How to Measure Gas Pressure - Kalos Meeting
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- เผยแพร่เมื่อ 12 มิ.ย. 2024
- In this Kalos Meeting, we discuss How to Measure Gas Pressure. We cover the basics of measuring and setting gas pressure. The importance of understanding your manometer and zeroing it correctly as well as some of the other top Gas safety tips and practices.
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Bryan, I had to adjust gas valve pressure down to 2” wc on a single stage 80k BTu furnace to get below manufacturers range of 50 temp rise. This was after adjusting airflow with a fieldpiece hot wire anemometer to 1200 cfm with .7 esp. Is this ok to lower the gas pressure that low in order to get within manufacturers temp rise? The system is 2 years old, with a 3 ton heat pump.
@Timothy Salomon in pa, and hot wire is brand new
@Timothy Salomon yes, it’s a 96%. The specs are 25 - 55 temp rise. I like to adjust slightly lower than max range. It should be ok on a single stage valve, since two stage gas valves typically run at 1.6” wc on low fire.
@Timothy Salomon I went there on a PM, and noticed a 65 temp rise. My company replaced furnace and heat pump with the same capacity in a 3000 sqft house. I was concerned of overheating the heat exchanger and possibly premature failure. I explained to the customer derating the capacity was necessary to ensure proper operation per man. specs.
I literally did the exact same thing on Saturday for a family member who wanted to replace a defunct eac with a media filter. 85 degree temp rise. After I cleaned the blower and secondary heat exchanger with no filter in place.
Quick point though, I’ve found that the hot wire anemometer tends to skew high. If you had a 70 degree temp rise then you probably had more like 1000 cfm or less
@@jammin345 with low gas pressure are you not worried that the flame is to low and will fill the heat exchanger with sud? (If I spelled that right)
i like to spend the extra 10-20 minutes watching this channel vs. any other hvac channel on yt. i never have been good at class room settings... BUT! this mans teaching methods click with me, i dont know why. but i really enjoy learning from this guy.
Thank you, as usual very informative!
Great HVAC Residential Basics knowledge! Great job Bryan👍
Very good video and this is coming from someone who's been in the gas utility industry for over 35 years & over 10,000 emergency calls ran. I was also impressed that this is coming out of a technical school in Florida, a State not really dominant in the Natural Gas utility industry like we are in the midwest and northern states. I would like to add some terms we use in the industry that may help in your teaching.# 1 when dealing with regulators from the transmission line to the built-in gas valve regulators at the appliances , gas pressures are considered working and lock up pressures.#2 when explaining the manometer you may want to use an actual U tube manometer in your demonstration, so the students may get a better understanding of what the electronic manometer is doing and based on. The actual U tube manometer is what we still use in the utility industry today, due to documenting gas pressures in case of an incident ( U tube manometer are absolute , with no need for calibrations. Due to liability concerns in our industry all electronic instruments used must be calibrated once a month & there are utilities that use the electronic manometer but it does add to their documentation process for instrument accuracy).#3 things you may want to add to your presentation , fuel run sizing, working pressure drop across the fuel runs & clocking the gas meter to determine BTU output of an appliance.
Hopefully some of these things help , at least fuel for thought. Keep up the great work, the world could use more instructors like you.
Not a technical school... per se, these are in house meetings at a commercial company that thankfully, is not afraid to share good info.
Enjoy your videos.Great teacher 👨🏫
Thank you for all your videos man
Thank you very much well-explained great job once again
Thanks for the information !!
Great beginners info.
Great class
Great Bryn once again
Right on good info
Somewhere near the end of this started thinking about looking for a pool heater and running a few loops of hydronic heat under my 80 yr old gulf coast raised cottage!
Combustion air screens 12" from the top of the wall and 12" from the bottom of the wall. Especially in a closet. After making any gas pressure adjustments let the system stabilize for a few minutes before adjusting any further. Up here in the NE we have almost all gas and a little oil still around. I come from cali, so i am used to heat pumps and gas. Its fairly easy to adjust and understand.
Use B-vent instead of single wall pipe. B-vent will help with less condensation in the flue vs single wall, which gives up its thermal energy to the surrounding environment. Here in the NE you see mostly single wall flue going into a chimney and it creates condensation, also the chimney is usually oversized for the furnace and definitely helps promote condensation and draft issues
Many of the high efficiency boilers won't even have a manifold pressure listed or even a manifold pressure test port on their gas valves. Only measure is inlet and the rest is adjusting based on combustion analysis on lowest/highest modulations. Another good tip to look for by techs new to gas is checking if the unit wasn't incorrectly converted from Nat to LP or vice versa.
Great!!
At about 25:00. I have seen a lot of heat exchangers get holes because the coil above the furnace has frozen and water leaking on the heat exchanger causes it to corrode and get holes and or cracked. I usually would look for signs of water marks
I started up an OXBOX gas pack a few weeks ago and converted it to propane. The ports on the valve were much smaller than anything that I have seen before. I had a cone adapter that worked but I had to hold it in. The barbed adapters that you are showing are way to big to fit the OXBOX valve ports. I assume this tiny port size is normal in China.
what conditions would result if those 'spuds' were the wrong size? ie, a propane furnace was connected to a natural gas supply?
Hi. Do you know a standalone instrument that can measure the pressure inside a hyperbaric chamber in ATA or psi. Is there a wrist worn unit that can do this. Thanks for your help.
30 years in the hvac trade. Have never set gas pressure. but then I don't do start ups. Maybe checked gas pressure a dozen times in 30 years. I am still learning.
Checking gas pressure should be a part of any general service on a furnace. Guess you didn’t work off of a check list.
@@rodgraff1782 If there is no problem why check. Gas pressure. Just a invitation to have a leak and a call back. Besides who needs a check list. Everyone knows checklist are just pencil whipped by technicians. 90 percent of the stuff on check list are not even checked their just jnitiled as being checked. Makes the owners and customer feel good. As far as check list, the company I work for has a check list on our PM tasking. Its normally 3 to 8 inches thick. If you were to actually check what they wanted you to check you would be at the site for 3 months. We are usually there a month, every day all day. We do large scale industial buildings 100 ton chiller, air driers, boilers and Make up units the size of box cars. Fan blades that weigh 300 lbs. It's heavy duty work. Check list and paper work is why I am retiring asap. The work is ok, but the nickpic paperwork is BS. No decent Tech needs a Check list.
@@johnd4348 Just an invitation to get a gas leak?? Any competent tech should be able to remove, and install a 1/8 pipe plug, and not leave with a gas leak. Your analogy is a poor excuse for not taking a reading. Not checking gas pressure, temperature rise, etc, on start ups, is just plain laziness, or incompetence, take your pick. I guess you have never had to go to court. Documentation on start up provides a baseline for future service calls. It verifies that the system was working and running within specs at the time of start up. If you don’t have a baseline, how do you know a piece of equipment was ever running correctly?? I have been hired as an expert whiteness for wrongful death depositions, where an HVAC tech was sued for incompetence. The proper documentation of the service calls and start up records saved his and his companies ass. Otherwise, the business, and the techs career would have been history. BTW. I was a Union HVAC service Forman for 35 years, and also a HVAC instructor for 34 years. I have worked on everything from the smallest residential to the largest industrial chillers, boilers and cooling towers. Not my first rodeo.
@@rodgraff1782 Any good Lawyer can take that checklist and data you gather and turn it against you in a court of law. As far as start up sheets , what technician has that info on future service calls. Union HVAC foreman tells me a lot about you has a technician. A lot of sitting around drinking coffee and telling everyone how it should be done with out ever doing it. Sounds like a person I would never work for. They get their nose out of joint too easily, cant take advise or objective critism. You sound like a very angry guy. Just chill out. It's just HVAC. What you do or how many service call you have done will never be written in any history book or even remember . This trade is Just a bowel of soup. If your puzzled by that last statement ,think about it.
@@johnd4348 obviously you don’t know what you are talking about. One of the reasons I retired at 52, is that even though I was the Forman, I was still doing crawl jobs, not sitting around telling people what to do. Typical scabs attitude about the Union. I was a working Forman, and did dirty jobs, like oil furnace service, because no one else wanted to learn. You have a poor additive about the trade, and work. You wouldn’t last a day working with me. Best thing you could do is retire.
Trane commercial units, the older 25 tons do have negative pressure gas valves, I know that's not what you were getting at... good video!
The pre mix burners on the voyager models
Adjusted may of these. There is. Large red tag on the gas line warning not to set the gas pressure to a positive pressure. This is because the valve is on the suction side of the power burner.
Any gas pressure adjustment made, should be verified by clocking the gas meter, to confirm that the BTU input listed on the equipment nameplate is not being exceeded. To do this, you need to determine the gases heat value per cubic foot from the gas company. If you don’t know, you can use 1050 BTU per cubic foot. Then determine how many cubic feet you are burning per hour, by clocking the meter and multiplying by the heat value of the gas. This will verify that the proper offices are installed in the furnace also.
👍🏻
In our industry an analog clock is an important teaching tool. When you watch the cocks second hand it points to numbers in an increasing pattern. 1, 2, 3, 4, etc,.
In adjusting gas valves or txv’s it works like the clock. Clockwise gas pressure or super heat increase. Counter clockwise gas pressure or super heat decrease.
Came across 2 Lochinavr boilers last week that heat an outdoor pool on the roof of a high rise, they've been "running" for 4 years now, both were out on flame failure, the inlet gas pressure was at least 32" w.c. (my gauge pegs at that point) not sure how they ever ran. Traced out the piping and found no regulator was ever installed, oops LOL
You had better replace those gas controls if they were exposed to pressures over 14”
@@rodgraff1782 yeah no doubt, I informed the custom that getting the gas pressure corrected first was most likely just the beginning
Northern states..many failed secondary htx. obvious signs..sweat socks odor indoors, outdoors, hot upper bulkhead panel, nuisance roll out trips, lack of heat output, brown liquid leaks near inducer fan or in the blower compartment, differential pressure switch trips (lack of htx free flow)..obvious flames do not jet into primary ports..
flame parts outer light blue, and inner core should be darker blue..
Dope on those pressure ports? Yikes
sq inches/ 1000 btuhr input
Whole house exhaust fans create negative atmos in homes..
To properly set gas pressure every gas appliance have to be running at the same time. It does no good to to set with only the furnace running. And never put any pipe dope on the test port plugs. That can stop up the valve.
Not necessary as long as the gas supply piping is sized per code.
@@rodgraff1782 , you are correct. Running all the appliances and taking pressures ( at the meter and farthest fuel run) is how we determine whether the fuel runs are under sized. Tim, as long as proper pressure is going to the Appliance on the supply side ( in manufacturers range) there is no need to run all the appliances. Regulators are designed to stay constant on the downstream side even though the inlet side is varying in pressures. That is the ultimate design of all regulators.
It is another inappropriate term, that plug that actually doesn’t come out is called a boss.
Cough, cough. oops, sorry. Im off for isolation..yep..the one who takes no chances..
I'll be THAT guy. There might be negative absolute pressure and it may be the reason the universe is accelerating. But yeah not applicable here on earth lol. www.preposterousuniverse.com/blog/2013/11/16/why-does-dark-energy-make-the-universe-accelerate/
My gas pressure reads way too high after I have eat my wife’s pot of beans