Actually, it could be a volumetrically compromised compresso

Marc O'Brien · Joined: 23 Jan 2008 Posts: 91

I poped back in to see how this cellar cooler system was doing after
my repairs.

It's iced again but this time the full charge still exists, subcool
remains sufficient.

It's design saturated evaporating temperature is about 4 deg C,
however, surely, due to an inefficient compressor the lower evaporator
circuit freezes?

http://www.fridgetech.com/miscellany/images/cellar_cooler.jpg

Archived from group: alt>hvac

geojr · Joined: 07 Aug 2007 Posts: 11

"ftwhd" wrote in message @4ax.com...
> On Thu, 21 Feb 2008 16:14:23 -0800 (PST), "Marc O'Brien"
> wrote:
>
>>I poped back in to see how this cellar cooler system was doing after
>>my repairs.
>>
>>It's iced again but this time the full charge still exists, subcool
>>remains sufficient.
>>
>>It's design saturated evaporating temperature is about 4 deg C,
>>however, surely, due to an inefficient compressor the lower evaporator
>>circuit freezes?
>>
>>http://www.fridgetech.com/miscellany/images/cellar_cooler.jpg
>
> I looked at the picture and it appears the txv sensing bulb is
> incorrectly located.
>
> Are those heater wires I see? Does this unit require a defrost cycle?
>
> Marc there is obviously a flow problem of some type (air or ref)
> causing the bottom to ice.
>
> My short list (related sub sets not included)) is, air flow short
> circuiting the evap because of missing parts, refrigerant circuit
> restriction, low air flow over the coil, non trapped condensate lines
> on low temp evaps (very remote) . Not necessarily in that order. Smile

>
Marc is the coil plugged with dirt, product being stacked improperly,unit
undersized or mismatched, tsat out of calibration, door seals bad, drain
plugged, defost clock bad, fan motor cycling on thermal or running backwords
(seen it) and what Mike said Smile

I could go on but..... Cavs pulled a big
trade today- getting desperate trying to catch your pistons Mike Sad

(

.p.jm · Joined: 07 Aug 2007 Posts: 527

On Thu, 21 Feb 2008 21:25:11 -0500, "geojr" wrote:

>
>"ftwhd" wrote in message
>@4ax.com...
>> On Thu, 21 Feb 2008 16:14:23 -0800 (PST), "Marc O'Brien"
>> wrote:
>>
>>>I poped back in to see how this cellar cooler system was doing after
>>>my repairs.
>>>
>>>It's iced again but this time the full charge still exists, subcool
>>>remains sufficient.
>>>
>>>It's design saturated evaporating temperature is about 4 deg C,
>>>however, surely, due to an inefficient compressor the lower evaporator
>>>circuit freezes?
>>>
>>>http://www.fridgetech.com/miscellany/images/cellar_cooler.jpg
>>
>> I looked at the picture and it appears the txv sensing bulb is
>> incorrectly located.
>>
>> Are those heater wires I see? Does this unit require a defrost cycle?

No, it has heaters but no defrost. Dufus.

>> Marc there is obviously a flow problem of some type (air or ref)
>> causing the bottom to ice.
>>
>> My short list (related sub sets not included)) is, air flow short
>> circuiting the evap because of missing parts, refrigerant circuit
>> restriction, low air flow over the coil, non trapped condensate lines
>> on low temp evaps (very remote) . Not necessarily in that order. Smile

>>
>Marc is the coil plugged with dirt, product being stacked improperly,unit
>undersized or mismatched, tsat out of calibration, door seals bad, drain
>plugged, defost clock bad, fan motor cycling on thermal or running backwords
>(seen it) and what Mike said Smile

I could go on but..... Cavs pulled a big
>trade today- getting desperate trying to catch your pistons Mike Sad

(
>

--
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B-Hate-Me · Joined: 07 Aug 2007 Posts: 36

"Marc O'Brien" wrote in message @s37g2000prg.googlegroups.com...
>I poped back in to see how this cellar cooler system was doing after
> my repairs.
>
> It's iced again but this time the full charge still exists, subcool
> remains sufficient.
>
> It's design saturated evaporating temperature is about 4 deg C,
> however, surely, due to an inefficient compressor the lower evaporator
> circuit freezes?

Add a hot gas bypass and solenoid.

Stormin Mormon · Joined: 07 Aug 2007 Posts: 284

Your Holiness: Nice of you to pope in on them. Did you grant absolution, and
let them kiss your ring?

Hey, I think you're a bit off, with your inefficient compressor diagnosis.
If the compressor wasn't doing, then you'd get not enough cooling. I'd be
thinking air flow through the evaporator. See if the fans are churning, one
blowing out, other one blowing in. Clean the evaporator with some alkaline
cleaner such as Alki-Foam, they often get dirty.

Your problem is too much cold power, and not enough heat transfer.

I popped in on some folks yesterday, but it wasn't refrigeration.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..

"Marc O'Brien" wrote in message @s37g2000prg.googlegroups.com...
I poped back in to see how this cellar cooler system was doing after
my repairs.

It's iced again but this time the full charge still exists, subcool
remains sufficient.

It's design saturated evaporating temperature is about 4 deg C,
however, surely, due to an inefficient compressor the lower evaporator
circuit freezes?

http://www.fridgetech.com/miscellany/images/cellar_cooler.jpg

Zyp · Joined: 22 Aug 2007 Posts: 275

Marc O'Brien wrote:
> I poped back in to see how this cellar cooler system was doing after
> my repairs.
>
> It's iced again but this time the full charge still exists, subcool
> remains sufficient.
>
> It's design saturated evaporating temperature is about 4 deg C,
> however, surely, due to an inefficient compressor the lower evaporator
> circuit freezes?
>
> http://www.fridgetech.com/miscellany/images/cellar_cooler.jpg

Marc;

This is a "cooler?" Are you depending on a normal 20 degree coil for a
cooler? What's the fixture temperature? Do you have random defrost or
planned defrost? How much traffic in the cooler [aspiration?] Just
curious.

--
Zyp

Marc O'Brien · Joined: 23 Jan 2008 Posts: 91

On Feb 22, 1:21 am, ftwhd wrote:
> On Thu, 21 Feb 2008 16:14:23 -0800 (PST), "Marc O'Brien"
>
> wrote:
> >I poped back in to see how this cellar cooler system was doing after
> >my repairs.
>
> >It's iced again but this time the full charge still exists, subcool
> >remains sufficient.
>
> >It's design saturated evaporating temperature is about 4 deg C,
> >however, surely, due to an inefficient compressor the lower evaporator
> >circuit freezes?
>
> >http://www.fridgetech.com/miscellany/images/cellar_cooler.jpg
>
> Isnt that the same pic you posted before? Got something recent?
> Is the problem still, the bottom passes icing? Ive seen that pattern
> before and thats why I mentioned what I did previously.

Indeed it is the same problem, Mike. The icing was just less this time
but not much less.

> BTW that evap looks like a hack job run to death. You didnt install
> or maintain that abortion did/do you?

It's not a bad installation. We didn't install it though.

> At any rate, Im surprised you are having a tough time with this.
> But then again, you took the time to take and post a pic and didnt
> take the time to look at the oblivious sight glass.

Lol, I'm not having a tough time Smile

Originally, at the time of the photo, the sight glass was going from
full to totally empty as the liquid column travelling down to the
indoor unit would bob up and down with the TEV hunting.

I merely unplugged the outdoor unit LP switch so that the fans would
continue to run whilst the unit thawed over the weekend.

This is a fairly large site with a quite a bit of kit and this one is
something noticed while on site for other reasons and again I popped
in, while on site for other reasons, to see if all was good after the
last works.

> Maybe you are over thinking a simple problem?

Mostly I'm using the system and its symptoms and measurements to train
an employee. I'm interested to see what other think of the matter even
though you of course have much less info than I have.

Marc O'Brien · Joined: 23 Jan 2008 Posts: 91

On Feb 22, 1:39 am, ftwhd wrote:
> On Thu, 21 Feb 2008 16:14:23 -0800 (PST), "Marc O'Brien"
>
> wrote:
> >I poped back in to see how this cellar cooler system was doing after
> >my repairs.
>
> >It's iced again but this time the full charge still exists, subcool
> >remains sufficient.
>
> >It's design saturated evaporating temperature is about 4 deg C,
> >however, surely, due to an inefficient compressor the lower evaporator
> >circuit freezes?
>
> >http://www.fridgetech.com/miscellany/images/cellar_cooler.jpg
>
> I looked at the picture and it appears the txv sensing bulb is
> incorrectly located.

I think the TEV bulb position and tightness is okay, there is good
thermal contact at 8 o'clock and the external equaliser is connected
after the bulb.

> Are those heater wires I see? Does this unit require a defrost cycle?

The heater wires are for winter operation, as Paul so eloquently put
it. If the cellar gets too far below set point then the heaters kick
in. Target temperature is about 8°C

> Marc there is obviously a flow problem of some type (air or ref)
> causing the bottom to ice.

I believe it is simply a refrigerant flow problem.

> My short list (related sub sets not included)) is, air flow short
> circuiting the evap because of missing parts, refrigerant circuit
> restriction, low air flow over the coil, non trapped condensate lines
> on low temp evaps (very remote) . Not necessarily in that order. Smile

The application is high temp beer cellar (8°C).

Marc O'Brien · Joined: 23 Jan 2008 Posts: 91

On Feb 22, 2:25 am, "geojr" wrote:
> "ftwhd" wrote in message
>
> @4ax.com...
>
>
>
> > On Thu, 21 Feb 2008 16:14:23 -0800 (PST), "Marc O'Brien"
> > wrote:
>
> >>I poped back in to see how this cellar cooler system was doing after
> >>my repairs.
>
> >>It's iced again but this time the full charge still exists, subcool
> >>remains sufficient.
>
> >>It's design saturated evaporating temperature is about 4 deg C,
> >>however, surely, due to an inefficient compressor the lower evaporator
> >>circuit freezes?
>
> >>http://www.fridgetech.com/miscellany/images/cellar_cooler.jpg
>
> > I looked at the picture and it appears the txv sensing bulb is
> > incorrectly located.
>
> > Are those heater wires I see? Does this unit require a defrost cycle?
>
> > Marc there is obviously a flow problem of some type (air or ref)
> > causing the bottom to ice.
>
> > My short list (related sub sets not included)) is, air flow short
> > circuiting the evap because of missing parts, refrigerant circuit
> > restriction, low air flow over the coil, non trapped condensate lines
> > on low temp evaps (very remote) . Not necessarily in that order. Smile

>
> Marc is the coil plugged with dirt, product being stacked improperly,unit
> undersized or mismatched, tsat out of calibration, door seals bad, drain
> plugged, defost clock bad, fan motor cycling on thermal or running backwords
> (seen it) and what Mike said Smile

I could go on but..... Cavs pulled a big
> trade today- getting desperate trying to catch your pistons Mike Sad

(- Hide quoted text -

I think the outdoor unit is possible slightly undersized in relation
to the indoor units to start with. Hence the poor distribution I
witnessed after the last works carried out on the unit.

Marc O'Brien · Joined: 23 Jan 2008 Posts: 91

On Feb 22, 11:01 am, "B-Hate-Me" wrote:
> "Marc O'Brien" wrote in message
>
> @s37g2000prg.googlegroups.com...
>
> >I poped back in to see how this cellar cooler system was doing after
> > my repairs.
>
> > It's iced again but this time the full charge still exists, subcool
> > remains sufficient.
>
> > It's design saturated evaporating temperature is about 4 deg C,
> > however, surely, due to an inefficient compressor the lower evaporator
> > circuit freezes?
>
> Add a hot gas bypass and solenoid.

Very inefficient and would require the installation of about 20m of
hotgas piping along a slightly awkward route. I don't think hotgas
injection is necessary.

Marc O'Brien · Joined: 23 Jan 2008 Posts: 91

On Feb 22, 5:24 pm, "Zyp" wrote:
> Marc O'Brien wrote:
> > I poped back in to see how this cellar cooler system was doing after
> > my repairs.
>
> > It's iced again but this time the full charge still exists, subcool
> > remains sufficient.
>
> > It's design saturated evaporating temperature is about 4 deg C,
> > however, surely, due to an inefficient compressor the lower evaporator
> > circuit freezes?
>
> >http://www.fridgetech.com/miscellany/images/cellar_cooler.jpg
>
> Marc;
>
> This is a "cooler?" Are you depending on a normal 20 degree coil for a
> cooler? What's the fixture temperature? Do you have random defrost or
> planned defrost? How much traffic in the cooler [aspiration?] Just
> curious.

Target room temperature is 8°C

Defrost is off-cycle. But, by design, should never be required anyhow.

Marc O'Brien · Joined: 23 Jan 2008 Posts: 91

On Feb 22, 12:14 am, "Marc O'Brien" wrote:
> I poped back in to see how this cellar cooler system was doing after
> my repairs.
>
> It's iced again but this time the full charge still exists, subcool
> remains sufficient.
>
> It's design saturated evaporating temperature is about 4 deg C,
> however, surely, due to an inefficient compressor the lower evaporator
> circuit freezes?
>
> http://www.fridgetech.com/miscellany/images/cellar_cooler.jpg

If the distributor and/or the 3 distributor tubes feeding the 3
parallel circuits are a little over sized then there will likely be
distribution discrepancies under normal design operation.

If the compressor has lost volumetric efficiency then head pressures
are lower. Liquid temperatures are lower. Both of these mean less
turbulence at the distributor. Less pressure drop across the orifice
and then too less flash gas means less turbulence. Then too the
compressor is drawing less mass out from the other side of the
evaporator exacerbating the already state of poor distributor
turbulence.

The result of the above is an amount of gravitational preference of
distribution. A little more tendency toward the sewer-flow path of
least resistance.

So then the bottom circuit tends to get more refrigerant mass. More
liquid than vapour. This means that the lower circuit might get too
much liquid causing liquid to even reach the TEV bulb. The TEV seeing
a lower superheat will tend to close down. The TEV closing down tends
to reduce saturated evaporating temperatures which means an increased
likelihood of freezing where there is liquid in the evaporator.

But then, in the photo, the equaliser line is iced. I didn't look to
see if this was the same this last time I popped in on the way past
the room. Maybe the TEV is leaking internally. Liquid is leaking into
the equalising chamber tending to over pressurise the bellows bottom
side cause the TEV to close and affect the poor distribution.

Marc O'Brien · Joined: 23 Jan 2008 Posts: 91

On Feb 23, 1:27 am, ftwhd wrote:
> On Fri, 22 Feb 2008 16:16:36 -0800 (PST), "Marc O'Brien"
>
>
>
>
>
> wrote:
> >On Feb 22, 1:21 am, ftwhd wrote:
> >> On Thu, 21 Feb 2008 16:14:23 -0800 (PST), "Marc O'Brien"
>
> >> wrote:
> >> >I poped back in to see how this cellar cooler system was doing after
> >> >my repairs.
>
> >> >It's iced again but this time the full charge still exists, subcool
> >> >remains sufficient.
>
> >> >It's design saturated evaporating temperature is about 4 deg C,
> >> >however, surely, due to an inefficient compressor the lower evaporator
> >> >circuit freezes?
>
> >> >http://www.fridgetech.com/miscellany/images/cellar_cooler.jpg
>
> >> Isnt that the same pic you posted before? Got something recent?
> >> Is the problem still, the bottom passes icing? Ive seen that pattern
> >> before and thats why I mentioned what I did previously.
>
> >Indeed it is the same problem, Mike. The icing was just less this time
> >but not much less.
>
> >> BTW that evap looks like a hack job run to death. You didnt install
> >> or maintain that abortion did/do you?
>
> >It's not a bad installation. We didn't install it though.
>
> >> At any rate, Im surprised you are having a tough time with this.
> >> But then again, you took the time to take and post a pic and didnt
> >> take the time to look at the oblivious sight glass.
>
> >Lol, I'm not having a tough time Smile

>
> >Originally, at the time of the photo, the sight glass was going from
> >full to totally empty as the liquid column travelling down to the
> >indoor unit would bob up and down with the TEV hunting.
>
> >I merely unplugged the outdoor unit LP switch so that the fans would
> >continue to run whilst the unit thawed over the weekend.
>
> >This is a fairly large site with a quite a bit of kit and this one is
> >something noticed while on site for other reasons and again I popped
> >in, while on site for other reasons, to see if all was good after the
> >last works.
>
> >> Maybe you are over thinking a simple problem?
>
> >Mostly I'm using the system and its symptoms and measurements to train
> >an employee.
>
> At what? How to handle a call back? Smile

Lol, I'm not sure what is your definition of a call-back so I can't
properly comment there but I appreciate the humour, you made me smile
on my break from the zeitgeist movie. By the way, books I have read
have told me everything so far half way through the movie already so
it is a little boring for me right now. The fact that one can be
absolutely sure religion is a load of bullshit is an old one and if it
wasn't for the crimes against morality committed by religious people I
just wouldn't care. But the problem is religious people are evil
people trying to be nice so hard they don't see the evil in their
ways. Their good intentions have the most evil consequences as always
happens when truth is abandoned in the name of good intentions.

But, anyway, back to the point at hand, one must always assume there
is more than one fault with a system and one must eliminate them one
at a time always making a thorough re-examination of the system after
each identified fault has been eliminated or cured.

Certainly a process of elimination of ambiguous symptoms and their
causes cannot be considered a process of "call-backs". Especially when
you have someone as smart as me on the case Smile

I eliminated two problems last time round, a leak and a short charge.
Thereafter the system was reported to have worked fine except that
when I popped my head in on my way past to another job I noticed the
icing of the lower circuit was recurring. I noticed refrigerant
distribution discrepancies last time round too.

I shall find the time in the near future to go in and take a closer
look. But the conversations exploring all the aspects from latent
heat, annular flow to temperature differences and temperature
gradients and tube heat flux to adp and shr and on and on have been
good a progressive just with the discussion of the possible causes of
these symptoms and what was found so far.

Tony · Joined: 07 Aug 2007 Posts: 41

Taken in consideration what stormin and zyp told you
I believe that EPR valve are still being made
tony

"B-Hate-Me" wrote in message @comcast.com...
>
> "Marc O'Brien" wrote in message
> @s37g2000prg.googlegroups.com...
>>I poped back in to see how this cellar cooler system was doing after
>> my repairs.
>>
>> It's iced again but this time the full charge still exists, subcool
>> remains sufficient.
>>
>> It's design saturated evaporating temperature is about 4 deg C,
>> however, surely, due to an inefficient compressor the lower evaporator
>> circuit freezes?
>
> Add a hot gas bypass and solenoid.
>

Zyp · Joined: 22 Aug 2007 Posts: 275

Tony wrote:
> Taken in consideration what stormin and zyp told you
> I believe that EPR valve are still being made
> tony
>
>
> "B-Hate-Me" wrote in message
> @comcast.com...
>>
>> "Marc O'Brien" wrote in message
>> @s37g2000prg.googlegroups.com...
>>> I poped back in to see how this cellar cooler system was doing after
>>> my repairs.
>>>
>>> It's iced again but this time the full charge still exists, subcool
>>> remains sufficient.
>>>
>>> It's design saturated evaporating temperature is about 4 deg C,
>>> however, surely, due to an inefficient compressor the lower
>>> evaporator circuit freezes?
>>
>> Add a hot gas bypass and solenoid.

For the first time in how many month's, I actually understood what Tony
said. An EPR valve might help here.

--
Zyp