Certain Radiators not working after partial system water loss

Reply

  #1  
Old 11-10-12, 10:16 AM
Member
Thread Starter
Join Date: Nov 2012
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Certain Radiators not working after partial system water loss

OK, it started because I had to replace and overpressure valve, because I hit it, and then it wouldn't close.

Next I tried to let some pressure off with the lower boiler drain in order to replace op valve and it wouldn't reseal.

So I fixed both of those, new 15 psi op valve, new washer in drain.

Now, at first I didn't have any heat. So I bled the radiators. Got upstairs working right away, downstairs I only got three radiators and they feel a bit weak. Four are not working at all. I have bled and bled, not much air. No idea what is going on.

Boiler was replaced in the early 80's, original radiators, fin and tube, from early 50's.Circuit is in crawl space, so all radiators above.

Oh, in the process, I think the air vent is bad, but the little cap is keeping the trickle of water stopped. I have my suspicions on the air tank as well.

I gotta get this working. Oh, btw, the main temperature setpoint on the boiler is 190, but the temperature guage on the boiler reads 150, but I think this is wrong.

Please
 
Sponsored Links
  #2  
Old 11-10-12, 10:59 AM
Member
Join Date: Aug 2009
Location: USA
Posts: 4,947
Received 0 Votes on 0 Posts
How are you bleeding the radiators? Do they have their own bleeders on them? Replace that air vent. You need it to function.

When say overpressure valve, do you mean the pressure relief valve? The new one is only 15 psi? UIt should be 30 psi.

The aquastat dial could be off as well as the temp gauge. I would get a new gauge.

What kind of expansion tank do you have and why do you think it is a problem? Usually when there is an issue with the expansion tank, your system overpressures and spews water out of the PRV.
 
  #3  
Old 11-10-12, 12:15 PM
Member
Thread Starter
Join Date: Nov 2012
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
I'm sorry, the relief is 30, not 15, and it vented once, made me wonder is the expansion tank was bad. Of course I suppose the press lowering inlet valve could be bad. I keep letting air out, because I can't find a new bleeder locally today, HD and Lowes don't have them in stock.

The radiators I keep bleeding, but it isn't helping, no air.
 
  #4  
Old 11-10-12, 12:21 PM
Member
Thread Starter
Join Date: Nov 2012
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
I went in the crawl space, are those taps marked feed and return just taps, or is there a restrictor of some sort in there. Other than the bleeder on the radiator, all the connections appear to be sweat. I am starting to think 60 years of gunk has plugged some radiators, and some I am going to dig out a torch, so I can unsweat. I wish there had been a drain plug or something.

Don't know what else to do, running out of time, going to be pretty cold tonight.
 
  #5  
Old 11-10-12, 01:19 PM
Member
Join Date: Aug 2009
Location: USA
Posts: 4,947
Received 0 Votes on 0 Posts
Slow down! Your idea of gunk clogging the radiators is craziness. You are only going to make things worse. Take some pictures of what you are talking about and show them to us. Stop panicking. You have air stuck somewhere and we need to get it out.

What does your pressure gauge indicate is the pressure in the system? What temperature as well?
 
  #6  
Old 11-10-12, 01:36 PM
Member
Thread Starter
Join Date: Nov 2012
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Yes, there is a certain level of panic as I have a 5 year old and it is going to be freezing tonight.

I don't at the moment have a digital camera, but the system is 50's, updated to a weil mclain package boiler 66e but the system looks like some others pics recently posted. Only a boiler drain, no shut offs or drains otherwise.

Since the upstairs were bled, they are working. Seem a bit weak. The system pressure seems to hunt between 12 and 20, depends on when the oil burner ran. In the course of replacing the op valve, probably lost about 3 gallons of water.

I can't find any other air purge valve other than the one that is up near the little cushion tank.

I just can't figure out how some of the radiators are working, just enough to keep the house about 50 at night. Havn't been able to get half of the downstairs working.
 
  #7  
Old 11-10-12, 06:56 PM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,493
Received 33 Votes on 25 Posts
When I was five years old the house I grew up in did not have heat in the upstairs bedrooms. Come to think about it, that house didn't have heat upstairs when I sold it after my mother's death and I was 48 years old. I remember many times when we couldn't open the window because it was frozen shut and there was a complete sheet of ice on the inside of the glass.

So trust me, your child will NOT freeze if your house drops to 50 degrees inside. Unless, of course, you make him/her sleep naked with no blanket.

Those "taps" you see in the crawl space are probably Monoflo (Bell & Gossett trademark) fittings. They do have a venturi inside but the idea of them being plugged with gunk is all but preposterous. Monoflo systems CAN be difficult to bleed all the air from but once bled they work very well. Are you certain there are no air vents on the radiators? Do you even have radiators or do you have finned tube baseboard convectors? If you have the baseboards you will likely need to remove the covers to access any air vents.

With a Monoflo system there is no set method of bleeding air. Sometimes it works better with the circulator running and sometimes with the circulator stopped. I would go through the entire system bleeding each vent with the system cold, then do it again while the system was warming up. Again, try it with the circulator running and try it with the circulator stopped for several minutes. You may need to bleed quite a bit of water before you get the air out. Make certain the make-up water Pressure Reducing Valve (PRV) is working properly to prevent the system pressure from dropping below about 10 psi while bleeding or you will NEVER get all the air out.
 
  #8  
Old 11-12-12, 07:10 AM
Member
Thread Starter
Join Date: Nov 2012
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Well, we got the temperature up inside. Another radiator downstairs just started working by itself. Some of the others seem to be putting out more heat.

There is just one circuit pipe, and what I grew up calling radiators all hook to that circuit. They are probably what you call finned tube convectors, certainly that is what they resemble. The bleeders are on radiators.

The copper pipes come off the iron pipe about 4-5 feet apart. The convectors have a bleed valve, A venturi system makes sense.

Haven't been able to get all the radiators working, but it almost seems like they are coming back more on their own, and each time the system shuts off, than with anything I am doing with bleeding and such. I turned the temp up, and close the water feed to the prv because I think it is leaking causing the pressures to get very close to relief.

Thanks for the info, and would appreciate any other suggestions anyone might have.
 
  #9  
Old 11-12-12, 09:18 AM
Member
Join Date: Nov 2012
Location: United States
Posts: 2
Received 0 Votes on 0 Posts
I also have a monoflo system, but I couldn't begin to match the expertise of the other seasoned vets here who have many thousands of posts to their credit---always follow THEIR ideas first, instead of mine.

First off, hats off to Furd for being able to pick up on the "taps" that had "supply/return" printing on them & identifying them as probably B&G monoflo venturis; and also identifying "radiators" as actually baseboard---both items flew right over my head into the wild blue yonder.

If the baseboard are coming back by themselves, maybe you should let it alone for a few days to see if they all come back without any intervention.

If it takes longer than that there are some additional things you can try---the 2 websites below recommend forced water purging, and the Taco site has a diagram as to one way this can be set up; the Comfort-Calc infers that you may have some piping connected to the non-working baseboards that have an air pocket because the piping inside the walls has settled & is no longer slanting upward, etc.; the Taco site recommends an Air Scoop at the near-boiler supply piping with a Hy-Vent attached to the top.

So each time you bleed the cold baseboards you get water, & assume that it's not an air problem--but in this case, it probably IS an air problem, according to the Comfort-Calc site.

1) My first attempt is done because it's least invasive------get a 3/8" fitting that will fit into the cold rad's bleed valve fitting (remove the bleed valve) & onto the hose fitting of a bicycle pump; several strokes of the pump, repeated over a 15-30 min. period is often enough to break up the air pocket that is illustrated in the Comfort-Calc illustrations---don't ask me why, but it usually works.

2) If the bike pump doesn't work, the next step is to do a force water purge, as illustrated in the Taco site below; as noted, any new water introduced has entrained air that will eventually come out of solution when heated, & will also have to be bled out of the system.

3) Check the system circ & determine if a stronger circ with more head would be more appropriate; having the pump positioned on the near-boiler supply line pumping away from the expansion tank is alway best.

http://www.comfort-calc.net/monoflo_system.html
http://www.comfort-calc.net/Monoflo_..._Bleeding.html
http://www.taco-hvac.com/uploads/Fil...limination.pdf
 

Last edited by Heizer; 11-12-12 at 09:47 AM.
  #10  
Old 11-12-12, 04:46 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
Heizer, are you suggesting to pump air INTO the system? I'm not going to ask you why! but yeah, that sure does sound counter productive doesn't it?
 
  #11  
Old 11-12-12, 06:57 PM
Member
Join Date: Nov 2012
Location: United States
Posts: 2
Received 0 Votes on 0 Posts
Smile

NJT:

It sounds absolutely ludicrous!

I first tried it many years ago when a forced purge didn't work & I was out of ideas.

I sent the idea to Siegenthaler & he told me to go to hell!

If you look at the drawings on the 2nd Comfort Calc site, you're looking at a very stubborn air pocket---no matter how often you open the bleed valve, all you get is water.

BTW: how's your new MPO.

You have no idea how much I've learned over the years from NJT, Grady, Furd, Xiphias, and numerous others; when I first stumbled on this site back then I couldn't believe some of the stuff being discussed; no other forum/site even comes close to the stuff being dealt with here, and it's only gotten better.


Thanks, everyone, the best of holidays to everyone, & God bless!
 
  #12  
Old 11-12-12, 09:44 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
I bet you aren't the first that Siggy has said that to!

MPO is doing just fine so far. Data collection is moot at this point since I was without power for 12 days after Sandy... but hasn't been too cold either.

Thanks for the best wishes! and same to you!
 
  #13  
Old 11-13-12, 07:42 AM
Member
Thread Starter
Join Date: Nov 2012
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Wow, those links help me understand both how the mono flow system works, and how to deal with it. Thanks alot!

Now, I suppose I will have a few other things to look at.
The slope of the pipes, time to get out the level, because the main circuit pipe all looks level.
The slope of the radiator feeds.

One thing I picked up on, when my father first moved in the house, there were three sets of feed lines for the second floor of the cape cod that were capped. The one article said you shouldn't really do that, but they were. Dad finished the upstairs bedrooms when I was very young. Years later, I helped him finish the bathroom, and the system fired up right away when we plumbed in the new convector to the capped lines.

I had one interesting thought, at work when we want to get air out of encapsulation liquid material, we vacuum the material, and the air bubbles get larger and move their way to the top. I was thinking, if I let the pressure off the system, and vacuum the high point with a standpipe or tank in between, the air pockets will expand and I might be able to get more of the trapped air out. I still think there is considerable air, and now I also understand how the air separator works.

I need to get one of those, haven't found it yet, found one I can order through lowes that looks different, and might have to use that.

Thanks again.
 
  #14  
Old 11-13-12, 01:00 PM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,493
Received 33 Votes on 25 Posts
I don't think that using a vacuum will help. As you wrote, using a vacuum will tend to make the bubbles larger and THAT is the problem. Increasing the pressure will have the opposite effect, make the bubbles smaller and when they are smaller they are less likely to completely interrupt the flow of the water. You need to get the bubbles to move.
 
  #15  
Old 11-13-12, 03:51 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
Yeah, forget the vacuum idea.

Two online suppliers that I've done biz with are

Patriot Supply - Industrial, Commercial & Residential HVAC Parts & Equipment

PEX - Radiant Heat - Radiant Heating - Plumbing Supplies - PexSupply.com

both are speedy delivery, have a vast array of 'stuff' available.

Pex Supply has a bit better search engine and better prices on some items, but you can't really call them and have the part time teenage high school girl help you find what you need.

Patriot Supply search engine is a bit tricky... you almost have to know what you want in order to find it, but if you call them you get a seasoned person who knows what they have in stock and what it is used for. Their pricing is usually a wee tad higher than PexSup...
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: