Is there an easy way to refill holdover plates with Eutectic solution

[phorvati]

Originally Posted by phorvati

That frost pic is from prior to installing accumulator. I no longer get that. I will troubleahoot restriction between compressor outlet and receiver king valve and report once i have the data.

Forum is frustrating, I can see how you guys get fed up with us greenhorns tinkering....but thank you for your inputs. I learned so much from this thread.

[Richard Kollmann]

Anytime there is frost or a cold spot on high pressure line there is a restriction phase changing refrigerant at that point instead of at TXV.

[OzeLouie]

Originally Posted by phorvati

That pic was a pic of receiver.

Thanks for this clearer picture of the unit. So it is a 'common old garden variety' reciprocating piston type compressor after all!!
My bad! Pease ignore my last post wrongly assuming it had a rotary and lets go back.

You reported that after a long run with the system suction isolated that it only achieved a 5" vacuum which indicates a faulty compressor. (Discharge valve reed damaged)
To be sure I suggest you do the following test before coming to any conclusions:

Test discharge valve reed:
A: Connect suction gauge as in sketch.
B: Close off SVC1 very firmly clockwise.
C: Run compressor for five minutes and note inches of vacuum achieved. (Should reach approx 25" if valve is ok)
D: Switch off compressor and note / time pressure rise. (Pressure will rise a little then remain constant if valve is ok)

E:Also after re-reading this thread there is the possibility that the problem is not liquid in the compressor but could be power related as Richard touched upon. If the compressor passes its test and you increase the high side pressure to correct level and you still have issues, then consider the power supply like the start capacitor also supply voltage at start up. Question where the power is from and how 'clean or otherwise it is!

Beside the diagram attached I have included a picture of a valve reed and as can be seen, they are very thin and brittle.

Regardless of what you end up doing, I strongly suggest getting your high side pressure to approx 120 PSIG or above for best performance.

[Richard Kollmann]

Louie, Explain to me the compressor overloading amperage? If high pressure reed valve or head gasket has failed?

[phorvati]

Originally Posted by OzeLouie

Thanks for this clearer picture of the unit. So it is a 'common old garden variety' reciprocating piston type compressor after all!!
My bad! Pease ignore my last post wrongly assuming it had a rotary and lets go back.

You reported that after a long run with the system suction isolated that it only achieved a 5" vacuum which indicates a faulty compressor. (Discharge valve reed damaged)
To be sure I suggest you do the following test before coming to any conclusions:

Test discharge valve reed:
A: Connect suction gauge as in sketch.
B: Close off SVC1 very firmly clockwise.
C: Run compressor for five minutes and note inches of vacuum achieved. (Should reach approx 25" if valve is ok)
D: Switch off compressor and note / time pressure rise. (Pressure will rise a little then remain constant if valve is ok)

E:Also after re-reading this thread there is the possibility that the problem is not liquid in the compressor but could be power related as Richard touched upon. If the compressor passes its test and you increase the high side pressure to correct level and you still have issues, then consider the power supply like the start capacitor also supply voltage at start up. Question where the power is from and how 'clean or otherwise it is!

Beside the diagram attached I have included a picture of a valve reed and as can be seen, they are very thin and brittle.

Regardless of what you end up doing, I strongly suggest getting your high side pressure to approx 120 PSIG or above for best performance.


Attachment 238076

I will thanks. in the meantime I will measure supply. I have a Solid state relay switching ON this compressor and it might have a drop. Ive had weird stuff happen across the relay. for instance I had 90V AC RMS on the load side ones.



Also I took out the water cooling loop and pressure rose to 90PSI and 5PSI

[Richard Kollmann]

Originally Posted by phorvati

I will thanks. in the meantime I will measure supply. I have a Solid state relay switching ON this compressor and it might have a drop. Ive had weird stuff happen across the relay. for instance I had 90V AC RMS on the load side ones.



Also I took out the water cooling loop and pressure rose to 90PSI and 5PSI

Is your boat still in Rhode Island if not what is air and water temperatures where boat is now?

[phorvati]

Originally Posted by Richard Kollmann

Is your boat still in Rhode Island if not what is air and water temperatures where boat is now?

Air in the engine room is in the 50s at night and 60s during the day. Water is 45F

[phorvati]

Also is 33c and 38c optimal refrigerant temperature leaving the second condenser?

I have another 120v thermostat. I could attach the bulb at top of air condenser and use thermostat to cycle water pump/fan.

I've been running without water pump, and freezer reaches set point much faster.

[Richard Kollmann]

The temperature leaving second condenser if at 38 C (100 F) will never produce Louie's 120 Psi requirement. If you turned off water pump and got 90 psi that is still not enough high pressure. Try also blocking some of the fan cooled condenser cooling raising refrigerant temperature at receiver to about 115 F this should produce 105 Psi high and no more than 120 psi maximum and no higher. I know getting pressure higher and hopefully filling sigh glass will not solve compressor's overload amperage but it will provide a reasonable test cooling super heat within evaporator solution tank until the overload problem is solved. .

I am still waiting on the high pressure reed or gasket failure question I asked Louie and whether owner will install a High pressure service port in the correct location to allow easier troubleshooting. I know low side at 5 inches of vacuum shows good flow but what about the theory of high pressure reed failure when 90 psi was being produced in high side tubing. If it turns out raising higher pressure restores the cooling then maybe we have an electronic problem causing the overload condition.

[phorvati]

Originally Posted by Richard Kollmann

The temperature leaving second condenser if at 38 C (100 F) will never produce Louie's 120 Psi requirement. If you turned off water pump and got 90 psi that is still not enough high pressure. Try also blocking some of the fan cooled condenser cooling raising refrigerant temperature at receiver to about 115 F this should produce 105 Psi high and no more than 120 psi maximum and no higher. I know getting pressure higher and hopefully filling sigh glass will not solve compressor's overload amperage but it will provide a reasonable test cooling super heat within evaporator solution tank until the overload problem is solved. .

I am still waiting on the high pressure reed or gasket failure question I asked Louie and whether owner will install a High pressure service port in the correct location to allow easier troubleshooting. I know low side at 5 inches of vacuum shows good flow but what about the theory of high pressure reed failure when 90 psi was being produced in high side tubing. If it turns out raising higher pressure restores the cooling then maybe we have an electronic problem causing the overload condition.

So what do you guys reccomend for ideal high pressure range?

[phorvati]

I'm not going to install high pressure service port just yet. I will add more refrigerant and disable fan/water pump to see if I get high pressure to a higher value.

Also I know when i shut off valve 2 next to filter/dryer and shut the unit, my pressures remain as they were during operation. 75psi and 5inches of Hg

If valve 2 is open and I shut the unit, my low side moves from 5 " Hg to 30psi. And my high side moves from 75psi to 45psi.

[Richard Kollmann]

Originally Posted by phorvati

So what do you guys reccomend for ideal high pressure range?

Volume of refrigerant in system and amount of condenser cooling will determine high side pressure. In the winter high side liquid pressure could be as low as 95 psi and in a tropical climate 135 psi until frost forms on plate's exterior surface.

Most likely you will not need water condenser pump cooling when air cooled condenser cooling medium is below 80 degrees F. You do not need to worry about refrigerant volume as refrigerant receiver if it is half filled at your winter temperatures, Extra space in receiver will absorb the expanded refrigerant volume in hot weather. It is also important that there be a high pressure switch set at 150 to 175 psi in your system if either or both condensers can not handle high explosive pressures.

Do not close king valve with compressor running without high pressure switch set correctly . I hope you are wearing eye and face protection.

[OzeLouie]

Originally Posted by Richard Kollmann

Louie, Explain to me the compressor overloading amperage? If high pressure reed valve or head gasket has failed?

No problem Richard but not easy to explain so best to first explain how refrigerant reacts in a perfect normal system / compressor then it will be easy to describe what this system is doing taking into account the symptoms reported by the OP.

Normal system.
When operating during a cooling cycle:
Refrigerant vapour enters the compressor via the suction pipe. This heat laden low pressure vapour occupies the entire interior of the compressor. The compressor draws this vapour into its compression chamber (bore and piston pump) where it is forced out via the discharge reed valve. This now high pressure vapour is contained inside a flexible pipe where it exits the compressor case and travels to the condenser. This is a continuous cycling process until the compressor stops running.

When stopped the discharge reed valve prevents the high pressure vapour returning backwards into the compressor case. Low pressure vapour from the now warm compressor usually migrates backwards and settles in the coldest part of the system, in this case into the hold over plate’s evaporator. Upon next start up pressure will have somewhat balanced out as vapour and there should be no liquid present inside the compressor housing or compressor’s compression chamber to prevent starting.

This system:
When operating during a cooling cycle:
Once started, operation is as normal albeit with abnormally low high side pressure.
When stopped the damaged reed valve allows high pressure refrigerant to pass backwards into the compressor, while low pressure vapour is migrating to the cold evaporator as described for a normal system. (The reed valve damage was determined as the compressor only achieved a 5” vacuum when pumped down during OP’s initial test. A further test to confirm this was requested but no result reported yet)

After a long off period the vapour dribbling backwards into the compression chamber can condense and form a pool of liquid in the chamber effectively able to restrict piston movement. This is more probable if the system is off for long periods and the compressor cools considerably. This system also has two condensers in series and is grossly over condensed, both issues can contribute to this phenomenon.

BTW the picture I posted earlier of a valve plate with damaged reed valve and head gasket, was caused similarly. In that system (not one of ours!) initially the reed was damaged by liquid slugging, the refrigerant charge was adjusted but eventually the comp failed when liquid settling in the compressor rammed out part of the gasket! We always cut open any compressor failure to determine cause.

My conclusion given the info supplied is that the compressors reed valve is faulty, the condensing temp is far too low and the issue of not starting could easily be a power supply problem anyway!! Set high pressure cut-out switch to off at 225PSI.

I hope this helps.

[phorvati]

This is a good photo of sight glass. It's in horizontal, sideways position and liquid is just below the green circle. This is near set point. Freezer cold plate fully frozen

[phorvati]

Originally Posted by phorvati

This is a good photo of sight glass. It's in horizontal, sideways position and liquid is just below the green circle. This is near set point. Freezer cold plate fully frozenAttachment 238225

Also I have not had failed startup fue to current overload in the last 3 Cycles. Ever since I disconnected the water cooling.