DDR SETTING

[NANOTECH]

OK started up a LT R404A Tyler/Envirogard today. Rack has four compressors hot has defrost with a Parker DDR valve. Is the DDR valve energized or denergized when circuit in defrost? Should condenser fans be on or off when adjusting valve? How many compressors should be running when setting valve? There is a tap on the discharge inverted trap and a transducer on the discharge header. While in defrost what differental pressure should I be looking for between these two points and under what conditions?

[crackertech]

OK started up a LT R404A Tyler/Envirogard today. Rack has four compressors hot has defrost with a Parker DDR valve. Is the DDR valve energized or denergized when circuit in defrost? Should condenser fans be on or off when adjusting valve? How many compressors should be running when setting valve? There is a tap on the discharge inverted trap and a transducer on the discharge header. While in defrost what differental pressure should I be looking for between these two points and under what conditions?

The DDR is denergized during defrost.To adjust the valve I bypass (note nothing is in defrost just override the valve) into defrost and adjust to 15-20 psi diff.

[crackertech]

BTW ya got enough post to apply for pro.Go for it you wont be sorry lot's of great info to be had in the EF.:D

[NANOTECH]

What do you mean override the valve? Nothing should be in defrost when looking for the 15 to 20 diff.? Should this valve be all the way open when not in defrost? ( no differential)?

[crackertech]

What do you mean override the valve? Nothing should be in defrost when looking for the 15 to 20 diff.? Should this valve be all the way open when not in defrost? ( no differential)?

No denergize the valve( ie )move the dip switch on the ro board with nothing in defrost and set to 15-20 psi diff.

[NANOTECH]

OK, lets make sure that I didn't sniff to much phosgene gas today HEHE! Regardless of how many condenser fans are running or how many compressors are running and no systems in defrost. All I have to do is denergize the DDR valve and at that point set the diff. press. across the valve between 15 to 20 psig?

[crackertech]

OK, lets make sure that I didn't sniff to much phosgene gas today HEHE! Regardless of how many condenser fans are running or how many compressors are running and no systems in defrost. All I have to do is denergize the DDR valve and at that point set the diff. press. across the valve between 15 to 20 psig?

Yep ya got it. And just remember LODR'S are engerized during defrost.Just food for thought.:D

[NANOTECH]

Thank you very much crackertech!!!!!!! Homerunn!!!!!!!!!! After all these years you think I would have that down! Still get confused sometimes between all the A8, A9 DDR, OLDR, LDR, Master line solenoid Check valve. Just ran across one of those there smart valves the other day! Had to have a palm that works off of infared to set the valve valve up! Controls board mounts up under the return air. Got to point the palm through the return air grill on the case to set all the parameters! Fancy stuff!!

[crackertech]

Thank you very much crackertech!!!!!!! Homerunn!!!!!!!!!! After all these years you think I would have that down! Still get confused sometimes between all the A8, A9 DDR, OLDR, LDR, Master line solenoid Check valve. Just ran across one of those there smart valves the other day! Had to have a palm that works off of infared to set the valve valve up! Controls board mounts up under the return air. Got to point the palm through the return air grill on the case to set all the parameters! Fancy stuff!!
Yep we use sms(superheat management system) in a few markers it is fancy stuff but when it fails it sucks.If ya don't have back up parts.:eek2:

[NANOTECH]

This rack does not have a holdback valve on it. It has a valve pipped between the discharge line and the center of the reciever. Am I correct to assume that this is to maintain head pressure durring low ambient conditions? And if so what should it be set at?

[MikeySq]

Is this an enviroguard rack or NC2?

[NANOTECH]

Hey there Mickey! Its a Older Tyler Envirogard. The valve runs paraelell with reciever 90's over out of the center of the reciever 90's to the right into the valve goes down about 3' and 90's into the discharge line!

[NANOTECH]

OK since nobody is bighting on this, lets just say that it is a hot gas bypass valve with the purpose of keeping head pressure up durring low ambient conditions. Any sugestions on what the valve should be set at?

[MikeySq]

OK since nobody is bighting on this, lets just say that it is a hot gas bypass valve with the purpose of keeping head pressure up durring low ambient conditions. Any sugestions on what the valve should be set at?

Kinda sounds like NC2 maybe but i guess i gotta see it, Enviro guard typically does not have anything to bump up head pressure using discharge. Is there a Sporlan OLDR and a larger sporlan solenoud valve

Do you have a refrigerant level in the Reciever?

Does the reciever have a bleed line that runs from the reciever through a 3/8 line through a solenoid then a cap tube and a copper line wrapped around the main discharge header then to the suction?

Mike

[MikeySq]

don't see a enviroguard making much sense down in Virginia but NC2 would be a better for your climate,but thats a guess id say

[jpsmith1cm]

I find it hard to believe that this rack was built without a holdback valve. I've never seen a rack built that way.

As far as where to set that particular valve, this is how I set them.

Condenser fan cut out pressure for last fan = Lets say 145, just to assign it a number.

Holdback valve will then be set for 135.

Receiver valve will be set between 125.

Adjust your values accordingly.

As I said though, the valves work in concert with one another, so I can't see how one will work properly without the other.

[MikeySq]

I find it hard to believe that this rack was built without a holdback valve. I've never seen a rack built that way.

I've seen and worked on lots, it's a geographical thing depends on climate, I'm surprised you don't have them down your way? you're not that far south! haha

http://i492.photobucket.com/albums/rr289/MikeySQ/Enviroguard-2.jpg

[NANOTECH]

It has a Parker DDR there is no other valves not sure about the 3/8 line I will check it today and take some pics!

[NANOTECH]

I too could not believe there was no holdback valve! I am use to seeing the A8 and A9 working together. Thought maybe they were doing somthing I was not aware of. This is an old rack and has been in more than one store, someone may have cut the holdback valve out. Maybe I will install one and set it up the way you suggested--- Then I know what I got!!

[jpsmith1cm]

Mikey, I've heard of and about the enviroguards, just never seen one.

Biggest reason, I think, is because they aren't what everyone around here is 'used to' and they wouldn't ever run correctly because of that.

[MikeySq]

Biggest reason, I think, is because they aren't what everyone around here is 'used to' and they wouldn't ever run correctly because of that.

that happens here too, i went in to a 1.5 year old store that we took on after the warranty expired from the installer it about 20 buttons on the E2 and the suction capacity demand went from average 75% to about 33% average, so we have those service people here too. not to say that's an enviroguard issue but a service issue! haha