York Recip Chiller LTHD

[iceman007]

I've had the most bizarre fault with a chiller running J series compressors. One of the 2 circuits is making a high pitched humming resonating sound. It only happens at loads below 70%. I have tried changing the condenser water temp, loading steps, and just about everything else. I've never seen a fault like this one ever. The compressor at 50% load hums quite noticably, then at 60% it's a little better. When the third head loads and the compressor loads to 70% it goes away. I also found out that there is a bit of history to this. The original compressor burned out and was replaced. When it was stripped at least one discharge valve was missing, and could not be found. So a new compressor was fitted, but because of the noise they had the original rebuilt and re-installed but the problem ws still there. I checked LP, HP, oil pressure (level was a little low but not too bad) and all is OK. All I can think of is that there must be a part of this valve in the condenser baffle or something from the first compressor. I am completely dumbfounded.....:confused:

[SCT]

Have you checked the loading sequence - meaning the correct solenoid coil goes to the correct head. (I only say this due to the compressor being rebuilt and they could be in the incorrect place)

[Magoo]

Sounds like a discharge stop/check humming at low flow rates, possibly a peice of the original discharge valve embedded in a seat, or a broken set spring in same valve, lower tension allowing seat to flutter hence humming noise.
Just thinking out loud. Magoo

[gregd1401]

Hi iceman007
Who did the compressor rebuild? Sounds like it may be a wave spring problem.

[iceman007]

Hi iceman007
Who did the compressor rebuild? Sounds like it may be a wave spring problem.

I was actually told that is was unadvisable to retrofit these compressors with wave type springs. Not sure why, but the same re-builder put in a new compressor, this was humming and then because of this changed it and re-fit the rebuilt original. I wonder if this is the cause ?

[airmate]

Hi,
I had a similar problem when i commisioned a reconditioned York chiller with J series compressor. we had bad pulsation issues as the chiller had remote condenser. What i found was that wrong cylinders were loading due to incorrect wiring of the capacity control and also had to programme the number of load steps i.e 5, 7, 10. Ensure that correct cylinders are loading and unloading according to capacity steps. To detrmine correct cylinders are loading refer to york manual for YCWJ or YCWR chillers. Hope this helps.

[iceman007]

Not sure if I have the manual, so I'll hav a look through my files. I do know that the panel is set for 10 steps of capacity, and also I know that the back cylinder, then the top and then the front (looking from the panel end) load in that sequence. Anyway, have to look at it further in the coming days..

[Grizzly]

Hi Iceman.
I think you already know that the only real way to resolve this one.
Given what you have told us.
Is to strip the Top End and check the valve assemblies.

You can fit wave spring assemblies to any J.
But you also need the relevant Valve carrier.
I have come across instances where the spring Valve combinations have been wrong.
Back cylinder is the permanently loaded one.

Assuming the customer will pay for it,
Stripping it will prove or disprove what myself and most of the guys are thinking.

Good Luck
Grizzly

[iceman007]

It's starting to look this way. I'vr got a scheduled Trane rebuild comig up next week for the same customer so we'll probably address it then. Thanks for all the replies, Grizzly in particular for the help and advice

[Grizzly]

Hi Guys.


You can fit wave spring assemblies to any J.
But you also need the relevant Valve carrier.


Strictly speaking the above comment is incorrect.
Because the earlier types of J operate at a lower oil pump pressure.
So to be correct wave Suction Spring assemblies can be used whenever the upgraded type of "Top Hat" Oil Pump has been fitted!
Sorry for the confusion.
Grizzly

[GHAZ]

The earlier type j bodies have a about 20-25 psi operating oil pressure,with oil pressure relief valve on the nde bearing housing, were as the js e and on wards have it on the drive end bearing housing, and the pumps are not changeable or the nde bearing housing

[iceman007]

Gents,

Many Thanks to you all. It turned out to be the driers splitting and the mesh was stuck in the liquid line all bent and twisted. All fixed and running.