First Cascade by Kamil_Grzbiecik

[Kamil Grzbiecik]

After a few Single Stage, it's time for Cascade.



Compressors - 1stg 18500Btu / 2stg 13000Btu
condenser - 3Kw + engine 35W embpapst
Heat exchanger[20]
Oil Separator - Temprite 340 + manual valve
safety - Pressure controls for both stages
Manometers - On the high side
Refrigerant - R507/1150(thanks Piotres)
Suction Line 100cm 54mm by Piotres
Expansion Valves - 1stg txv / 2stg Capillary 0.9mm 300cm
Basis - Wooden Rolling

Cascade was calibrated 315W load on the evaporator which forced -94 * C in idle circuit does -107 * C












Isolation, will still be improved.
That would be enough.


Kamil

[sdumper]

Did you use an expansion and desuper?

Very strong 1st stage compressor im envious!!

[Kamil Grzbiecik]

Expansion tank is gone and the 2stg desupu so that it does not.

[Patrickclouds]

i would think of buying a pipe bender.
pressure cut off switchs are not allowed to install with captube.
i suggest to use an exp tank. whats your static pressure? 30bar?
insulation looks a bit tapy
use normal pipe insulation and if you du it propper there is no need of using tape.
hope that is not final electric or will you put that unit into a case?

1m suction line is really short for mounting the suction line direct on the liquid sep of the rotary.
it's better to desuperheat the hot gas stream to get higher efficiency of oil seperation.

[n00b 0f l337]

I love the classic oil sep. I always liked a sight glass a few inches up though from it so I could see that it was capturing.
As for captube, make sure you are using a large bore captube or 1/8" tubing so that the cut off has a similar pressure to the system at all times.

Past that, awesome job.

[piotres]

pressure cut off switchs are not allowed to install with captube.

Why ???

[n00b 0f l337]

Because two situations can occur.
1) Captube gets clogged/blocked, HPCO does not trigger, ka-boom.
2) Pressure differential creates a lag in response (not big enough normally to be a real issue).

[sdumper]

Why ???

I would like to know what exactly hes talking about as well.

[n00b 0f l337]

Read my post Scott. It's an issue of clogging

[wdrzal]

Read my post Scott. It's an issue of clogging

The high pressure cut off should normally be connected to the high side (before the cap tube) where the pressure would increase in case of a blocked metering device.

Your reason NOL makes no sense. Neither does patricks statement that you don't use HPCO with cap tube.

You really can't make such general statements as each system needs to be looked at to determine what safetys are required.

It's just cap tube is the cheapest metering device and is usually used on single stage or simple systems(in design).

[n00b 0f l337]

You are missing my point. Not the systems captube. The reason not to connect a HCPO to a system with a capillary tube, is incase it gets clogged and therefore the HPCO never triggers.

[wdrzal]

You are missing my point. Not the systems captube. The reason not to connect a HCPO to a system with a capillary tube, is incase it gets clogged and therefore the HPCO never triggers.

None of my flaring tools makes flares smaller than 3/16" OD (1/8" ID) which is the smallest size most pressure switches use.

I don't think I even have a tool (or have seen or needed one) to do 1/8" OD flares. I'll have to look as I,m not completly sure.

Makes no sense to take a small diameter cap tube then braze it to 3/16" then make the flare.

[n00b 0f l337]

But again, we are talking about the example in this thread.

[sdumper]

The high pressure cut off should normally be connected to the high side (before the cap tube) where the pressure would increase in case of a blocked metering device.

Your reason NOL makes no sense. Neither does patricks statement that you don't use HPCO with cap tube.

You really can't make such general statements as each system needs to be looked at to determine what safetys are required.

It's just cap tube is the cheapest metering device and is usually used on single stage or simple systems(in design).

Thanks for the clarity Walt.

[mytekcontrols]

You guys are cracking me up

Nol got the point the first time around. To clarify...
When installing a high pressure compressor cut-out switch on a refrigeration system, it should be connected as close to the compressor's discharge as reasonably possible, and done so with a fairly good size piece of tubing (1/4" od is quite commonly recommended). The reasons are for what Nol already stated, non clogging, and for minimum delay in responding to a high pressure event. In Europe, it is mandatory that a cap tube not be used for this connection, as per their PED directive.

Sorry... I couldn't resist the urge to throw my 2 cents in. BTW, nice temperatures on the cascade.

[Patrickclouds]

there are havac standards that you have to follow. if not the technical inspection agency will not allow you to start running this unit.
i think that german standards are also european standards.

a blocking captube of the hp cut off switch will affect the functionality of the cut off switch.
and like NoL already said the lag of response can cause that the hp cut off switch won't do its job because a pipe has just exploded.

i don't make the rules, but i follow them.
it is also not alowed to braze on a pressure tank like piotres did in his builds.
i think you can find all informations in the havac regulations of your country.

[n00b 0f l337]

Bingo!

[sdumper]

You guys are cracking me up



Sorry... I couldn't resist the urge to throw my 2 cents in. BTW, nice temperatures on the cascade.

I aim to please

[Ian[Frozen]]

I'm a noob here and I thought there just had to be a severe miss-communication because I had extreme difficulty following the jist of the statement.. But now I get it, the missing link is: it's a bad idea to use a cap tube between the HPCO switch and the high pressure side of the system we're attempting to protect.. right??

[n00b 0f l337]

Yeap I thought it was pretty clear, sorry for the miscommunication.

[piotres]

Can You nottice that KP5 Danfoss cut-off in this cascade ? It's old (but never used before) cut-off and it have in box included steel captube to connect it to system - and it's used in this system like You can notice. So it's suggested way of connecting it by manufacturer ...

and approx 1.5 mm ID can clog ? I don't think so...

On another stage Kamil use new Johnsons Controls cut-off and he connect it with I think 0.9mm captube, that can be in fact too thin.

[Patrickclouds]

you cannnot compare components that are used before 15 years. standards can change in variations of time.

newer receivers are labeled with the EU policy of the max. permitted pressure. olders are not because there wasn´t an EU policy yet.

[sdumper]

I feel sorry for the original poster because everyone has completely hijacked his thread.