Proper way to purge air

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  #41  
Old 11-19-07, 05:49 AM
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Originally Posted by NJ Trooper View Post
If you don't need the unions for future disassembly, you sure could get by much cheaper by using "Repair Couplings", which are basically a pipe to pipe coupler that doesn't have a 'stop' in the middle. You take off the tees, and the section of pipe between, slide the couplings down the pipe ends, cut a new piece of pipe to fit between, then slide the coupling back up and center on the joint and solder.
I wasn't aware of that. I'll probably hook up the basment bathroom rad as a seperate zone in the future.

I was pretty successful. I decided to drain the 1 inch main as there was a drain valve before the inlet to the circulator. It never seemed to completely drain! When it took forever to sweat the pipe, I determined that there must be water that flowed toward the joints when I heated the pipe. When I seperated the fittings, a bunch of water came out. After a bout an hour of getting the remaining water out (along with a bit of cussing), it sweat just perfectly.

After filling back up (real slowly according to Who's procedure ), and purging the main and all the rads, I fired up the furnace. When the furnace came up to the low point setting on the aquastat which is mounted on the coil (not used anymore), the circ came on for a minute then I heard a bang. The circulator stopped! Something must have got dislodged in the system (I was surgically careful to keep anything from getting into the pipe I sweat - even when I detached and started again) and got stuck in the impeller.

Having only a shut-off on the inlet side made it difficult to remove the cartridge. Water kept creeping up from the outlet flange and I had to keep a wet-vac running all the while during the inspection. Whatever it was, must have gotten sucked into the vac. The impeller didn't look like it took a hit. I put it back filled and bled, and all worked.

Now for the payoff. The heat to the last rad is hotter than it's ever been - OH YEAH!

Even the next to the last came up to speed when previously it stopped flowing. Maybe that was a clog that then found it's way to the circ. when the system was drained/filled 2x.

Thanks goes to Troop and Who for links, tips, VERY valuable advice.
 
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  #42  
Old 01-03-08, 09:18 AM
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Proper way to purge air HW Base board

I read the the quotes you guys have on this subject. So I in stalled auto bleeders on 2 of my cold rads. now they get hot, but not rocket hot like the other rads in the house. status weils mc clain boiler , Air tank at 22 Psi, 2 rads shut down, of 15 in a ranch house, Caps on the auto bleeders is on lose. taco pump, mono flow system in a figure 8 style. Please help, need to keep the kids warm. Rory 2008
 
  #43  
Old 01-04-08, 01:30 PM
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Originally Posted by rory2008 View Post
I read the the quotes you guys have on this subject. So I in stalled auto bleeders on 2 of my cold rads. now they get hot, but not rocket hot like the other rads in the house. status weils mc clain boiler , Air tank at 22 Psi, 2 rads shut down, of 15 in a ranch house, Caps on the auto bleeders is on lose. taco pump, mono flow system in a figure 8 style. Please help, need to keep the kids warm. Rory 2008
 
  #44  
Old 01-04-08, 06:03 PM
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Figure 8 style ?

Rory, what is a 'figure 8 style' ?

What is the pressure reading on the gauge at the boiler ?

Measuring the pressure on the tank when it is 'on-line' in the system will not give an accurate indication of the actual air charge in the tank. The system needs to be de-pressurized, or the tank needs to be removed from the system in order to get accurate indication of air charge.

How far are the 'cooler' radiators/baseboards from the 'main line' ?

It's quite possible that you have less flow in the cooler ones than the hot ones... it could possibly be a piping issue, rather than an air issue.
 
  #45  
Old 01-11-08, 07:22 AM
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Proper way to purge

Good morning. Tropper The figure 8 is the way the water lines run in the house. If you were to look at from a top view. The 2 rads that are warm are the last 2 on the return end to the boiler. The distance between the main line in the basement to all and the 2 cold rads is no more then 12 inches. Before the 2 cold rads I have 3 small rads, Thinking there is to many choke tubes in a short line with in 4 ft might be my problem. The #s on the boiler are with the Amtrol Extrol tank vavled off is 25 psi. The Honeywell triple Aquastat Relay type L8124Ac are set at Lo 160 Hi 180 the Diff is at 10. With the tank valved on the PSI is 45 psi. We had warm weather last week sorry I could not repaly quickly thanks Rory
 
  #46  
Old 01-11-08, 04:12 PM
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Something confusing...

Rory, If you have 45 PSI in your system, you've got a problem. There should be a safety relief valve on your boiler that is designed to open at 30 PSI . If the pressure were really 45 PSI , you should have water spewing out that valve! 45 PSI on the boiler is starting to get into danger territory as far as pressure goes.

First, make sure you are reading the gauge correctly, there may be 2 scales on it. One may be PSI, and the other FEET. Check again... 45 FEET = 19 PSI and is not cause for alarm.

If the gauge is really reading that high, it's possible that the gauge is not accurate.

If the gauge IS accurate, then something is wrong with the safety valve, and you need to have that problem remedied ASAP.

You should not run the boiler with the EXTROL tank "valved off" . That tank needs to be 'on-line' when the boiler is running. I'm not sure I understand your explanation of the pressure differences when the tank was "valved on" and "Valved off".

I don't know what you mean by "CHOKE TUBE" ...

If only the radiators CLOSEST to the boiler are hot, it might indicate that your CIRCULATOR PUMP is not functioning.

I believe it's possible that you have multiple problems. My advice is to call a technician to check your system out.
 
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Old 01-15-08, 07:55 AM
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Ok no you were right boiler pressure is 20 psi. I tested the safety valve. It was not holding back water after the test it kept on dripping. So that was changed by Hart & Iliff oil in nj. Choke tubes are AKA mono flow tees. The ciculator pump is running fine. So my next thought was the valves on the rads, the ones that don't crank down. They have 3 hash lines on the knob . Are not working well. I know how to open & close them. The rads are warm on the right side and cold on the left. The boiler techs say they don't have any time to check this out. I'm not giving up on this one. If I need toys aka new tools I'll get em. I have a lot whats one more. Thanks Rory
 
  #48  
Old 01-15-08, 03:30 PM
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Whew! that's better... 20 PSI isn't awfully high... probably just about right for a HOT system. On a cold boiler, it would be less than that, correct ?

I believe that being a monoflo system, you probably have air still trapped in the radiators. You said that you put 'auto-vents' on two of them ? Do they all have a vent of some sort ? That's where you need to start, getting the air out of the rads.

You said that your pressure tank is at 22 PSI ... I mentioned that you need to de-pressurize the system in order to accurately read the tank air charge... how did you do with that ?

I would like to think that when the guys were there to change the relief valve and had the system drained for that, that they checked and adjusted the charge in the expansion tank ?

You might find that temporarily raising the system pressure up to 25-27 PSI (just short of your relief valve opening) will greatly aid in the removal of the air. Return the pressure to the normal setting when you are through bleeding.
 
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Old 01-16-08, 06:38 AM
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The boiler techs recharged the pressure tank 20 psi and checked on the draft as per wife. So to depressurize the system pressure. Tell me the way it should be done. I have manaul bleeders on all the radiators. The 2 cold radiators have a 1 inch nipple with a tee fitting holding the auto vent and the manaul bleeder .Should I do this to all the radiators. Trooper doe's it matter what side the valves are on. on the radiators, in mono flow system. On 1 loop of the figure 8 they are in front of the hot feed water. Then next is the mono flow tee. On the larger loop of the figure 8 the valves switch around on the radiators. Whats the name on these valves? Thanks Rory. Gotta replace the motor on the dryer with new belts & pullies.
 
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Old 01-16-08, 09:16 AM
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I would leave it at 20 psi. You can either bleed just the rads that aren't heating, or bleed them all just in case.

Right after a heating cycle when everything is good and warm, shut off the boiler and pump and note the pressure when it is hot.

Then bleed everything in order, first rad first.

If you start to bleed and just get a couple of drips of water - stop and tighten or you'll lose some pressure. When bleeding rads that have air, sometimes you have to close it for a while once the first water comes out and then maybe 30 seconds later see if there is more air. Once you are all done, check to see what the pressure is - has it dropped more than 5 to 8 psi from when you shut the boiler off? It may if there are a few air-bound branches, if so you'll need some makeup water. Don't forget to switch the boiler back on... that's something I'd do.
 

Last edited by NJT; 01-19-08 at 08:43 AM.
  #51  
Old 01-16-08, 06:31 PM
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I agree with Who (aka Mr. Monoflo) about leaving the pressure alone... no need to depressurize if you are confident that they did that. If you had a problem with the tank pressure, you would see large pressure swings from cold to hot boiler. If you are only seeing a few PSI change, then leave it be for now.

The air bleeds on the rads should be near the top ... unless they were originally steam rads ... then they might not have any ... are there any plugged holes near the top of the rads ?

I just scanned back on the previous posts... are we talking about standing cast iron radiators ? or fin tube convector cabinets ? or fin tube or cast iron baseboards ? I was assuming that you meant standing rads ...

Can you take some pics of the rads and post them on a free www.photobucket.com account and provide a link here ? It really helps to see what we're dealing with ...
 
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Old 01-19-08, 07:41 AM
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pictures of the system

here are so pictures guys.

http://s259.photobucket.com/albums/hh291/rory2008/


copy and paste.
 
  #53  
Old 01-19-08, 09:01 AM
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I think I understand what you mean by 'figure 8' now...

You mean that the supply water comes out into that fancy tee, splits and goes two directions toward two separate loops of what appear to be cast iron baseboards. Then, they join at some point, and return to the boiler, creating what you are calling a figure 8 ...

I would just call that 2 parallel loops ... but that's just semantics.

Generally, the air vents will work best if they are on the downstream side of the radiator, at a point where the piping turns down to go back through the floor. That's where the water will collect when the pump is running, so those may be best bled with the pump running.

If some of the rads have the bleeders on the upstream side, you may not get anything but water out of them ever... but put a level on the rads, if they happen to slope up toward the bleeder, leave the system off for a while, and bleed those with the pump NOT running.

In any case, temporarily increasing the system pressure may help bleeding because the air bubbles are compressed and may move more easily being smaller... If any of those rads are BELOW (I didn't see any in the pics) the distribution piping it will help to bleed those when the system is cold.

By the way, if you get nothing but a stream of water out of the air vent, no sense in going any further... (as in that one pic with the plastic pail), you want air ... if it's MIXED with air, (I think Who said this) close the bleeder, wait a while and try again in a few minutes.

I'm not real certain about those valves, whether the handle can be installed two ways or not, but they are quarter turn valves? and I believe they are called PLUG VALVES ? If they can be installed with the handle in only one position, I _THINK_ (definitely verify this, cuz I ain't sure), that the 'hash' marks are parallel to the pipe when the valve is OPEN ... Do those valve turn 360* all the way around ? or is there a stop that only allows 1/4 turn ?

Grady, where are you ? yoo hoo ... can you shed some light on them valves ? Ken ? furd ?
 
  #54  
Old 01-22-08, 06:12 AM
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Trooper I checked with a level and found 1 cold rad dead level. And the other 3/8" off. I have to relocate or add manaul bleeders to the rads, See photos 3 & 5 they don't have bleeders. So this is my attack plan. Shut the system off. Turn the feed water off, lower the pressure on the expanion tank, bleed the 2 cold rads, install bleeders with auto vents, Then back track my work. keep the boiler off over pressurize the expanion tank to 25 - 28 psi and bleed the rads while they are cold. so the air bubbles don't heated up and go into solation and get small. Close the valve on the rads. so the water will follow the path of lest restantance. The valves, some have a pin in the knob to give it a 1/4 turn and the other valves turn 360* with out the pin. Sory I Had to watch foot ball my only day off. I will keep you posted. Thanks Rory
 
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Old 01-22-08, 04:01 PM
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Rory, I don't want you to change the pressure on the EXPANSION TANK ! Once the proper air charge of 12-15 PSI is on the air side of that tank, leave it be.

I was talking about the pressure in the BOILER.

Read again before you do anything...
 
  #56  
Old 01-23-08, 05:43 AM
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Trooper I have not touched anything yet. So to raise the system pressure on the boiler is done how. With well water feeding the boiler, That pressure can only go so high. In photo 10 there is a device that goe's from the house water side to the boiler side it's gold and has a red handle gate valve next to it. What's its name, And it's job. I will work on the system on Saturday. It's hard to work with a 1 yr & 3 yr old grabbing your tools. and mommy works nights. so I'm not rushing. Thanks Rory
 
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Old 01-23-08, 05:38 PM
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I know what you mean about the young'uns ... none of my own around here, but I always get 'visitors' from next door whenever I poke my head outside and try to get any work done in the yard.

That gold device is called by several names:

'pressure reducing valve'
'auto fill valve'

are probably the most common.

The handle on it is called the 'fast fill' , if you lift that up, the 'pressure reducing' part of the valve is bypassed, and will allow you to increase the pressure in the boiler. (up to the max that your water system will deliver, but that's probably more than the 30 PSI that your 'pressure relief valve' is set at)

The red handle valve is actually a 'ball valve', not a gate valve. You only need to close this valve if you intend to decrease the pressure in the boiler _below_ what the 'pressure reducing valve' is set to maintain.

To decrease the pressure in the boiler, you would use a drain hose or a bucket at any of the hose bibs. Letting water out of any one of them will reduce the pressure. (as above, if the red handle valve is open, you won't be able to reduce below the setting on the 'pressure reducing valve' .

By the way, being on a private well system, you might consider as a future upgrade adding a 'backflow preventer' in line with the 'pressure reducing valve' and the red handle shut-off valve. You don't want boiler water going backward into your domestic water system in the event that the boiler pressure is higher than the water system pressure. On my well system this happens on occasion... for example, the pressure switch on my well pump is set at 20 - 40 ... so the pressure in the domestic water will drop to 20 before the pump kicks on ... at times, it's possible for the pressure in my boiler to be slightly above 20 ... without a backflow preventer, it's possible that the boiler water could travel back into my home water system . Don't want that !
Something to think about...
 
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Old 01-29-08, 05:26 AM
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Trooper I worked on the boiler sunday & monday. I boosted the system pressure to 24 psi and bleed the rads after a heating cycle with the boiler & pump turned off. Now I have an even heat going the hole length of the rads. But not real hot. I have the system psi and the expantion tank psi reset at 15 psi. I think its time for the plumber. Rory
 
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