How does line length affect refrigerant charge?

When you increase the size of a liquid line, it just robs more refrigerant from the places where it can do some good: the coils.

What is the maximum suction line velocity that must be considered when sizing a system?

Acceptable velocities for horizontal suction lines (with proper 1/2” slope per 10′ run) range from 500′ to more than 1500′ per minute. A properly sized line at the low range of its capacity will have a low velocity and one at full capacity will have velocities exceeding 1500 fpm.

How many ounces is a line of refrigerant per foot?

The manufacturer’s factory charge of 8 lb 7 oz includes enough refrigerant for 15′ of 7/8” and 15′ of 3/8” line set. How much extra refrigerant needs to be added to the factory charge for an accurate system charge? For the 3/8” liquid line, add . 54 oz per foot as seen in the “Refrigerant Weight Per Foot” chart.

How far can you run a mini split line?

In some cases, the space from one unit to another may be slightly shorter at 15 feet, so you’d need a line that’s about as long. The longest mini split line you can get is around 50 feet, sometimes double that, but in most situations, that should be considered way, way too much line.

How do you measure a refrigerant pipe?

Refrigeration tubing is measured by it’s outside diameter or O.D.: ¼, ½, 5/8, ¾, 7/8, 1-1/8, 1-3/8, 1-5/8, etc. Plumbing tubing is measured by it’s inside diameter or I.D. : 1/8, ¼, ½, ¾, 1, 1-1/4, 1-1/2, 1-3/4,etc.

Is the liquid line bigger than the suction line?

The larger line typically carries a cool gas and is insulated. This is commonly referred to as the suction line, but it is also called the return line or vapor line. The smaller uninsulated line typically carries a warm liquid. It is most often called the liquid line.

How much extra is 410A per foot of Lineset?

For 15 feet of line set and a matched indoor coil, outdoor units are pre-charged at the factory. For line lengths greater than 15 feet, add 0.6 oz. Refrigerant per foot of line length.

What should the PSI be on a 410A refrigerant?

An R-410A system may be operating at over 600 psi and not have the high-pressure safety switch open. Carrier has a unit with the high-pressure switch set at 610 psi. It resets at about 420 psi. The same model has a loss-of-charge liquid-line switch that opens at about 20 psi and resets at about 45 psi.

What are the general guidelines for estimating refrigerant piping?

General Guidelines In estimating refrigerant piping systems, several key guidelines should be kept in mind: ] All local, state, and national codes must be followed. ] Piping runs should always be kept as short as possible. ] The use of long-radius elbows over standard elbows is preferred.

What should the velocities of refrigerant be?

Refrigerant velocities in vertical lines should be at least 1500 ft/min to ensure good oil return; velocities in horizontal lines should be at least 750 ft/min. Suva refrigerants Section 1 page .. 4 Refrigerant Piping Application Considerations • System design for MINIMUM pressure drop. Pressure loss results in: a. decrease in thermal capacity b.

How long should a refrigerant line be for an indoor cooling system?

For cooling systems where the indoor and outdoor sections are installed at the same elevation, refrigerant line sizes can usually be matched with the factory supplied fittings. There are exceptions for total line lengths exceeding 75 feet where pressure drop limitations are exceeded. Refer to Long Line Set section.