Fitting an expansion valve question

[Larry2]

Isn't she pretty? This is the expansion valve from my decrepit heat pump system. It's connected by flare connection from the liquid line. The other side is some sort of threaded fitting also. That connects to a distritubtor located on the other side of the metal housing. It has multiple smaller tubes connecting to various points on the coil. That distributor is 3/8" tube as well. However the flare nut is a different larger size hex. It bolts into the position where a piston control or orifice slug would fit as an alternative. The expansion valve was an upgrade for these systems years ago and was provided as a field installed kit.

This is in my heat pump/AC system. I believe it has a check valve so during heat mode gas can flow the alternate direction. I think that is why it has a second brass section and I'm thinking the bottom connection is between the two brass bodies is the alternate flow. I've looked online at Sporlan.com and downloaded their catalog of valves. I don't see any constructed in this manner. The part number is Y-930-3-VGA and Lennox appied their own tag LB57302DC. I believe the 3 in the number means 3 ton. It is installed in a 3-1/2 ton system.

My question is how to specify the replacement valve part number. I'm giving serious consideration to replacing the outdoor compressor or perhaps the entire outdoor condensor unit with one having 4 tons capacity. The indoor coil is rated for 4 tons cooling or I would go larger since my system is undersized.

[frank]

Where's the pics Larry?

[Brian_UK]

I can see it Frank, too much sweat getting in your eyes

[frank]

It's loaded now I can SEE

[Brian_UK]

Hi Larry, checking through the Sporlan literature there are two .pdf files which may be of help to you.

1. 210-60 which details their TEVs and show that a valve with a 'Y' designation plus a number (930 in your case) means a special made for a manufacturer and "should be ordered through them". THe VGA means an R22 valve.

2. Of more use would be file 10-10-5 which shows the RC heat pump TEV with built in non-return valve.

Have a look and see if this helps.

[Larry2]

Thanks much Brian. I'm reviewing that document but I don't see my application listed.

What does ODF stand for? Outer Diameter Finished? I've not heard that term before.

In my photo, would these valve connections be SAE 3/8 inlet, 1/2 out? The threaded portion of the inlet seems to measure around 1/2".

The valve in my 3-1/2 ton system is a 3 ton valve. Should this have been a 4 ton valve instead? The contractor reinstalled this txv from the original 2-1/2 ton system. This is why I'm reluctant to request the item through a Lennox parts shop by this part number marked on the tag. I don't know that the number is correct for my application. This is the same part used on my other 3 ton system. If another vendor's heat pump outdoor unit were connected to this coil, would I use the txv kit from the new vendors condensor?

These replacement valves all have an equalizer port. My system doesn't have a line for that connection. Is that port left open and the stem adjusted to suit, or would I need a different valve? The data sheet refers to this product line as universal, fitting everything.

[Peter_1]

ODF = Outside Diameter Flared
ODS = Outside Diameter Soldered

You can figure out if your valve is working/regulating now correct if the SH is regulated the right way and stays stable on that value.

[frank]

These replacement valves all have an equalizer port. My system doesn't have a line for that connection. Is that port left open and the stem adjusted to suit, or would I need a different valve?

There are various types of TEV. Internally equalised and Externally equalised are 2. If the one you have does not have an equalising port then it is internally equalised. You cannot just replace one with the other.

You can fit the externally equalised TEV to your system though, you will just have to connect up the equailsation port to your suction line.

have a read here http://www.sporlan.com/10-9.pdf

[Brian_UK]

I'm reviewing that document but I don't see my application listed.

Document 10-10-5 talks about an RC valve type which is designed for heat pump use with a built in check valve.

[Larry2]

The RC valves all seem to be equalized with the added suction line tube to the spring side of the diaphram. I was hoping to find a drop-in swap for what is already there. My system doesn't have this connection. Reading through the Sporlan explantion Frank gives the link too, it seems this feature extends performance range, but probably not essential for my use.

However, looking through Sporlan's web site, I don't see an internal valve that has the check valve suiting it to heat pump use. I guess this item has to be obtained directly from Lennox. The problem is I don't know the correct part number because I may have the wrong sized valve for my system.

[Andy]

The RC valves all seem to be equalized with the added suction line tube to the spring side of the diaphram. I was hoping to find a drop-in swap for what is already there. My system doesn't have this connection. Reading through the Sporlan explantion Frank gives the link too, it seems this feature extends performance range, but probably not essential for my use.

However, looking through Sporlan's web site, I don't see an internal valve that has the check valve suiting it to heat pump use. I guess this item has to be obtained directly from Lennox. The problem is I don't know the correct part number because I may have the wrong sized valve for my system.

Expansion valves are sized to the condensing unit. If your outdoor was 3 1/2 ton and your indoor 4 ton you would fit a 3 1/2 ton valve.

At that size I would advise an external equalised valve, it's only a matter of brazing on a bit of copper pipe, the bigger job you will have is recovering the gas anyway (you may need a mechanic with a recovery unit on site).

Kind Regards Andy

[Larry2]

As I understand it, the equalizer line is soldered to the suction line on the top surface of the pipe. Is this correct? Since a 1/4" line is supplied, does one simply drill a 1/4" hole and braze the connection? How do you keep chips from entering the pipe when drilling the hole?

I'm looking into the recovery cylinders, recovery pump and all that. I think these will be worth owning because of the cost for service and the fact that most service companies here want to bin the whole system rather than make repairs.

[Peter_1]

I usually make a small hole with my torch or drill the hole with a slight overpressure.

[Larry2]

That's an interesting way, Peter. I'm going to get my torch out and try that on some scrap. That way would surely not leave any bits to circulate in the system, assuming one can make a suitably sized hole.

The text books all call for nitrogen to be inside the pipes while brazing so it doesn't oxidize and release junk. Is there any reason I couldn't use argon instead? I have argon around here for my TIG welder, already configured with a regulator.

[Peter_1]

Another way I did it many times.
Make sure that you have slightly overpressure and solder a 1/4 connection on the tube, something like this
Take then a small drill and make a hole through the soldered piece. The debris will be blown away.

If you're used to do it, then you even can solder it with a high silver rod on a tube with evaporating pressure or stand-still pressure on it.

You can also use argon - as long as it is an inert gas and can't explode - but argon is far more expensive.

[Larry2]

That's interesting Peter. Thanks for revealing all your trade secrets. I guess after that, you can put a 1/4 tube through or use it with a 1/4 flare.

You method reminds me of the difference between a homeowner and a plumber changing out an electric heating element in a water tank. Both will shut off the mains and the water, hopefully. The homeowner will drain 30 pails of water, climb the stairs 30 times and empty out in the sink. With the tank emplty, then he changes the element. A plumber will unscrew the element, then pull it out with one hand and push the fresh one through the hole with the other. After threading it tight, he's done and only looses a splash or two. The column of water in the tank creates a vacuum at the top of the tank, so the water inside is a bit lazy about gushing out. The difference in these two methods, maybe an hour. Time is money.

I picked up a used Promax Minimax refrigerant recovery pump yesterday. I also bid and won a new 4 ton copeland compressor. I have a few things more to gather up, such as a recovery cylinder, vacuum pump and some odds and ends, then I will be equipped to bring my equipment up to snuff.

On this expansion valve device, I have 3/8" copper tubes connected to both ends. However, the outlet side has larger threads than the inlet connection. You can see the difference in connections in my photo on page one. In the specification's sheet at
http://www.sporlan.com/10-10-5.htm, they list connections for their RCVE-4-GA as 1/2 ODF inlet and outlet. I guess I would have to use adapters to bring 3/8" up to 1/2" sweat connections. Or maybe look for the OEM valve for a 4 ton system. In my photo, are these fittings 3/8 SAE flare inlet and 1/2" SAE flare outlet? The outlet size is 3/8 tubing that emerges from the refrigerant distributor on the other side of the cabinet wall. I didn't know you could flare 3/8" for connection to a 1/2" connection. What is it I am looking at here?

[Brian_UK]

Larry, it is possible to flare a 3/8" tube to fit a 1/2" fitting. Extend moretube through the flaring tool and make the flare SLOWLY.

[US Iceman]

Or, you can take a a short piece of 1/2" tubing and flare one end. Ream out the other end of the 1/2" tubing, and slide it into a piece of 3/8" tubing which has been reamed out. Braze the slip joint together and you're done.

When you are drilling out the hole for the 1/4" stub as Peter suggested, take a center punch and make a slight impression on the tubing where you want the hole to be. Otherwise the drill bit will skip all over the tubing.

[Larry2]

Larry, it is possible to flare a 3/8" tube to fit a 1/2" fitting. Extend moretube through the flaring tool and make the flare SLOWLY.

Is that a 1/2" SAE flare fitting I am looking at on the outlet side of the txv? I've not been able to find a mechanical drawing online for these threaded parts. That side has a larger flare nut, but it's still 3/8" tube. It passes through the wall into the air handler, then it makes a 90* bend to the refrigeration distributor. That side is all factory work as well. Really, there is not much room to cut things off and solder a different valve, so I would like to specify the txv to fit that fitting where it enters the evaporator, even if I need to make changes to the inlet side of the txv.

I've put an email into a lennox parts retailer, looking for the oem valve. I'm reading on the Parker site that for 3-1/2 tons through 5 tons, they recommend a txv that is larger than 3 tons. They offer a 3-1/2 through 5 ton valve. I think my system has the wrong valve in it. I'm not convinced that is causing my problems,but surely it can't help.

[Larry2]

I found the manual for the coil/blower unit. Here is a drawing of the expansion valve conversion.


The installer bolted the expansion valve directly to the distributor without the strainer device and without the adaptor tube. I'm thinking the installer cut off the male fitting on my coil and installed a flare nut and flared the end. Is anyone here familiar with Lennox gear to know for sure? Will it be sufficient to install a filter/drier in the absence of the strainer?

[boanerge]

hi friends ,I'm searching for the specifications of this sporlan TXP Y ARZBP/10 .Do you know where can I get it. Tanks