Proper way to purge air


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Old 10-30-07, 05:43 AM
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Proper way to purge air

I have a monoflow system with a drain valve/gate valve combination pair installed on the main line as well as one of the return lines of one convector. Can someone tell me the proper method to purge air from the system. I never seem to get the air out of the system. I do not have a bladder type expansion tank. I have instead a tank horizontally mounted in the basement ceiling that I think may not be doing anything. I can always hear the bubbles trickle through the lines and would like some advice on how to get rid of it. Also the drain valve/gate valve pair on the return line of one of the convectors is the last convector on the run. It was installed because that convector never gets as hot as the others. Maybe there's another reason. Maybe I need to replace it. I shut down the convector that's upstream of it to allow the last one to get a little hotter, but it doesn't work. Maybe it's partially blocked. It's vintage 1955.

Thanks in advance,

Al
 
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Old 10-30-07, 07:01 AM
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Seriously consider ditching the old tank and getting a bladder tank. Monoflo systems give air from that tank way too many places to go hide/visit. Air in the old style tanks can and will go into solution and then come out of solution in a heating branch where you don't want it. That said...

Boiler off...

Shut you autofeed valve off.

Isolate your expansion tank and then drain it completely... every single drop.

Turn your autofeed valve on.

Slowly, really slowly open up the valve leading to the expansion tank.

Next, boost the pressure in the system to about 25 psi.

Now go around in the direction of the flow and bleed each branch. If you get a ton of air out, boost the pressure back up to 25 psi until you are almost done when you'll want the pressure to be around 15 psi.

Once all the air is bled, turn the heat on. Rebleed as needed.

Sure as Shirley, you'll be doing this once or twice a year until you get rid of that tank.

----- ----- ----- ----- -----

What I'd do... Buy a properly sized expansion tank and an autovent valve. The ET-30s are a common size for most homes, but you should still size it. Extrol and Watts both online sizing tools.

You can simply tee off the pipe going up to the old tank and put an autovent at the top of the vertical riser. It will get rid of any air in the system - except the air you want that stays behind the rubber bladder where it can't go wandering to your Monofol branches).

From the tee, extend horizontally a short jog (basically just over the radius of the expansion tank) in 3/4" size leading to a 3/4" to 1/2" reducing elbow, drop some 1/2" pipe down to closer to the floor so that the bladder isn't getting as big of heat swings and then place a 1/2" ball valve near the bottom. Ensure your new tank is pressurized to 15 psi (unless your house is 3 storeys or crazy tall) and then hang it below the ball valve.
 
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Old 10-30-07, 08:06 AM
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Bleeding air from monoflow

Wow Who, that was a lot - thanks!

Question:

Autofeed valve. That's the valve that feeds the expansion tank or is it the valve that supplies the whole system? There is a seperate pipe and valve that feed the tank and one that supplies my boiler.

Are the shutoff/drain valve there to serve a purpose? Earlier I said that one was installed in the return line of one of the convectors which happens to be the end of the run. Can some air be bled from that unit or can it be only be bled using the No 67 vent at the top of the little tank?

Thanks again.

Al
 
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Old 10-30-07, 08:44 AM
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Autofeed is the PRV (pressure reducing valve) and anti backflow valve that adds water to your heating system from your domestic rinking water supply - not all systems have this.

No 67 on the top of what little tank? On top of the expansion tank? If so can you better describe your expansion tank?

As for bleeding, drain the isolated expansion tank (if it isn't a bladder type) and then get pressure back (plus some extra helps get rid of teh air) and then bleed each branch. At the end of each rad there should be a bleeder.
 
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Old 10-30-07, 01:19 PM
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Originally Posted by Who View Post
Autofeed is the PRV (pressure reducing valve) and anti backflow valve that adds water to your heating system from your domestic rinking water supply - not all systems have this.

No 67 on the top of what little tank? On top of the expansion tank? If so can you better describe your expansion tank?

As for bleeding, drain the isolated expansion tank (if it isn't a bladder type) and then get pressure back (plus some extra helps get rid of teh air) and then bleed each branch. At the end of each rad there should be a bleeder.
The expansion tank has no bleeder on it. I was referring to the No. 67 air vent on the tank (that's what I call it) on the downstream side of the convector. I use that to purge any air that may be in the convector, though there seldom is any air that comes from the convector. The convector looks to me like a car radiator. That is, a set of three tubes with metallic plates that surround the group and flanked with a pair of tanks. Sort of like modern baseboard but in triplicate.The upstream tank has a valve that can be quarter turned to open or close it to the flow. The downstream tank has an air vent. Sorry that I wasn't clearer. The whole unit is inside of a box that has a removeable grilled cover that is half recessed into the wall. Throws out a bunch of heat so I didn't replace the ones that were in remodeled rooms.
 
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Old 10-30-07, 04:04 PM
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Al, do you keep the cap on that 67 autovent open or closed when in normal operation ? I don't believe that's a proper application for that part. Your system should really not have any autovents on it. It could under certain circumstances actually draw air INTO the system.

Also, the air that Who was talking about going into solution in the water from the air in the expansion tank eventually needs to go back to the expansion tank. If it gets vented from the autovent, eventually what happens is that the air in the tank is depleted and it becomes waterlogged. You need to let that air go back to the tank.

There's nothing wrong with a small manual bleeder in that location, either that, or keep that cap screwed down tight when the system is in operation.

You problem could be a deficiency in the way the way your system is piped. Perhaps in such a way that the air in the system isn't easily caught and sent to the expansion tank, where it belongs.

As for the last convector not getting as hot as the others... it probably won't because being on the end of the line, the water entering it is cooler by the time it gets there. How many other emitters (convectors/baseboards,etc) are ahead of this one ?

Can you post some pics ? I didn't understand the 'drain valve/gate valve combination' you spoke of.
check out photobucket.com for posting pics and provide a link here.
 
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Old 11-05-07, 04:35 AM
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Originally Posted by NJ Trooper View Post
Al, do you keep the cap on that 67 autovent open or closed when in normal operation ?
Yes I keep the cap on tightly which I originally thought was defeating the whole premise of being an "auto" vent

You need to let that air go back to the tank.
OK How?

There's nothing wrong with a small manual bleeder in that location, either that, or keep that cap screwed down tight when the system is in operation.
Bleeder is only on each convector, capped tightly.

As for the last convector not getting as hot as the others... it probably won't because being on the end of the line, the water entering it is cooler by the time it gets there. How many other emitters (convectors/baseboards,etc) are ahead of this one ?
There are nine total. I shut the valve that feeds the next to the last so as to give up it's energy to the last. That didn't seem too effective either.


Can you post some pics ?
Working on it. Link is coming when I upload pics.

I didn't understand the 'drain valve/gate valve combination' you spoke of.
Sorry. The best way to describe it is in one application, the return pipe in the mono-flo which is on the intake side of the Taco circ. has a shut-off ball valve which is followed by a drain valve. On another use, the return pipe which is from the outlet of the last convector has a similar pair of valves. If that don't work, then pictures may better illustrate.
 
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Old 11-05-07, 04:34 PM
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Originally Posted by Al S View Post
Yes I keep the cap on tightly which I originally thought was defeating the whole premise of being an "auto" vent
Yeah, it kinda is, but since that's not really the correct application for the auto-vent, you need to defeat it's purpose ON purpose ! If you had a bladder type expansion tank on this system, you would be fine to let that 67 do it's thing with the cap left loose.

Originally Posted by Al S View Post
OK How?
Just leave it be... air that is traveling through the system should eventually be caught by your air separator and will automatically go to the expansion tank. (this is assuming that you have a correctly piped separator and the tank is piped off of that.)

Originally Posted by Al S View Post
Bleeder is only on each convector, capped tightly.
Good, use those to bleed any air that is trapped in each convector.

Originally Posted by Al S View Post
There are nine total. I shut the valve that feeds the next to the last so as to give up it's energy to the last. That didn't seem too effective either.
As an experiment, try shutting more (even ALL) of the upstream rads to force as much hot water as you can through the last one, and see if you get more heat out of that one.

If you have or can borrow an infrared thermometer, try measuring the in and out temps on each convector.

With nine convectors on the loop, you may find that by the time the water reaches the end, it's just too cool to get any heat out of.

Did you say this is a ONE PIPE monoflo system ?

Originally Posted by Al S View Post
Sorry. The best way to describe it is in one application, the return pipe in the mono-flo which is on the intake side of the Taco circ. has a shut-off ball valve which is followed by a drain valve. On another use, the return pipe which is from the outlet of the last convector has a similar pair of valves. If that don't work, then pictures may better illustrate.
That sounds like a "purge station". By connecting a hose to the drain and closing the inline valve, one can force water through the loops to purge trapped air.

Pics will help a lot for that... just to be sure that's what it is.
 
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Old 11-05-07, 04:38 PM
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couple more questions...

Al, what's the pressure reading on the boiler gauge , both cold and hot ?

Have you drained the expansion tank ?
 
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Old 11-06-07, 10:33 AM
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Originally Posted by NJ Trooper View Post
Good, use those to bleed any air that is trapped in each convector.
I used the procedure outlined by Who and get no air in system

As an experiment, try shutting more (even ALL) of the upstream rads to force as much hot water as you can through the last one, and see if you get more heat out of that one.
I'll try that.

If you have or can borrow an infrared thermometer, try measuring the in and out temps on each convector.
Pffft. Sure! Where can I borrow one? I would love to have one to do one of those energy surveys for the home. They're not cheap though. I see the ones from Omega Engineering and they can be steep

With nine convectors on the loop, you may find that by the time the water reaches the end, it's just too cool to get any heat out of.
High side aquastat is 180, low side 160.

Did you say this is a ONE PIPE monoflo system ?
Yes. As shown in pics.


That sounds like a "purge station". By connecting a hose to the drain and closing the inline valve, one can force water through the loops to purge trapped air.
Does circ. pump need to be running? Brief procedure?

Pics will help a lot for that... just to be sure that's what it is.
Link posted below. Thank you for your help so far!
http://picasaweb.google.com/eastlocust/BoilerAndHeater
 
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Old 11-06-07, 11:16 AM
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Al, it's getting hard to follow -- what's the current status?

A. Is the air all purged?

B. Is the system heating evenly?

If you have A but not B then you have to think about the circulator. On a monoflo system a certain flow rate is required to force heated water down the side branches. If the impellor is old or worn out then flow will be reduced.
 
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Old 11-06-07, 11:25 AM
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Originally Posted by Who View Post
Al, it's getting hard to follow -- what's the current status?

A. Is the air all purged?

B. Is the system heating evenly?
No and No.

If you have A but not B then you have to think about the circulator. On a monoflo system a certain flow rate is required to force heated water down the side branches. If the impellor is old or worn out then flow will be reduced.
If you refer to the link in previous posting, there are pics of my system. One of the pics shows a Taco circ. which replaced a B&G. BTW I followed your purge procedure. I turned off both the feed to the system, and the feed to the expansion tank. I drained the expansion tank, barely cracked open the valves then checked for air after about a half hour on all convectors after raising pressure to 25 PSI - NO AIR found! I did do this however all the while that the system was off - no burner no circ. Did I miss a step? I would think that there would have been air present. Looking at the pics, could I place the bladder expansion tank in place of the old one? I saw that ideally it should be placed after water leaves the boiler, with the flow valve just after that.
 
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Old 11-06-07, 11:34 AM
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Okay... what's coming out of the bleeders? Water?
 
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Old 11-06-07, 12:33 PM
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Originally Posted by Who View Post
Okay... what's coming out of the bleeders? Water?
Yes, just water. I really only get air when I am purging at the start of heating season.
 
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Old 11-06-07, 12:40 PM
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Okay, so air isn't an issue anymore... it's purged.

Back to flow... any branches closed off? If so they may be adding enough restriction to the circulation that their isn't enough overall flow to force heat down the branches.

If that's not the issue then we have to consider the circulator. Is it working properly? What shape is the impeller in? If the impeller gets crappy it won't move as much water as it did when new and you'll have heated water following the mains but not heating things up through the branches.
 
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Old 11-06-07, 02:07 PM
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Originally Posted by Who View Post
Okay, so air isn't an issue anymore... it's purged.
I guess.

Back to flow... any branches closed off? If so they may be adding enough restriction to the circulation that their isn't enough overall flow to force heat down the branches.
From my original post, I thought that air was the culprit for not having the last convector on the run not get hot enough. I then shut down the next to the last unit so to allow extra heat to the last unit. It's not really a serial system is it? I mean, the unit is fed by a 'tee' - one with a baffel that allows water to go one way. The other is there as a collector for the return and mixes with the water that bypasses it - refer to pics.

If that's not the issue then we have to consider the circulator. Is it working properly? What shape is the impeller in? If the impeller gets crappy it won't move as much water as it did when new and you'll have heated water following the mains but not heating things up through the branches.
Taco circulator is three years old. It replaced a big red B&G. The reason for replacement was that the coupling was REAL noisy! It sounded like there were marbles in the pipes. The heat issue was before and after the changing of the circ.
 
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Old 11-06-07, 03:52 PM
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Originally Posted by Al S View Post
Pffft. Sure! Where can I borrow one? I would love to have one to do one of those energy surveys for the home. They're not cheap though. I see the ones from Omega Engineering and they can be steep
I think you are thinking of those infrared scanner camera thingies... no, what I'm talking about is a small handheld gun with a laser pointer on it that you can remotely measure temps. They aren't _that_ pricey I didn't think... maybe they went up ? why not, everything else did !

Originally Posted by Al S View Post
High side aquastat is 180, low side 160.
I'm assuming that this means that you have a domestic hot water coil in the boiler also ?

You could get a few more BTUs outta the convectors by bumping up to 190 on the high setting. And if indeed you are using a tankless coil in the boiler for domestic hot water, start turning the LOW setting down say 5* every day or two until you or your housemates start complaining about cold showers then bump it back up to the previous setting.

Originally Posted by Al S View Post
Yes. As shown in pics.
Going to look now...
 
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Old 11-06-07, 04:16 PM
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Al, I'd like to see some wider angle shots so I can get an idea how the whole thing fits together. But, the shut-off and drain combination could be called a 'purge station'. These valves would be used in combination with other valves in order to direct water flow through certain parts of the system. Generally only used during initial filling, and after service work which required draining the system. They wouldn't be used for normal bleeding operations.

The pic showing the bleeder on the convector end tank: It appears that there is gray paint obstructing air flow through the convector fins ? If so, that will most definitely reduce the BTU output of the convector if the blockage is substantial. Dust in the fins will also greatly hamper air flow. Is that paint I see ? or just camera trickery ?

I don't see anything else to be concerned with, unless that rust staining on the surface behind the circulator is evidence of a leak that hasn't been repaired.

See if you can post a few shots that give a general overview of the piping...
 
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Old 11-06-07, 05:42 PM
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Think of the main a 4 lane single direction highway. Four lanes of heat go through the main pipes. Each monoflo is placed at the end of a bypass lane that forces one of the 4 lanes through the bypass (heating branch / emitter). If you have a monoflo and then also close the branch, you force it down to 3 lanes through that section. The overall flow slows. The thing is you need all 4 lanes so that you can swueeze a lane down each bypass. Block a bypass and then all 3 lanes stay in the main truck and start skipping bypassed... anyway, you have one branch manually closed and if they are all bleeding water, air shouldn't be blocking any of the others.

Okay, so this heat issue was before pumps. Maybe the last branch should have monoflos on both ends?
 
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Old 11-06-07, 06:04 PM
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Originally Posted by Al S View Post
It's not really a serial system is it?
Sure it is ... only way it could be anything but is if there were two or more pipes doing the supply and return.

Who's analogy is a good one, but I like the heat train better ...

Think of the water as a train carrying passengers (heat, BTUs) and each convector as a station. At each station some passengers get off and the train continues on it's way. By the time it gets to the last station, there are no more passengers on the train... cold convector.

The system appears to be piped in 3/4" copper... so with a 'normal' design, flowing 4 GPM (standard), you can carry 40000 passenger BTUs. You've got nine stations, let's say that 5000 passengers get off at each stop. By the time you get to the 9th station, there just ain't no mo ...

Depending on the size and BTU rating of those convectors, you might have even more BTU per convector. Your best solution might end up being to split that loop into two parallel loops, one with 4 and one with 5 .
 
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Old 11-06-07, 06:30 PM
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Trooper, don't forget that a monoflo system is a low ΔT, high flow method. From your train analogy, it has about 20 cars on it and only has to dump off one car at 12 different sidings. It's the nature of the beast and fine for oil. I live a monoflo life here... damn I wish I had home-runned TRVd panels! Ummm Santa???
 
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Old 11-06-07, 07:17 PM
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ΔT and flow aside, you should still only be pumping 4-5 GPM max through a 3/4" pipe. (in the pics anyhow, it looks like 3/4, but it's hard to judge from a pic sometimes). And with 4-5 GPM of flow, that means 40-50 KBTU . If the convectors are rated a 5 KBTU each (which is probably a low estimate), there just won't be enough heat left in the water at the end of the run !

I know that you know that those monoflo tees add a very substantial amount of head to the piping. By the time you figure in 9 monoflos, yer lookin' at what, 200' Total Equivalent Length of pipe ? Aren't they like 20' EACH ?

Between the extra head on those monoflos, and the fact that there are 9 convectors on the loop, I'd be surprised that the last one isn't sucking heat OUT of the room ! (THAT'S A JOKE!... JUST KIDDING!) but you see my point ?

I just betcha there's a 40* ΔT on that system...
 
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Old 11-06-07, 08:04 PM
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If the monoflo has been hacked to feed a 0.75" line then that's your issue. If it's 1.25 for the mains, run a bypass in an inch to be safe with a valve to restrict flow if needed to still heat the 0.75" line that is now a bypass. If the main is 1" then 3/4" bypass would work. If funds are tight then I'd do the bypass in 3/4" regardless. You could probably run 2 3/4" lines cheaper than 1". You only need type M copper.

Jeff, monoflo being high head just doesn't make sense and I don't know why it gets repeated. I have a 1.25" monoflo system. It needs to flow about 10 - 12 gpm for water to go fast enough for the venturis to actually work. It falls apart on a 15-58 on speed 1 (7 gpm?). It it were high head then the gpms would be low and the ΔT would be high but that's a common misunderstanding. Remember I have a super low ΔT on my system and a modcon using just its own internal 15-58 on speed 2 to go through 15 monoflos, a 1" P/S bypass section and some 1" near boiler. In fact it's because they are low head systems that any significant reduction in flow causes the venturis to fail and result in uneven sporadic heating.

Bypassing a 3/4" line seems the best way out of this. Pipe it so that there are no air traps and with a valve in case you ever need to tune it.
 
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Old 11-06-07, 08:39 PM
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Actually the one monoflo that's there appears to be on a 1" main line, with 1/2" to the convector.

Al, what size pipe is the main line ?
 
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Old 11-07-07, 04:24 AM
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Originally Posted by NJ Trooper View Post
I think you are thinking of those infrared scanner camera thingies... no, what I'm talking about is a small handheld gun with a laser pointer on it that you can remotely measure temps. They aren't _that_ pricey I didn't think... maybe they went up ? why not, everything else did !
No I know about the camera versions they are about a couple of K$. I also know the one you're talking about. I saw Alton Brown use that to measure the temp of a frying pan. It looks like a pistol with a digital display on the back facing the user.


I'm assuming that this means that you have a domestic hot water coil in the boiler also ?
No! Capped off and using seperate gas HWH.
 
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Old 11-07-07, 04:27 AM
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Originally Posted by NJ Trooper View Post
Actually the one monoflo that's there appears to be on a 1" main line, with 1/2" to the convector.

Al, what size pipe is the main line ?
Correct as observed. Main is 1" that runs around the basement with the two tees on each branch feeding 1/2"
 
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Old 11-07-07, 04:42 AM
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Originally Posted by NJ Trooper View Post
Al, I'd like to see some wider angle shots so I can get an idea how the whole thing fits together. But, the shut-off and drain combination could be called a 'purge station'. These valves would be used in combination with other valves in order to direct water flow through certain parts of the system. Generally only used during initial filling, and after service work which required draining the system. They wouldn't be used for normal bleeding operations.
OK.

Is that paint I see ? or just camera trickery ?
It's paint.

I don't see anything else to be concerned with, unless that rust staining on the surface behind the circulator is evidence of a leak that hasn't been repaired.
The flue is out view. During a big rain, water gets behind the foundation and finds it's way to the joint of the flue and the chimney[/quote]

See if you can post a few shots that give a general overview of the piping...
Will do!
 
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Old 11-07-07, 04:55 AM
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Originally Posted by NJ Trooper View Post
The system appears to be piped in 3/4" copper... so with a 'normal' design, flowing 4 GPM (standard), you can carry 40000 passenger BTUs. You've got nine stations, let's say that 5000 passengers get off at each stop. By the time you get to the 9th station, there just ain't no mo ...

Depending on the size and BTU rating of those convectors, you might have even more BTU per convector. Your best solution might end up being to split that loop into two parallel loops, one with 4 and one with 5 .
It's definitely 1". Does splitting the system require an additional zone with another circ.? Can it be just divided down the middle from number 4 or number 5 or does it need more thought as to the BTU use of each?
 
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Old 11-07-07, 03:31 PM
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Originally Posted by Al S View Post
No! Capped off and using seperate gas HWH.
In that case, you might want to drop the LOW setting on that aquastat as low as it will go, because you will still be keeping the boiler hot for the past use of the domestic coil. Before you do that though, which aquastat is on there ? The other option would be to convert to a 'cold start' and change out the aquastat.

Originally Posted by Al S View Post
It's definitely 1". Does splitting the system require an additional zone with another circ.? Can it be just divided down the middle from number 4 or number 5 or does it need more thought as to the BTU use of each?
If it's 1", there really shouldn't be need to split I don't think, there must be another reason for the low heat out of the last convector. If you were to split the loop, you could feed both series loops in parallel, and not need another circ. You would need to keep the flow in the same direction for the monoflos to work properly, so you would install a TEE at the start of the loop, run a 1" line to where you break the loop, and feed the second half at that point, in the same direction. Then, run the return side of the other half back to the return of the boiler and tee into the return after the last convector. But that academic at this point, since 1" should be fine in your application. I'm wondering though if a bigger pump might not be on the ticket.

Any idea what the ΔT is ? (the difference between supply and return ?)

You may have already told us this, but I'll ask anyway:
Each convector has a monoflow on the supply side, and a standard tee on the return ?

That paint on the fins, is it blocking a significant portion of the fins ? and is that the one with the troubles ? You might want to spend some quality time on your knees with a sharp knife attempting to open that up so air can flow ... sounds like fun, don't it ?
 
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Old 11-12-07, 07:14 AM
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Originally Posted by NJ Trooper View Post
In that case, you might want to drop the LOW setting on that aquastat as low as it will go, because you will still be keeping the boiler hot for the past use of the domestic coil. Before you do that though, which aquastat is on there ? The other option would be to convert to a 'cold start' and change out the aquastat.
When I drop the setting on the low side, all it does is allow the circulator to spin when the thermostat call for heat. Turning it up to lets say 140 will spin the circ for about 30 seconds or so. When the temperature detected is less than that, the circ. will shut down until the temperature is at a minimum 140 It is mounted in the area occupied by the coil though that's not used any more. It is a Honeywell type and I'll try and get a model number if possible. What is a 'cold start'?


I'm wondering though if a bigger pump might not be on the ticket.
Such as?

Any idea what the ΔT is ? (the difference between supply and return ?)
I have a digital probe thermomter that I can utilize for this test. I'll try and make as close of a contact to the copper as will allow an accurate reading

You may have already told us this, but I'll ask anyway:
Each convector has a monoflow on the supply side, and a standard tee on the return ?

That paint on the fins, is it blocking a significant portion of the fins ? and is that the one with the troubles ?
No. Actually, that one is totally cold now. It is located one unit upstream of the origianl problem unit. I wonder if there may be a clog as I can not get that warm anymore.
 
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Old 11-12-07, 08:38 AM
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Each convector has a monoflow on the supply side, and a standard tee on the return?
Typically the diverter tee is where the branch ends not starts.

http://www.heatinghelp.com/heating_howcome3.cfm
 
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Old 11-12-07, 10:09 AM
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Originally Posted by Who View Post
Typically the diverter tee is where the branch ends not starts.

http://www.heatinghelp.com/heating_howcome3.cfm
Yes, and fed through a 1 inch pipe for the mono-flo.
 
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Old 11-12-07, 10:35 AM
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Originally Posted by Who View Post
Typically the diverter tee is where the branch ends not starts.

http://www.heatinghelp.com/heating_howcome3.cfm
I think I may have found a cause. I read the info on the attached link. I have to check on something tonite. That is some site!!!
 
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Old 11-12-07, 03:00 PM
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Originally Posted by Al S View Post
No! Capped off and using seperate gas HWH.

Al, I recently learned that at least one major manufacturer CAUTIONS! about capping an un-used tankless coil. They mention property damage and loss of life in their statement!

I assume the reason for this is that the coil can build internal pressure and BLOW!

Personally, I would heed the warning and open the coil to atmospheric pressure. I wouldn't do this when the boiler was hot! I'd let it get cold and drill a hole in one of the caps.

Converting to cold start may not be advisable. I understand that it can cause a boiler that has lived it's life as warm start to sprout leaks.
 
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Originally Posted by NJ Trooper View Post
Al, I recently learned that at least one major manufacturer CAUTIONS! about capping an un-used tankless coil. They mention property damage and loss of life in their statement!

I.
I wanted to cap the coil in my old VanVert multifuel, and was warned not to do it... I ended up removing off the copper coil and plugging the inlet/outlet ports.

Pete
 
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Old 11-13-07, 04:40 AM
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Originally Posted by NJ Trooper View Post
Personally, I would heed the warning and open the coil to atmospheric pressure. I wouldn't do this when the boiler was hot! I'd let it get cold and drill a hole in one of the caps.
Removed both caps - Done! Some steam came out later from pipe stubs when heater came up again, but no issues.

Converting to cold start may not be advisable. I understand that it can cause a boiler that has lived it's life as warm start to sprout leaks.
I know that a friend of mine used to shut off his boiler in the summer time. When he saw a big puddle of water on his floor, he stopped that practice. I turn mine down in the summer, but not off. There's way too many deposits in the cavity and in the flue when I turned it off one summer. I never had any of the sections leak though.

I found something that may interest all that have been so helpful. I said that my diverter tees were on the return side. I thought the flow was in a different direction. The diverter tees are ALL on the supply side! I visited the site that Who attached and it revealed a potential other problem. Previously I had a convector that was located in the level of the boiler. That is, there was two diverters to feed a lower level heater in a basement bathroom. I capped that off to allow the heat energy to the 'last' convector. I think I may have to put a section of 3/4 pipe to allow flow around those two diverter tees. I may have a flow problem according to the web site. The other thing I noticed was the section that talked about the 200 foot length from the main line to feed a heater. While in my case, the distance is only around maybe 10 feet, it is the longest run.
 
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Old 11-13-07, 02:19 PM
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Originally Posted by Al S View Post
... I thought the flow was in a different direction. The diverter tees are ALL on the supply side!...
That in itself shouldn't pose much of a problem really, providing they are facing the correct direction.

Originally Posted by Al S View Post
...I capped that off to allow the heat energy to the 'last' convector. I think I may have to put a section of 3/4 pipe to allow flow around those two diverter tees...
Either that, or just remove the tees altogether, you've gotta drain the loop anyway, get the torch out anyway, get rid of 'em ! You will get quite a bit more flow I am sure. Taking those two tees out will probably look like 60' less pipe to your circ, maybe more! And, with more flow, there will be a greater pressure diff across the existing tees, meaning you will get that much more flow through the other rads.
 
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Old 11-14-07, 04:44 AM
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Originally Posted by NJ Trooper View Post
Either that, or just remove the tees altogether, you've gotta drain the loop anyway, get the torch out anyway, get rid of 'em !
When I capped the ends from the tees that fed the rad, I didn't drain the loop, but that was before heating season. I'll de-solder the tees either way and union the section between them with 1 inch pipe.
 
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Old 11-14-07, 05:04 PM
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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.
 
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Old 11-14-07, 06:30 PM
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Troop, thanks for mentioning repair couplings... never heard of them and could have used them a few times.

Much appreciated!
 
 

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