Hoses/Types and Applications w/ NAVAC – Short #198

In this short episode of the HVAC School podcast, Bryan talks about hoses and their various types and applications, particularly focusing on NAVAC hoses.

Charging hoses (NAVAC: NH5 and NH5L) ideally shouldn't be longer than 5-6 feet, as the longer the hose, the more refrigerant it will hold. Manifold gauges also have leak points, so it's usually better to use probes instead of manifolds to help with charging. Charging hoses with ball valves (NH5S and NH5SC) can help you control the flow and are great for recovery. Whenever you use charging hoses, they will have a core depressor on one side only (usually the 45-degree side, if applicable); the right amount should be exposed, and the seal should be in good shape.

Larger-diameter hoses with higher burst pressure are advantageous for recovery (though it's better to have separate hoses for recovery and evacuation). Larger-diameter hoses of a shorter length will allow you to get a higher flow rate, including cases where you have 1/4″ connectors (though the F1028 & F1029 Rapid Y connection fittings can help out with those cases where you have 1/4″ connectors by giving you the ability to connect two 3/8″ hoses); hoses with a diameter of 3/8″ are usually the biggest recommended ones for recovery. NAVAC's recovery hoses are the NHR38AA and NHR38AB.

Evacuation hoses are even bigger. Some good evacuation hoses include the NH34AB and NH34AC; they are short 3/4″ hoses that are vacuum-rated and quite flexible. NAVAC also has smaller hoses, which tend to look more like recovery hoses. You do not want to use 1/4″ hoses and core depressors for evacuation, but they are good for charging.

Check out all of the hoses NAVAC has to offer at https://navacglobal.com/products-by-category/hoses-kits/.

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Author:

Bryan Orr

Company: HVAC School

Position: Founder

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HVAC School – For Techs, By Techs

Real training for HVAC ( Heating, Ventilation, Air Conditioning and Refrigeration) Technicians. Including recorded tech training, interviews, diagnostics and general conversations about the trade.

In today’s podcast, Bryan talks with legendary Hydronics author and trainer Dan Holohan about the history of steam heating and some practical applications of old ideas. Recently, Dan has been working on more novels, having published two of them over the past few months.

Steam heating is a “lost art” nowadays; it has become increasingly uncommon and has been disappearing since the Vietnam War. Many people who understood steam heating either retired or died after the Vietnam War. Many elements of steam heating are difficult to understand or surprising. (For example, steam pressure has a surprising relationship with velocity: low-pressure steam moves through piping much more quickly than high-pressure steam.) So, Dan Holohan is on a mission to revive that knowledge and teach the newer generations about the lost art.

There are many older steam heating systems still operating today, especially in the older large buildings in New York. Dan learned a lot about steam heating when working on these old systems and optimizing them. Most of the time, he optimized those systems by removing unnecessary accessories, not by adding components like steam traps.

Many old boilers used coal as a heat source. Nowadays, many old boilers have been fitted with conversion oil burners with thermostats, but they are still piped for coal. Some systems now have multiple risers or massive vents on the main riser to prevent the thermostats from getting too hot too early and satisfying the thermostat too early. We call that master venting, which reduces pressure and allows steam to move very quickly and efficiently.

Dan also discusses:

The 2-PSI standard
Transportation metaphors for BTUs in steam
Harmful renovations for old boilers
Replacement vs. restoration mindsets
Gaps in steam boiler education
Monopolizing the market if you HAVE the education
Boiler piping and venting
Two-pipe vs one-pipe steam

Find out more about Dan and hydronic heating at HeatingHelp.com.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium. Subscribe to our podcast on your iPhone or Android. Subscribe to our YouTube channel. Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android.