Hot gas defrost

[adam5365]

Last year a local farmer bought lorry fridge body to store turkeys leading up to christmas.
some one came to "make it work" but butchered all electricals fitting a small control unit with control lines for compressor,evaporator coil fans and defrost.

1)The compressor contactor was wired directly from this external control bypassing the pressure switch and motor overload,I am currently rewiring reverting back to the 12v control system run from the new controller.
is it a good idea to re connect the pressure switch?

2) The hot gas system is all still "plumbed in" but not wired up as it has been butchered by another party, so
i have no idea how to rewire it.
are there any particular things regarding solanoid valve timing which one first, delay after change before compressor restarts?

Any help would be greatfully recieved

Sorry didnt realise i could edit post added more details in a new post (no 6)in this thread OOPS!!!
Adam



added 03/03/06

How very rude of me, I am most grateful for your help
especially djbe,referjohn and themo690.
djbe because he fully read and understood my post in that all circuit boards were smashed and so providing me with a full description of what connections i needed to make where, to get the unit up without the damaged control circuits.
referjohn and thermo690 because they took the time to find and send me the original wiring diagrams.
The unit worked for three days over Christmas without any probs although the defrost system is not yet sorted out.
During the summer wedding season the fridge will run almost continually so I will have to get around to setting up the defrost.
Please accept my apologies for my ignorance
Adam

[Brian_UK]

Connecting in the pressure and overload switches would be a GOOD idea as they will help protect the compressor from damage.

I'm not sure about the defrost solenoid valves as would need to see them or a sketch or photo to understand the layout.

[Latte]

Hi Adam5365,

I am assuming that it is the original reefer unit on the body and not something someone's added on after the body was taken off.

If so, give us the details of the unit and i am sure one of us will have a wiring diagram for it

Regards

Fatboy

[adam5365]

Thanks guys
Im back at the farm today will take some pics and do a sketch

[shanes696]

if you put in an elliwell cotroller with a hot gas defrost control facillity on it you should be able to wire everything back to the controller and barring a few minor adjustments to the paremeters, everything should be set up automatically to run properly.

[adam5365]

Guys
scuse me if I dont use the correct name for stuff and things but heres some info on the system

The unit is original, it is a Carrier Frigking zephyr 300. the pipes that lead to the engine compressor have been blanked off (3)in pic dc004,

what is, and how do i connect the ?at(1)in pic dc004,

I assume that (1)is the hot gas solanoid

pipe(4) is from the mains compressor

The fridge doc attatched is how the wiring stands at the moment, apart from a switch on the door to kill the evaporator fans and turn the inside light on that I fitted today.

the doc also contains layout of the pipes, not brill but I hope you understand it.
(1) compressor
(2)orange thing ((2)in dc004)
(3)hot gas solanoid ((1)in dc004)
(4)condensor
(5)evaporator

not shown on this layout( i forgot it )is a pressure switch tee'd into the pipe from ((2)in dc004) the orange thing to the condensor.

inside one of the electric bays there is a diag of relays on the cicuit board that was smashed, part of the diag shows a relay wired to reverse the mains three phase compressor ,why would this need to be done and do i need to set this circuit back up?

the controller that was fitted (badly)last year is an eliwell ID 974 data sheet at
http://www.invensyscontrolseurope.co...%206-03%20.pdf
Thanks again for you time
Adam

[evaporator]

Last year a local farmer bought lorry fridge body to store turkeys leading up to christmas.
some one came to "make it work" but butchered all electricals fitting a small control unit with control lines for compressor,evaporator coil fans and defrost.

1)The compressor contactor was wired directly from this external control bypassing the pressure switch and motor overload,I am currently rewiring reverting back to the 12v control system run from the new controller.
is it a good idea to re connect the pressure switch?

2) The hot gas system is all still "plumbed in" but not wired up as it has been butchered by another party, so
i have no idea how to rewire it.
are there any particular things regarding solanoid valve timing which one first, delay after change before compressor restarts?

Any help would be greatfully recieved

hi adam
all you need is a little controller an elliwell or similar.
you can then wire in your saftey switches to the controller and if you get one with defrost you can use your bypass valve, wire the controller as the switch live or ground to the pull in coils of the contactors for compressor/fans/defrost fit your sensors, set your parameters job done

[evaporator]

hi adam
all you need is a little controller an elliwell or similar.
you can then wire in your saftey switches to the controller and if you get one with defrost you can use your bypass valve, wire the controller as the switch live or ground to the pull in coils of the contactors for compressor/fans/defrost fit your sensors, set your parameters job done

sorry shane wrote reply before i see your post

[djbe]

Shane,

I think i've got some Zephyr 300 details kicking around somewhere. I'll check tommorow and let you know.

[phil68]

the id 974 should be ok for your purposes , i would forget all the previous wireing others have done , pull it out and start again , make sure you run the compressor through the contactor still and use the controll signal from the elliwell to controll the contactor as the contacts on the elliwell will probably not cope with the compressor amps and fail a lot quicker. the fans and defrost solenoid should be ok straight through the controller though.

hope this helps

[evaporator]

Zephyr 300 details kicking around somewhere. .

Hi Djbe
that was very well spotted from that photo, i have not seen one for over ten years

[djbe]

Sorry Adam,

I don't have a any Zephyr 300 details. The closest I have is Zephyr 200 but, to be honest these are photocopies of photocopies and unless you are clued up on Carrier equipment even originals are clear as mud

The only thing I can suggest is the same as Shane & Evaporator. Keep your ID974 controller and try the following:

1. Wire the disconnected safety pressure switch (the orange thing) in series with the compressor contactor switching feed.

2. Wire the hotgas solenoid coil to the defrost output of the controller. This solenoid should be 12 or 24v (I assume you still have the mains transformer in the system). Set the ID974 up for hotgas defrost. You will still need the probe in the evap. for termination.

3. If the evaporator fan relay is already switched by the ID974 this should stop when it the unit goes onto defrost (you may have to check and adjust the parameters if this does not happen).

4. Don't be afraid to rip all of the existing relays etc. out and start again if you have to, bear in mind that now the road operation of the unit has been removed it is very similar to a commercial refrigeration unit. The only real difference is the hotgas defrost and that the fans/control circuit will be 12/24dc.

regards,
djbe

[djbe]

Hi Djbe
that was very well spotted from that photo, i have not seen one for over ten years

Hi Evaporator,

I'm not that clever mate. I only know it's a Z300 because Adam mentioned in a previous post

[Reeferjon]

Can you confirm its a 400v 3 phase 12 or 24v system...if so email me off list.

John.

[thermo690]

Last year a local farmer bought lorry fridge body to store turkeys leading up to christmas.
some one came to "make it work" but butchered all electricals fitting a small control unit with control lines for compressor,evaporator coil fans and defrost.

1)The compressor contactor was wired directly from this external control bypassing the pressure switch and motor overload,I am currently rewiring reverting back to the 12v control system run from the new controller.
is it a good idea to re connect the pressure switch?

2) The hot gas system is all still "plumbed in" but not wired up as it has been butchered by another party, so
i have no idea how to rewire it.
are there any particular things regarding solanoid valve timing which one first, delay after change before compressor restarts?

Any help would be greatfully recieved

Sorry didnt realise i could edit post added more details in a new post (no 6)in this thread OOPS!!!
Adam

Hi please find attached the wiring diagram for this unit hope it helps

Martin

[Reeferjon]

Hey Adam...

Thanks for our help....glad you apreciated it

[shark26]

LoL ... perhaps he is stuck in reefer ....

[Reeferjon]

ramble:ramble:ramble

[adam5365]

How very rude of me, I am most grateful for your help
especially djbe,referjohn and themo690.
djbe because he fully read and understood my post in that all circuit boards were smashed and so providing me with a full description of what connections i needed to make where, to get the unit up without the damaged control circuits.
referjohn and thermo690 because they took the time to find and send me the original wiring diagrams.
The unit worked for three days over Christmas without any probs although the defrost system is not yet sorted out.
During the summer wedding season the fridge will run almost continually so I will have to get around to setting up the defrost.
Please accept my apologies for my ignorance
Adam

[Reeferjon]

Hey, Adam.
No Problem, glad to see you got the problem solved and customer happy.

John.

[yoelyeve]

Hello every one I'm having problems in supermarket with electric defrost the heater coils burn-out every 3 Mont's. so I want to convert the system to hot gas defrost
So if any one can help me out Please let me know