What do you know? The B6 sporlan valve has a 0.1875" port size. The Parker RB15E5 has a 0.562" port size. Guess it's that simple after all...

 

What is the length of run of liquid line?

Is there not a liquid receiver?

elevation of condenser to receiver to solenoid.

any riser of any kind?

any expansion devices?

trying to get a better idea of your layout.

can you do a sketch?

 

Liquid Hammer – Industrial solenoid valves, or other liquid line valves, may
cause liquid hammer when installed on liquid lines with high liquid velocities.

If this occurs, it can be minimized by the use of larger pipes, (i.e. lower velocities),
or a standpipe installed in the piping near the solenoid valve inlet. This is what you are referring to. When installing this think of the energy expansion. and piping flex. Are there any expansion joints in the pipe work?

Commercially available shock absorbers may also be used to reduce this noise. Recommended
maximum velocity is approximately 300 fpm.

What is the line size for this system. With design tonnage as well. If possible.?

 

I'll have to come back to this later with more details, but it's a very short run with less than 10' elevation total. Liquid line length is <20' of 5/8" ACR with no soft copper anywhere and no vibration eliminators. Compressors are hard-mounted to platforms on top of shell and tube condenser/receivers. No springs.

The compressor discharge is 1-5/8" and runs to a Temprite 926 oil separator and then to the water cooled condenser/receiver, total pipe length there is under 15'. Out of the receiver it runs through a dryer and then feeds the subcooling plate HX. Some liquid feeds a TXV here to cool the heat exchanger, the rest runs through the other side of the heat exchanger to be subcooled before running up roughly 3' to the liquid line solenoids for the main cooling circuits (there are two, cooling different plate HX that cool silicone oil). These heat exchangers are mounted 4' above the compressors, so the runs are quite short.

Tonnage is the part of this all where I only know enough to be dangerous. Here's what I know for sure: The "quiet" machine I've been working on since 2017 uses the same 30HP compressors as the loud one I'm working on today, but the quiet unit uses Danfoss 068U4319 TXVs with #2 orifices (068U4101) feeding the main heat exchangers, behind Sporlan B6 solenoid valves, which have 3/16" ports. If I read the paperwork correctly, the #2 orifice in this valve has a rating of 4.4 tons at a 4.4°C evaporating temp with 404.

The loud one is using those much larger Parker 0.562 port size solenoids and Alco TCLE TXVs but I can't get the cage size without taking them apart, so unfortunately I don't have tonnage ratings.

Aside from layout differences that make the piping roughly twice as long on the quiet unit and the different solenoid and metering valves mentioned above, the two machines are similar, but the quiet one in these two also has smaller liquid line. It's 1/2" out of the receiver, stepping down to 3/8" for the solenoid valves. Both use 2-1/8" suction lines from the main cooling HXs, run down to ground level from the HX outlet which is less than 10' up as mentioned before. Maybe a 20' suction line run on the longer/quieter unit. Roughly 10' on the loud one.

I'll try to make up a diagram soon.

Edit: Yeah today would have been a great time to take that TCLE valve apart and get the cage number, but this customer is ALWAYS in a big big rush. These machines are worth obscene money while they're running, so there's never any time.

 

When does this hammering occur ? At start up ... after running a while ...

 

Capacity tonnage of the entire unit is fine. Both stages.

Photos help a lot since we are not there.

Any log sheets, for data of inlet out let of process temperatures evaporator and condenser if available.

The data plate of the compressor.

Photos of pipe work mounting and run out of recover tank.

Operating condenser pressures and DSH, sub cooling temperatures.

Operating suction pressures and SST with SH if possible.

Also, vibration analysis. Has it been done once this unit was commissioned? The entire unit. Not just the compressor. I know sound strange. But on the first pipe fitting cracking and the problems your stating. I would try to out rule unnecessary vibrational stress from other sources.

 

a capped-off vertical pipe to give it a vapor cushion.

How does that work? How can you have vapor sitting on top of subcooled refrigerant? Wouldn't that only provide a cushion if the stub were filled with non-condensables?

 

What your describing, Correct not very effective in absorption of hydronic shock waves. It could absorb some shock waves. But the velocity aspect will still be adding to the mix.

Going to illiterate what I mean, as a stand pipe.

A change in direction of the pipe run vertically, with a larger pipe diameter. (Depending on space), to then return to the original pipeline run. A few ft before the solenoid valve. More like a inverted U. With a king valve at the top of the stand pipe for service access if needed. And measure pressure waves in liquid.

This does several things.

1- Lowers fluid velocity. Several changes in direction of flow.

2- allows pipe work expansion/ contraction.

The old water hammer plumbing trick, works for a bit. But eventually fills completely with water and loses it’s ability to absorb shock. Cheap, but not long lasting.

 

Right, I’m aware of the pipe stub full of air for water hammer. I know that they don’t work forever and you have to periodically drain the system to get air back in them. I was curious how that was even possible with a refrigerant system.

 

The idea of the vapor or charge staying at the top of just a pipe vertically erected. Will eventually fill with fluid and just be a hydraulic piston. With very slight movement of absorption.

So, no... Not cost effective. The size of the pipe would have to be very large. This is why you do not see them.

There are products that can do this.

But in a properly designed piping system, you do not need to do this.

The Custom designed system has its challenges. But the basics should still be adhered to.

Not trying to be preachy. Just had my fill of Eng.. saying it will work in the field and it doesn't.

 

I once had a walkin cooler doing the hammering , it was terrible , sounded like a machine gun after about 30 seconds of coming on

I was like .... what the hell is THAT

If I open the TXV more , so that it allowed TOO much freon to pass through , it would stop doing it

But then I got nervous and added an Accumulator to avoid slugging

What a mess that was

I was amazed it never damaged the compressor , little Semi hemi , ran for years afterwards