Quote:
Originally Posted by stevehull
My old dual pressure manifold finally bit the dust. Over the years I fixed hoses, replaced dial plastic faces, put new o rings in the valves, but it got dropped and the pot metal body literally broke in half . . . .
I think I got it at a yard sale some 30+ years ago for ~$3. Time to look for a new one. Need to do R410, R 22, etc.
Suggestions on e-Bay, Amazon, Grainger, Northern Tool, etc? I see prices from $20 all the way up to nearly $100 (Yellow Jacket brand). I suspect something in the middle might be about right, but as always, you guys will know more than I do.
I understand that low loss coupling fittings are now standard, but some of the specs don't even mention them.
Thanks in advance.
Steve
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Most of the cheapie ones are just that. Much of the units are paper and plastic. When you have a problem, it is not easy or economical to find parts for them. You just throw them away and buy new. Not quite disposable, but close. The money you spend on them goes pretty much straight to Hong Kong or Guangzhou.
The same main names are still around: Yellow Jacket, Robinair, JB are the most widely available. Testo and Fieldpiece are the top-shelf, pro-lines (financing available). They sell different levels of durability and convenience for different prices. When you have problems, parts can be found locally today. The units are at least assembled and packed in the USA, and the ones that aren't knock-offs (beware of fleabay and amazon listings too good to be true) are only available through authorized resellers. So at least a fraction of what you spend ends up in friendly pockets.
There are two main types of manifolds: two-way and four-way. The two-way manifolds are the traditional style: one valve for the low side, and one valve for the high side. When opened, the valve is opened to the center port. The four-way valves are new: same two valves as the two way, and two more. There are two center ports, each with its own valve. One port connects to the vacuum pump and reclaim cylinder. The other port connects to the purge or charging gas cylinder. Prevents having to do lots of things between operations.
The less expensive manifolds still have analog dial gauges on them. If you only want to buy one manifold, make sure the faces have scales for the refrigerants you plan on using. Most are faced for either older, lower pressure refrigerants (R12/R134/R22) or newer, high pressure (R410a/whatever) refrigerants. Not many of them have both. The high pressure can be used for low-pressure, but readings are not as accurate. The low pressure cannot be used for high pressure, it will kill the gauges' accuracy when they peg past the stops.
The more expensive manifolds have digital gauges. These range from simple equivalents of the analog gauges with a digital readout to fully automatic. The more automatic gauges can display saturation temperatures for refrigerants they support. The automatic gauges have thermometer clamp sensors to rig into a working unit and calculate superheat in real time for you. The super automatic gauges are programmable, and basically tell you what to do throughout whatever process you select from a menu. What valves to open or close, turn on vacuum pump, etc. The most expensive ones are wireless. You connect sensor modules to various places, and voila!
Hoses are high pressure or low pressure also. The different types of systems all have different fittings nowadays. Old school, R12 old cars and R22 split systems are pretty much the only things that use 1/4" flare fittings any more. The R410a split units use 5/16" flare, the R134a car fittings are custom, most mini-split units also have custom fittings. Luckily, the usual manufacturers sell adapter kits that cover nearly all the units you will encounter.