In this video we're going to talk quickly about two different types of gas valves and exactly how to set and adjust the gas pressure. Quick warning adjusting gas pressure is definitely something that should be done by a professional and even then we need to be doing things like clocking the gas meter to check for our input, as well as doing a combustion analysis whenever we're making an adjustment. But for those who are newer to the trade or who have never seen it done before, i want you to get a really good sense of how to adjust a gas valve properly. So the first valve we're going to look at is a very basic single stage.

Gas valve the first thing we need to do is shut off the gas hand valve otherwise called the gas that enters the gas valve before we pull out the plugs, and you have two different plugs. The first one that we're going to remove is the inlet plug and then the second one we're going to remove. Is the outlet plug we're going to put some brass adapters with barb fittings? This is a field piece manometer. These come actually with these little fittings that we're going to show and we're going to attach to the inlet, which is the gas pressure coming in, as well as the outlet otherwise known as manifold pressure.

So when i say manifold pressure, i'm talking about the outlet of the valve going into the burners now quickly, this particular manometer that i'm going to show you is very similar to many manometers out there, where it can measure either a single pressure either p1 or p2 P1, in this case, being set up as the inlet and p2 being set up as the manifold pressure. But then it will also show delta p or pressure difference between the two, which isn't particularly useful when you have both hoses connected. So really we're going to be paying attention to the p1 and p2 pressures, initially we're, starting with the inlet pressure, which is eight inches of water column. And then we're going to switch over to p2, which is the outlet pressure which is starting off at three inches of water column.

Next, we're going to remove the cover cap, which covers the adjustment screw that's made of brass and then in order to increase our manifold pressure, our outlet pressure. We are going to turn a flat blade, screwdriver clockwise, so turning it. Clockwise will actually increase the outlet or manifold pressure and, in turn, that p2 number is going to change just because you're changing the pressure differential between the inlet and the outlet, you shouldn't actually see any significant drop in inlet pressure as you adjust your manifold pressure. Now again, you do want to make sure that your inlet pressure is within the allowable range, in this case we're just showing making an adjustment now again in order to make an adjustment, you would need to know that an adjustment was needed to be made based on The manufacturer's recommendations, as well as checking the gas input to the appliance via clocking the meter and monitoring your combustion to make sure that you're not over or under fired now, once we're done, we shut off the gas inlet valve again, we remove our ports and we Make sure to put back in our port plugs before we turn on the gas again.

This is very, very important for safety, alright, so that is a basic kind of standard single stage valve and it has the basic test plug configuration that you would see most commonly now. This next valve that we're going to show is actually a two-stage gemini valve now. Gemini is a trade name from white rogers, but this valve is fairly common. You will see it out there.

It's been around for quite a few years, i'm not sure exactly all the models that still contain it, but you will see it out there and it is very different with how it works initially you're, going to do the same step in that you're going to shut Off the gas, but now you're going to notice it has these two little ports where you use a smaller allen, wrench and rather than taking the port all the way out you just loosen it a couple turns so you do not pull it all the way out. You just loosen it a couple turns and the gas then leaks around the screw so again notice. Gas pressure is already off we're going to adjust these out and then we're going to place tubing adapters over them, which again field piece sends with many of their manometer models, or you can use some surgical tubing if you wish and you're going to place that over With then, some barb fittings which attach to your manometer or you, could use the surgical tubing all the way back, just depending on the the barb size on your manometer itself, but this would be a common configuration once again. This is a p1p2 valve with a delta p, so the top number that you're seeing is either p1 or p2 and the bottom bottom number is the delta p, meaning the differential between the two.

So we're not going to pay much attention to that bottom number. We're looking at the top number and initially here we're starting with our inlet pressure, which again eight inches of water column. So we can see on our low fire it's at what starts at one and as we turn it in. It goes up to 1.5 and now, when we run it in high fire and again, this is something that you would do in your controls.

You would, you know, run it up to high fire. Now you can see we're adjusting our high fire setting so on this valve quite quite a few different things. We have both low and high fire adjustments underneath our brass caps and we have a completely different test port configuration where you place it all the way over. The ports and you do not pull them all the way out.

So now we're going to shut off our gas valve again we're going to pull these off, and now we're going to remember to tighten these back down again just to snug anytime. You do any sort of taking plugs out or anything like that. You want to use a combustible gas leak, detector to check and also a little bit of soap bubbles can't hurt as well just to make sure you don't leave any leaks whatsoever now again reminder this is for professionals who are trained, and you need to accompany this With other gas test procedures to ensure that you are not over firing or under firing, the appliance always follow your manufacturer's specifications. That's it a standard gas valve adjusting gas pressure as well as a white rogers gemini, two stage valve thanks for watching we'll catch you on the next video thanks for watching our video.

If you enjoyed it and got something out of it, if you wouldn't mind hitting the thumbs up button to like the video subscribe to the channel and click, the notifications bell to be notified when new videos come out, hvac school is far more than a youtube channel. You can find out more by going to hvacrschool.com, which is our website and hub for all of our content, including tech tips, videos, podcasts and so much more. You can also subscribe to the podcast on any podcast app of your choosing. You can also join our facebook group if you want to weigh in on the conversation yourself thanks again for watching you.