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View Full Version : Danfoss ORV (Oil Regulating Valves similar to the old Amot valves!)







Grizzly
30-07-2012, 06:42 PM
Hi Guys.
I rarely ever have cause to question any Danfoss kit.
However today, having discussed High oil temp issues which I am experiencing.
I phoned one of my colleagues from another region and he advised me that he knew of several sites where these have failed.
To the point where there use is being questioned.
Is anyone else having failures.
Grizzly

Nh34life
03-08-2012, 09:55 AM
Hey Griz, I have been experiencing more and more failures with Danfoss, not to mention supply in our end of the world. The tolerences have become "sloppy" since they have ot sourced there manufacuring to mexico and china i believe. The ORV piston either doesnt open or shut due to being stuck in the cylinder. I would recommend modulating water flow to oil cooler or solenoid on thermosyphon in cold climates rather than complexities of ORV or AMOT. I have always prefered danfoss for vave components but in recent years i tend to use the american "tank" Hansen

Grizzly
03-08-2012, 10:34 AM
Hi NH34life.
Thanks for the response, since posting it has become apparent that there is indeed an issue.
The formal answer is Danfoss are looking into it!
I agree with your comment about using Hanson as an alternative.
So long as they are not manufactured outside the USofA.
Them no longer being made in Denmark does seem to coincide with the failure rate increase.
Although no one will admit it.

Maybe I have "touched a nerve" as several guys have spoken about this with me off forum!

I will keep all posted.

To many accountants running the show if you ask me.
Grizzly

chemi-cool
03-08-2012, 01:02 PM
Danfoss are getting worse all the time. Had recently two TXV that lost charge after less then two months work and killed two compressors.
I use more Sporlan and Alco now.
It could be related to the fact that most of the parts comes from China.....

NoNickName
03-08-2012, 02:51 PM
On smaller SH compressors for R410a we had a recurring problem on internal NRV, which allow refrigerant back into the scrolls, and later seize by slugging. The range of SH where this occurs is exactly overlapping the range of compressors manufactured in China.

Grizzly
03-08-2012, 11:28 PM
Hi NoNickName.

You may have spotted a different trend there, however the need to add non return valves in the discharge line.
When using scrolls has been known for quite some time, in fairness no comp handles having large condensers directly above them.
As is the case with lots of modern chillers!
All the same thanks for the input and I will pay more attention of this kind of set-up in future.

Grizzly

engrp
04-08-2012, 12:22 AM
hi, have also experienced premature failures on some of our danfoss stop valves. but, aside from hansen, are there any other brand of ammonia stop valves of good quality ? before, grasso used to have "revalco" brand of stop valves. any observations on the new "stop valve" brand that grasso replaced for the "revalco"? if i am not mistaken, the new brand that grasso markets is "awp" .

Nh34life
04-08-2012, 01:49 AM
Have had good results with AWP. and I can get hold of them over night if i need them in a hurry. No other supplier provides this service.

engrp
04-08-2012, 07:25 AM
thanks for the comment, nh34life.

Tycho
04-08-2012, 09:31 PM
Hi Guys.
I rarely ever have cause to question any Danfoss kit.
However today, having discussed High oil temp issues which I am experiencing.
I phoned one of my colleagues from another region and he advised me that he knew of several sites where these have failed.
To the point where there use is being questioned.
Is anyone else having failures.
Grizzly

We have used these on close to 100 compressor packages, and I have only had 1 fail.
What happened was that the teflon strip separating hot from cold was leaking, and allowing hot oil to bypass the thermostat, causing high temp.
Replaced the teflon strip and it has worked just fine for 3 years now

Grizzly
04-08-2012, 11:20 PM
We have used these on close to 100 compressor packages, and I have only had 1 fail.
What happened was that the teflon strip separating hot from cold was leaking, and allowing hot oil to bypass the thermostat, causing high temp.
Replaced the teflon strip and it has worked just fine for 3 years now#

I don't doubt you Tyco.
There is not an issue with Quality from 3+ years ago!
Only this install is less than 1 year old.

A freezer plant with 2 comps on LT and 2 comps on HT.
1 comp on the LT side has already had it's ORV changed and this has failed again.
Same site only the chiller plant 2 comps on HT the lead machine is tripping on high oil temp due to the ORV having failed.
Another site within my area has 2 screw comps which is approx about 2 yrs old it has had 3 ORV's changed already.
As I said this has already been raised at the highest levels and is being investigated by Danfoss, I am assured!

I can only say it as I see it and do not like suggesting Danfoss have an issue.
As I have said I have always (Over Many Years) preferred Danfoss.

However they have an issue which is harming their reputation.

They are not alone in deciding to move their production to China.
Many others have done likewise!
But don't expect those of us that deal with the resultant products to just accept there is no alternative.
I just wish the alternatives were not so often made in America.
Grizzly

monkey spanners
04-08-2012, 11:34 PM
Have had a danfoss tev fail recently after install, first one ever. Notice the replacement ones are a new design, box has one of those 3D bar codes which takes you to a link about counterfit parts. Seems there have been a few fakes going round.

I've noticed that there are a lot of premature failures with chinese made parts (not just danfoss) i am trying to avoid them now but it is difficult as wholesalers only seem to stock cheap a$$ cr@p.

Nh34life
07-08-2012, 09:28 AM
I dont want to crap on china but its not just the quality has dropped but does anyone else notice the quality of steel is worse? i have worked on plants that are 40 years old which are just starting to fall apart, im am seeing more and more corrosion problems after 5 or so years

Teuria
22-08-2012, 04:29 PM
Hi Grizzly

I have changed those valves couple times because they didn`t work (gets stuck in random position). I suggest to you to change those first before doing anything else to the system.

Teuria
22-08-2012, 04:35 PM
I dont want to crap on china but its not just the quality has dropped but does anyone else notice the quality of steel is worse? i have worked on plants that are 40 years old which are just starting to fall apart, im am seeing more and more corrosion problems after 5 or so years

Don`t know that quality of steel but quality how valves are assembled. Couple weeks ago we installed couple of danfoss ICF valves to pump separator feed line and after couple of hours valve was leaking liquid NH3 from manual opening spindle, both of them. Hopefully Danfoss realize the problem before it`s too late.