC.
Match the megger to the voltage classes you work with. If you work on 4,160 motors you need a 5,000 VDC unit.
IMHO top uses...
Hmm, so now I'm a liar? Let me get through this hurricane and I'll see if I can figure out how to post a pic.
Pray tell, what is better about a 10mm?
A combination of PH, conductivity, and nitrate levels will give you an idea of how much you are leaking. Leave the regulator on. There is no such thing as too much water but you can certainly have...
Yes, I did mean an EPR valve. BTW, thanks for the education above. I don't normally work on stuff quite like this.
Cv equals GPM times (the square root of specific gravity of the fluid over the pressure drop across the valve). Perhaps an easier way is to say, "Cv is the number of gallons per minute, at 60...
I have to admit to not being sure what I should do. Too bad work isn't interested in me adding a CPR and check valve.
I think I'll put it back in service, order a TXV, and install it later on.
That ain't nuthin. My liebert has pnuematic controls. 1978 vintage IIRC. Runs like a top.
Now if you want a real laugh....I have AHU controls.....old barber-coleman....that run on vacuum...
Don't guess. Get the performance chart and see if the compressor is operating correctly. Not enough info is given to say for sure.
Hard and fast rules are what gets begineers in trouble.
It is easy to say "charge by SC with a TXV and charge by SH with an orifice". However such rules assume the TXV or orifice and working as...
What is the suction pressure on your chill water pump? Does the regulator have a part# on it? Why do you think it is letting too much water in?
Glad the B&G link helped. Chill water systems...
The frig section whichs setpoint just fine. Maybe I don't really have a problem? If I understand you right I'm basically running a -30 evap with 80 degrees of superheat. TXV body is very cold but...
Password??? Another of my pet peeves. Systems with factory default passwords that can't be changed that anyone can find out about.
When the control vendor comes to my site I want him to need me...
A CRO is piped on the outlet of the evap and a metering device would be piped on the inlet side of the evap (for quick check if not sure of what you have). In the pic it looks like you have a cap...
The separator is piped to the expansion tank. Better I give a link. Didn't want to write an essay. This should work.
http://completewatersystems.com/wp-content/uploads/2011/12/A-307A.pdf
This is why I ask you guys questions. Blows my mind to see a higher suction pressure with just the freezer running than just the frig running.
Still have to think the frig TXV is bad. It runs...
Okay, one chill water pump only???
If so you have variable pumping through the chiller. I would certainly cut off the bypass ports on the 3-way valves at the air handlers. Ideally there should...