Float valve servicing in DR machines; advanced soldering...
Apr 7, 2024 14:53:57 GMT
cablehack, ckfan, and 2 more like this
Post by turbokinetic on Apr 7, 2024 14:53:57 GMT
I think I speak for many of us when I say that preserving these fridges is a passion of mine. We are fortunate to have the original GE manuals which were made when these were current models. GE wrote the manuals for the repair people of the day. They covered expected problems which might come up during the expected 25 year design life of these refrigerators. Now that it is going on 4 times the expected life, we are seeing problems which GE couldn't foresee and didn't cover in the manual.
Of these problems, we are seeing worn start-relays and thermostat controls. When the manuals were written, GE considered these throw-away parts which were not to be repaired. Now, there are no more, so they have to be carefully repaired and returned to service, or else unsightly and potentially risky modifications are required to use new parts.
Another area not covered by GE in the manuals is the ageing of the SO2 systems themselves. We are seeing restrictions and blockages in the systems which were not common 20 years ago. One of the areas which is most vulnerable is the outlet orifice of the float metering valve. This valve is where the liquid SO2 from the high side is metered into the evaporator. Even when the unit is off, there is some very small passing of SO2 through this orifice. This evaporates around the outlet of the float needle seat area, and leaves deposits. These deposits restrict, and eventually block the system at this point. This is happening to both the CK an DR machines. The repair process is the same, but the re-soldering of the line on the DR machines is more difficult due to the design of the float chamber assembly.
Please use caution while working on these. The SO2 is a noxious irritant and should be disposed of carefully before starting this work. The GE manual describes more than one method to accomplish this. Ensure the system is empty and work in a well ventilated area.
To access the blockage, you will need to remove the copper line from the bottom of the float chamber, so that the orifice is accessible. This is best done by cutting the line off flush, and then drilling out the remainder with a 1/4" drill bit. Once the port is open, the orifice can be cleaned with a pick tools and small gauge brass wire.
After the blockage is clear, a new line will need to be installed into the float chamber. This is where some people have encountered difficulties. It is very important to use the exact materials specified here. You cannot use any sort of grease or paste flux. You cannot use plumbing solder. Use only Harris StayBrite-8 solder; and Harris StayClean Liquid (acid) flux. I cannot stress this enough, the paste form of the StayClean flux will not work. It is mandatory to use liquid (acid) flux. I think Harris could do a better job differentiating between these two products, but that is beside the point.
It's not wise to use a higher temperature brazing process, due to the possibility of damaging the internal works of the float chamber. The StayBrite-8 and liquid (acid) flux will solder dissimilar materials without the need for red heat.
Please watch this video for some pointers on making this repair.
Sincerely,
David
Of these problems, we are seeing worn start-relays and thermostat controls. When the manuals were written, GE considered these throw-away parts which were not to be repaired. Now, there are no more, so they have to be carefully repaired and returned to service, or else unsightly and potentially risky modifications are required to use new parts.
Another area not covered by GE in the manuals is the ageing of the SO2 systems themselves. We are seeing restrictions and blockages in the systems which were not common 20 years ago. One of the areas which is most vulnerable is the outlet orifice of the float metering valve. This valve is where the liquid SO2 from the high side is metered into the evaporator. Even when the unit is off, there is some very small passing of SO2 through this orifice. This evaporates around the outlet of the float needle seat area, and leaves deposits. These deposits restrict, and eventually block the system at this point. This is happening to both the CK an DR machines. The repair process is the same, but the re-soldering of the line on the DR machines is more difficult due to the design of the float chamber assembly.
Please use caution while working on these. The SO2 is a noxious irritant and should be disposed of carefully before starting this work. The GE manual describes more than one method to accomplish this. Ensure the system is empty and work in a well ventilated area.
To access the blockage, you will need to remove the copper line from the bottom of the float chamber, so that the orifice is accessible. This is best done by cutting the line off flush, and then drilling out the remainder with a 1/4" drill bit. Once the port is open, the orifice can be cleaned with a pick tools and small gauge brass wire.
After the blockage is clear, a new line will need to be installed into the float chamber. This is where some people have encountered difficulties. It is very important to use the exact materials specified here. You cannot use any sort of grease or paste flux. You cannot use plumbing solder. Use only Harris StayBrite-8 solder; and Harris StayClean Liquid (acid) flux. I cannot stress this enough, the paste form of the StayClean flux will not work. It is mandatory to use liquid (acid) flux. I think Harris could do a better job differentiating between these two products, but that is beside the point.
It's not wise to use a higher temperature brazing process, due to the possibility of damaging the internal works of the float chamber. The StayBrite-8 and liquid (acid) flux will solder dissimilar materials without the need for red heat.
Please watch this video for some pointers on making this repair.
Sincerely,
David
https://youtu.be/7udN_Bx-NxU