Case of Chocolate biscuits to whoever can help me!!

[hookster]

http://www.islandbakery.co.uk/about/news.htm

This must be the most beautiful setting in the world for a bakery that I have ever witnessed.
Awesome use of the forum and feed back Joe, I am sure a lot of the people active on this post found it interesting and stimulating the old grey cells with your problem.

Your product looks good too (no melting chocolate)

[mad fridgie]

Hello!
Sorry for the silence. For various reasons we have only just been able to move the expansion valve. We've run it for a day since then, and we definitely have significant improvement. The TEV is now mounted directly below the distributor. Whereas before that section if the tunnel would go no lower than about 11c, it now reaches 8c.
It's still not running as well as unit 2 however...it will cycle on and off at 6c no problem, and will reach 1c if running constantly.
The gas pressure on the faulty unit is about 110psi. On unit 2 it's 160psi.
On the assumption that this could be caused by some kind of restriction, as a next step we're going to put in a new drier and remove the solenoid valve altogether. (It's not doing anything anyway; it's just wired in with the compressor and opens when the compressor runs.
Anyone got any better suggestions?

From what you have described,Gut feeling is that the modified unit is working far better than the other 2,
There maybe some other issues, but lets no worry yet. A simple test, turn off unit 2 and 3.
What is the result?

[r.bartlett]

From what you have described,Gut feeling is that the modified unit is working far better than the other 2,
There maybe some other issues, but lets no worry yet. A simple test, turn off unit 2 and 3.
What is the result?

You appear to be picking up the dialect?

[chemi-cool]

Hello!
and remove the solenoid valve altogether. (It's not doing anything anyway; it's just wired in with the compressor and opens when the compressor runs. .
Anyone got any better suggestions?

Yes, i got one suggestion, dont remove the SV, it cuts the liquid out when compressor stops to prevent from liquid runs into compressor sump.
Your compressors are under the evaporator , check also the compressor sump heater, it should run when compressor at rest.

[JoeReade]

if theres no temperature diff accross the drier then theres no point in changing it, as mark mentions check ur orifice size as undersized orifice will affect operating pressures and maybe use the solonoid as your control to pump down when at setpoint

OK - thanks guys. I'll get a new set of readings before we go any further. I'll check re crank case heaters too.
From the temperatures we measured previously, there did not seem to be a temperature drop across either the drier or the solenoid. Even so, we just thought that restriction could still be a possibility, and swapping the drier is not a big task.

If there is no temperature drop across the drier or solenoid, does that CATEGORICALLY mean there is no restriction there?

We have also changed the orifice from #2 to #3. We did try this previously before we moved the expansion valve, and the performance change seemed to be negligible. So the improvement we have achieved now is definitely due to the shorter distance between expansion valve and distributor.

I'll get a new set of readings posted soon. Hopefully later today.

Thanks again

Joe

[JoeReade]

http://www.islandbakery.co.uk/about/news.htm

This must be the most beautiful setting in the world for a bakery that I have ever witnessed.

It's not bad! But doesn't make a great deal of difference when you're inside baking....

[mad fridgie]

You appear to be picking up the dialect?

Och I
It coming back, spent a couple week on the isle of Mull (35years ago), climbed some hill, nipped across to Iona.
Loved the golf course! Stopped in the castle grounds.
Even though i was young, I did sneak a dram or 2

[marc5180]

If there is no temperature drop across the drier or solenoid, does that CATEGORICALLY mean there is no restriction there?

Ideally you should check for pressure drop across the drier or solenoid but more often that not, it isn't possible and so another way is to check for a temp difference across the part.
If it's 2C (2K) or more then the drier is blocked and needs replacing. If there's no temp difference then leave it as it is.

[nike123]

We have also changed the orifice from #2 to #3. We did try this previously before we moved the expansion valve, and the performance change seemed to be negligible. So the improvement we have achieved now is definitely due to the shorter distance between expansion valve and distributor.

In order to see if orifice change has influence we need some numbers.
First, TXV should be adjusted to factory position. Than orifice changed to No 3 and, when tunnel is near set temperature (1-2K), subcooling and superheat measuring should be done. Only after that we can go further with conclusions.
Maybe orifice need to be one size bigger, if superheat now is still to high.

[JoeReade]

Sorry for the delay... I think we have a minor gas leak, and so I want to make sure that is fixed before I take readings again. The engineer is on holiday right now...

[nike123]

Since you will be opening system for fixing a leak, then I suggest to change orifice to No 4 to see if with that orifice you will have floodback or not.