howden xrv compressors

[David Atkinson]

I have 4 x new ammonia chillers (400KW/600KW) that we have had a lot of teething/snagging issues on. 2 of these units are currently out of action due to ammonia leaks around shaft seals. I have heard rumours that howdens are prone to these with ammonia due to the use of carbon based seals.

Has any one had similar issues/problems or know of them?

[Grizzly]

I have 4 x new ammonia chillers (400KW/600KW) that we have had a lot of teething/snagging issues on. 2 of these units are currently out of action due to ammonia leaks around shaft seals. I have heard rumours that howdens are prone to these with ammonia due to the use of carbon based seals.

Has any one had similar issues/problems or know of them?

DAVID
It's possibly due to swarf or slag from the pipework installations.
Were Suction Socks used?
Howdens are usually very reliable and the carbon to steel faced s/seal is very common and reliable itself!

But they are susceptible to particulate contamination
within the oil.
Hence my suggestion.
It may be worth having the oil analysed?
Cheers Grizzly

[Plank!]

In my experience its not the carbon/steel seals that are the problem - its almost always the "O" ring material thats at fault.

I've lost count of the number of Howden shaft seals I've replaced due to the wrong "O" ring being supplied.
Once the mistake was realised the correct "O" rings were supplied straight away, still look a chump in front of the client when the third seal in as many months fails, but they did sort it out in the end.

Check that the material is compatible with oil and refrigerant together. Make sure Howden check it, not just send a standard seal

I've only once seal a howden shaft seal fail from another cause, that was a crack around the circumfrence of the carbon, probably due to being dropped during delivery.

Regards,
Plank!

[Grizzly]

In my experience its not the carbon/steel seals that are the problem - its almost always the "O" ring material thats at fault.

I've lost count of the number of Howden shaft seals I've replaced due to the wrong "O" ring being supplied.
Once the mistake was realised the correct "O" rings were supplied straight away, still look a chump in front of the client when the third seal in as many months fails, but they did sort it out in the end.

Check that the material is compatible with oil and refrigerant together. Make sure Howden check it, not just send a standard seal

I've only once seal a howden shaft seal fail from another cause, that was a crack around the circumfrence of the carbon, probably due to being dropped during delivery.

Regards,
Plank!

Hi Plank
A very good point you are making there.
One which I have also experienced.
May I ask has this happened to you on a Ammonia based plant.
I ask because I have yet to experience this type of failure on Ammonia.
BUT YOU DEFIANTLY MAY BE ON TO SOMETHING?
Frick s/seals leak like a sieve if the wrong one of 2 identical (looking) "o" rings is fitted.
Thanks Grizzly

[Josip]

Hi, David Atkinson

Howden is using John Crane shaft seals and they are good, but this was a problem....

.... its almost always the "O" ring material thats at fault.....

But this can be a cause...

It's possibly due to swarf or slag from the pipework installations.
Were Suction Socks used?
Howdens are usually very reliable and the carbon to steel faced s/seal is very common and reliable itself!

But they are susceptible to particulate contamination
within the oil.
Hence my suggestion.
It may be worth having the oil analysed?

.... maybe is not a bad idea to contact Howden and ask for some opinion/suggestion/answer...

Best regards, Josip

[US Iceman]

I ask because I have yet to experience this type of failure on Ammonia.

I have heard of this happening if the oil is switched from one type to another.

[Plank!]

Grizzly, This same problem has occoured 3 times now in 6 - 8 years, in all cases it was ammonia tho each time it was on a different site, one during commisioning, the others less than 1 or 2 years old.
I can't remember the exact details of the oil tho one i know was REFLO 68A and I'm certain atleast one of the other sites was on a fully synthetic oil.
Offhand i don't remember the "O" ring material that cured the problem, will try and find out next week when i'm back at work.

I think the solution here is to speak with Howden direct and not just let the office order the standard seal, I think most of us here know there is no such thing as a standard plant

[PaulZ]

Hi David
Plank is right about the type of O ring material, I had problems similar to yours several years ago and we found the O ring material was incorrect. If you Google O ring usage you might find a comparison chart. I have one but I am out of the office for a few days, if you can't find one let me know and I will post it when I am back.
Also if the replacement seal is not a genuine check the grade of carbon used, this can also cause a problem, from memory I think it's F35.
As Josip stated John Crane seals are usually very reliable.
Paul