Refrigerant Hoses / Lines avoiding liquid burns !

Firstly I do apologise if I have asked this in the wrong forum area ?

What I am trying to establish is whether there are any ways to not get my skin removed due to bad gas burns when taking my manifold lines off of high side/ discharge ports on R22 and 410A units etc..??

I have often thought of spending on quick release connectors like the ones you screw on the collar then depress the little spring loaded lever and try to get them to clip on ! but I've heard a lot of eng's say they're no good, pop off, leak etc..

Recently my supervisor eng said get ball valve ones then to take off, lock off valve on high side and then open high side manifold valve and let liquid left in hose be sucked back into unit via low side hose. As apparently the burns come from liquid left in hose not from unit port when you take off the line / hose ??

Its got to the point where I don't want to put my gauges onto units as I hate getting burnt and big clumpy gloves are too awkward to undo lines quickly so also lose lots more refrigerant.

Also on say Daikin VRV III S and similar how do you know which of all the many stubs and ports are H.P. and which are L.P. ??? please someone help a less experienced engineer as I keep having to put high side on just in case its not LP so I don't wreck my gauges !! :eek:

First thing to do is to update your hoses to ones with ball valves fitted. These have the last 5"-6" beyond the valve so there is still a little liquid left but not so much.

You can also get adaptors to fit at the end of your hoses which contain a ball valve, these will reduce the amount of liquid again but can restrict access due to the longer length of solid fittings.

Your supervisors suggestion is the way to go, it also minimises the amount of refrigerant removed from the system.

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Originally Posted by daddy33

What I am trying to establish is whether there are any ways to not get my skin removed due to bad gas burns when taking my manifold lines off of high side/discharge ports on R22 and 410A units etc..??

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Can't you just put on some leather gloves when connecting the gauges, like you're supposed to...per health and safety?

Gloves and goggles are plain sense, but no engineer uses them except when doing their safe handling assessment. Soon as they get outside, that's the end of all that nonsense, eh?

But that would solve the skin worries. :cool:

Hoses with ball valves are the way to go, quick release couplers are ok when new but i've always find they leak eventually & they're not cheap !!

There's couple of other things you can do to help;
Try adjusting the little depressor thats fitted into the end of your hoses so that it doesn't protrude so far & opens the schrader valve less.
Take your LP line off when the units running & the pressures at it's lowest, & the HP line off when the units stopped, the pressure's equalised & is at it's lowest possible..
Also if you initially purge your maniflod & not just the hoses, when you want to remove the high side, isolate using the ball valve on the end of the HP hose then purge the high side hose through the manifold & LP line.
Although it won't help when you take the HP hose off it'll stop the hose being full of high pressure liquid when not being used..
If you've got a fitting thats particularly bad use a schrader core removal tool, take the core out & isolate with the valve on the tool then replace the core when you've finished.

Gloves are always a good idea either way, at the very least until your more used to dealing with the fittings..

A manifold with 2 x HP gauges on is always a good idea with heatpumps, handy for pressure testing too.
Also some better quality LP gauges will handle a higher pressure without being damaged.

Even if they're labelled up, the only way to be certain what pressure's on a port is to trace the pipework & understand the system, it'll get easier with experience. But if your uncertain just play safe & use the HP side, the scale maybe not as defined as the LP but it's better than blowing a gauge..

Ginge :)

If you have both high and low side hoses conntected and want to remove them then, 1. Backseat the high side valve on the system 2. open the manifold valves between the high and low side slowly (this releases the high side pressure into the low side) any liquid will move into the low side and boil off from your hoses 3. once the pressures have equalised (high side guage and low side guage will read the same) backseat the low side valve on the system. now all you have is some low side pressure in your guages with no liquid

Mastercool do a set of 6ft lines with ball valves part number is 90262-72

Neoprene diving gloves are great for this task nice and thin

Or some vinyl gloves like the mechanics and my dentist seem to use

Also on say Daikin VRV III S and similar how do you know which of all the many stubs and ports are H.P. and which are L.P. ??? please someone help a less experienced engineer as I keep having to put high side on just in case its not LP so I don't wreck my gauges !! :eek:[/quote]

Follow pipes out of compressor untill you find a scroeder valve.
LP = cold
HP = hot

Question

What are you trying to gain by putting on gauges?

If your not sure where to put them then they are not going to tell you anything.
Hard to tell at the best of times.

Variable speed compressor controlled by a pressure transducer with different indoor unit connection ratio's. Also you have different ambients and air on temps of the indoors. If you know what you are looking at you can get a indication but other then that there is too many variables.
If the system is working with no capacity issues and no fault codes (Eg High Discharge Temp). Then things are fine. If it aint broke dont try to fix it.

Also a poor mans way of taking off gauges is to keep the pressure on the gauge rubber against the valve body while you unscrew your gauge line . If you keep the pressure on it and keep it straight it will stay sealed. once fully undone release the pressure off the gauge hose at quickly put the end into a rag to catch any oil.

Your playing with dangerous stuff here . If your not sure best to leave it alone or it can kill you.

Cheers