defrost termination question from a sparky

[skotup]

im working on a new job where a defrost termination is to be used. I understand it is used to terminate the defrost cycle once about 50degreesC is reached? correct me if im wrong.

I remember from when i was a 1st year apprentice i was working on an instalation where a defrost termination was used. It was a pressure switch with equalising lines in parrallel with a suction soleniod. Does this type of system require a liquid line soleniod plus a suction solenoid operating independantly from each other? or does my bad memory from years ago when i was a 1st year misguide me? Ide like to know because the sparky running the job has run in cables for all known circuits yet i have a feeling we need one more circuit for this suction solenoid.

dont know if this helps you but this is current circuits allowed for on a freezer room...
Defrosts
soleniod
fans
anti-sweats
drain heater
controll(door switch+door light+iso relay)
temp probe(data)
fandelay probe(data)
defrost termination
heater safety

does a suct sol need to be added?

[thornguy]

The most common is a 3 wire DTFD, (defrost termination fan delay) switch.
You will have a common, a close on rise, and a close on fall in this switch.
Most common termination is 55°F and fan delay is 20°.
A suction stop is commonly only needed on a rack system with multiple evaporators.

Typical operation:
Timer calls for defrost, switching from the fan/solenoid circuit to the heater or hot gas circuit. The fans de-energize as well as the pump down solenoid. The heaters or hot gas is initiated.
When 55°F is achieved, DTFD closes on rise and sends the timer back into refrigeration. When coil temp reaches 20°F, the fans come back on and you are back to refrigeration.

[luskys a/c]

Not too long ago I was working on a 3-door TRUE rack unit and it was only 4years old but the owner just bought this piece of equipment among others at a SAMs club sale. The unit was a Freezer and it would only pull down to 60*f .I found a leaking Service valve and repaired but before the fans took 20min to come on and it puzzled me at first until I looked at the wire schem. There was the (DTS) and until the coil temp was met the fans would not come on. Good lesson for me;)

[MikeySq]

dont know if this helps you but this is current circuits allowed for on a freezer room...
Defrosts
soleniod
fans
anti-sweats
drain heater
controll(door switch+door light+iso relay)
temp probe(data)
fandelay probe(data)
defrost termination
heater safety


when I wire a freezer in the conduit to the Evap(220V) I run 7 wires:

black Line 1(L1 on Timer)
black Line 2(N on Timer)
white Neutral (for light, anti sweat and 115V drain heat trace, if equiped)
blue Fans(4 On timer)
red Heater(3 on Timer)
yellow Termination(X on Timer)
black 16AWG, LL Solenoid( line from Electronic Temperrture control mounted outside box)

I allways use 12AWG, unless it's a larger evap which has bigger hearers use 10AWG wire, the Solenoid wire i sometimes use 16AWH where it has no big load

[fridg]

Are you licensed in refrigeration or hvac ? :confused:
or are you a licensed sparky doing refrigeration work ?



This sort of thing happens when you think you can earn some good bucks on the side , Plumbers and Electricians or Diy , pinching our very specialized trade when they have no , or very little background or professional training in this industry.

[skotup]

Are you licensed in refrigeration or hvac ? :confused:
or are you a licensed sparky doing refrigeration work ?



This sort of thing happens when you think you can earn some good bucks on the side , Plumbers and Electricians or Diy , pinching our very specialized trade when they have no , or very little background or professional training in this industry.

Its a sub-contract to the refrigeration company. New supermarket with an unusaul controll system thats not often used called carrel. Besides i reckon i could do nearly all the frigy work, i can braise and have the concerntration power strong enough to recognise the big pipe and the little pipe, what else do i need? lol Frigy's arent allowed to do sparky work in aus, too dangerous to the public once its up and running.

MikeySq; those wire colours are illegal in australia, you scare me; black active's and white neutrals!!?? some1's gonna get killed!!... unless you're in america with a pussy 110V, whats the worst that can happen? But blue fan and red anti-sweat is often used tho.

[markettech]

im working on a new job where a defrost termination is to be used. I understand it is used to terminate the defrost cycle once about 50degreesC is reached? correct me if im wrong.

I remember from when i was a 1st year apprentice i was working on an instalation where a defrost termination was used. It was a pressure switch with equalising lines in parrallel with a suction soleniod. Does this type of system require a liquid line soleniod plus a suction solenoid operating independantly from each other? or does my bad memory from years ago when i was a 1st year misguide me? Ide like to know because the sparky running the job has run in cables for all known circuits yet i have a feeling we need one more circuit for this suction solenoid.

dont know if this helps you but this is current circuits allowed for on a freezer room...
Defrosts
soleniod
fans
anti-sweats
drain heater
controll(door switch+door light+iso relay)
temp probe(data)
fandelay probe(data)
defrost termination
heater safety

does a suct sol need to be added?

If this is hot gas defrost on a parallel rack - you better have SOME sort of suction stop (SORIT, Reversing valve, etc) or you'll cook the compressors.

On electric defrost, as a general rule, liquid line solenoid de-energizes during defrost.

There are certain systems that do require a suction stop solenoid for defrost (service cases) and spell this out fairly well in the installation manual.

There is a store I service that was installed with suction stop solenoids for defrost and it is a major PITA.:mad: Receiver levels fluctuate wildly depending upon which/how many circuits are in defrost.

[skotup]

If this is hot gas defrost on a parallel rack - you better have SOME sort of suction stop (SORIT, Reversing valve, etc) or you'll cook the compressors.

On electric defrost, as a general rule, liquid line solenoid de-energizes during defrost.

There are certain systems that do require a suction stop solenoid for defrost (service cases) and spell this out fairly well in the installation manual.

There is a store I service that was installed with suction stop solenoids for defrost and it is a major PITA.:mad: Receiver levels fluctuate wildly depending upon which/how many circuits are in defrost.

Its not hot gas defrost, its electric heaters all programed to defrost at seperate times from one another.

[markettech]

Its not hot gas defrost, its electric heaters all programed to defrost at seperate times from one another.

1 means of controlling refrigerant flow is sufficient then;)

[skotup]

1 means of controlling refrigerant flow is sufficient then;)

I have seen a hot water defrost on an industrial instalation where amonia was used. When Defrost began soleniods on the hot water pipes opened up and water pumps started up. It was a chicken slaughter house where they used steam to de-feather the chickens. The massive evaperators had steam pouring out of them and the visibility in the room was like 20 meters (about 50 feet). Yer it was a big room with large forklifts loading and unloading constantly.

[kiwireeferman]

Its a sub-contract to the refrigeration company. New supermarket with an unusaul controll system thats not often used called carrel. Besides i reckon i could do nearly all the frigy work, i can braise and have the concerntration power strong enough to recognise the big pipe and the little pipe, what else do i need? lol Frigy's arent allowed to do sparky work in aus, too dangerous to the public once its up and running.

MikeySq; those wire colours are illegal in australia, you scare me; black active's and white neutrals!!?? some1's gonna get killed!!... unless you're in america with a pussy 110V, whats the worst that can happen? But blue fan and red anti-sweat is often used tho.

If it,s a Carel controller you require signal pair for room temperature probe, a signal pair for evaporator coil probe (defrost termination and fan start)
Live for fans
Live for heater(s)
common neutral
Room lighting
Trace heat for drain
Trace heat for door(s)
Trace heat for Equaliser port
Liquid line solenoid (for pump down if this is required)

[skotup]

If it,s a Carel controller you require signal pair for room temperature probe, a signal pair for evaporator coil probe (defrost termination and fan start)
Live for fans
Live for heater(s)
common neutral
Room lighting
Trace heat for drain
Trace heat for door(s)
Trace heat for Equaliser port
Liquid line solenoid (for pump down if this is required)


Oh is THAT all it is? danfoss has the same thing only its called a fan delay probe which bring me to another question, gonna make a new post tho.

[MikeySq]

MikeySq; those wire colours are illegal in australia, you scare me; black active's and white neutrals!!?? some1's gonna get killed!!... unless you're in america with a pussy 110V, whats the worst that can happen? But blue fan and red anti-sweat is often used tho.

I'm in canada and they're not illegal here and oops I forgot about the 8th wire a green ground but hey who counts the ground anyway hahaha it's allways there

and yeah Hots are usually Black and Red and Neutral for our pussy 110V electrical allways:p og BTW I'm In Canada


scared that blacks are hots?? hahah i guess there are other differences between north america and australia other than the direction that the tiolet water spins hahaha:p

[skotup]

I'm in canada and they're not illegal here and oops I forgot about the 8th wire a green ground but hey who counts the ground anyway hahaha it's allways there

and yeah Hots are usually Black and Red and Neutral for our pussy 110V electrical allways:p og BTW I'm In Canada


scared that blacks are hots?? hahah i guess there are other differences between north america and australia other than the direction that the tiolet water spins hahaha:p

OMG you use black active and red neutrals? what are your 3phase colors? we have red-white-blue as U,V,W phases.

[MikeySq]

Red is never Neutral in 120V system, three phase is commonly black red and blue, but sometimes i've seen black Red and White in three phase:p probabl;y not code tho

black is allways a 'hot' wire

what do you use black for?

[skotup]

Black is neutral, NEUTRAL-NEUTRAL-NEUTRAL!!!!

Where do you have 120V? i thought the international standard was 230V, 50hz except stubborn america with poor quality, non-durable paper money instead of plastic and 110V/60Hz.

[MikeySq]

Well I'm in Canada wich is right nest to the good ol USA so our Electrical systems are the same 120/1/60 is common 240/1/60 is common for higher amperage items, 240/3/60 and 600/3/60 are common in commercial and industrial applications

pardon my ignorance but here there is only a neutral in a 120V system, why do you call a black a Neutral in your 240/1/50 system?

In your 240/1/50 do you have a 240V leg and a Neutral(0V leg)?

Our 240/1/60 system has 2 120 V legs and no Neutral

120/1/60 is considered to bea saver foltage for common uses like everyday appliances and household use, would you agree to that, efficient isn't the issue safety is when comparing 120V vs 240V

-Mike

[skotup]

Well I'm in Canada wich is right nest to the good ol USA so our Electrical systems are the same 120/1/60 is common 240/1/60 is common for higher amperage items, 240/3/60 and 600/3/60 are common in commercial and industrial applications

pardon my ignorance but here there is only a neutral in a 120V system, why do you call a black a Neutral in your 240/1/50 system?

In your 240/1/50 do you have a 240V leg and a Neutral(0V leg)?

Our 240/1/60 system 2 120V and no Neutral

120/1/60 is considered to bea saver foltage for common uses like everyday appliances and household use, would you agree to that, efficient isn't the issue safety is when comparing 120V vs 240V

-Mike

ofcourse, lower voltage is obviosly safer, what do you mean by a 'leg' never heard that term. When you say 2 120V legs, is that 2 120V phases 180degrees apart from each other? You must have a good conductive soil for earth. We have a MEN (multiple earth neutral) system where the earth bar at the switch board is equipotentaly bonded to the neutral bar because our sand doesnt conduct verry well.