Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit

One Cold Radiator (part 2)

KbalzKbalz Member Posts: 53
Hello, this is a continuation of my first thread, which got very busy with replies.

<a href=""></a>

Summary of old thread:

- Even though the title is One Cold Radiator, I actually had two radiators which were hot and cold in streaks (as in hot for a week, then off for a week).. while the rest of my five radiators are always hot.

- After some investigation, we found that I was under vented.

- Discovered a slow leak on my LWCO blow off valve

Since my last post in the previous thread, my army of new vents arrived. Seven Hoffman 1As and Two Gorton No. 2's. All have been installed. (Gortons pictured below).

For two nights, all radiators were perfectly hot, just as I expected. BR2 has been hot for a full week now! However, on the third night, the BR1 room (my sons room) was again Cold :-( Before running back here, I performed a few experiments.

1. I removed the air vent from the cold radiator, and about 1/4 or 1/2 oz of water spilled out of it. At first, I thought that was causing the vent to block, so I shook all of the water out. After about 2 minutes, the steam arrived at the radiator, and I put the same vent back on. 24 hours later, it was cold again.

2. I switched the air vent with BR2, thinking maybe I had a defective vent (again when I removed it, water poured out). After about 2 minutes of being without a vent, the steam arrived at BR1. After switching the vents, both remained hot for 24 hours, but then again, the BR1 went cold while BR2 stayed hot (so the problem did not follow the vent, remained at the radiator).

3. I shut off two radiator's feed pipes BR2 & FR2 (the small one) thinking that would somehow convince the steam to move to BR1 - that experiment also failed.

So replacing the vents had positive impact on BR2, but BR1 still has a problem. I've attached many pictures of the bad radiator. The radiator itself is pitched a little bit, I attached a picture with a level on it.

I checked the pitch of the main steam pipe, and it is pitched equally throughout the basement, about a half a bubble is over the line.

What else can I check?


  • BobCBobC Member Posts: 5,118

    The fact it works fine for a while and then goes stone cold makes me think you might have a horizontal steam pipe that is just a bit off pitch. Perhaps a short one that connects to the radiator valve from inside a wall.

    Make very sure all the piping that supplies theis radiator has the proper pitch - with a level. then try levering up that radiator and see if you can put a 3/4" piece of plywood underneath the air vent end and a 1/2' under the valve end.

    that should tell us if you have a pitch problem in that short connector pipe.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • RodRod Posts: 2,067
    More Slope?

    Hi- I agree with Bob. First thing I would do is increase the slope of the radiator a bit (add quarters ($0.25) under the feet at the end away from the intake pipe and see whether that makes a difference. If not difference, add another pair of quarters etc.etc.  This will accomplish two things:

    1. It will help the condensate drain from the radiator 

    2. It will put a little outward pitch on the fitting going into the vent (and the vent) which should help water drain from the vent. It is possible to have too much slope so that all the condensate (water) rushes to one end and blocks the incoming steam so don't over do it! :)

    After experimenting with the above I would then, as Bob suggested, try elevating the whole radiator a bit. Usually there is a little slack in the steam pipe and even a bit more elevation, increases the slope of the pipe to the main. Do it very slowly and carefully! A short length of 2x4 as a lever and some blocks for a fulcrum works well and takes the strain off your back. Have someone steady the radiator as you are lifting it. After raising the whole radiator, again add shims to put proper slope so the condensate drains off.

    How is the quality of your steam? Does the water line bounce much? Is the inside of the sight glass have condensation above the waterline?

    Didn't you have problems with your LWCO leaking (?) Have you got that fixed? If not let me know the model number I have a parts list for several of the LWCO models.

    - Rod
  • KbalzKbalz Member Posts: 53
    edited December 2010

    Bob and Rod, thanks for the responses! Several weeks ago I added three quarters to each vent-side leg, this got me the pitch amount that is pictured. If I add more or too many quarters, is there any chance of over straining the feed pipes or union between the shut off valve and radiator?

    Same question posed for when the entire radiator is raised off the ground using a fulcrum & lever?

    Will check LWCO (not fixed) model number, steam bounciness, and sight glass quality tonight.
  • RodRod Posts: 2,067

    Too much strain?- without being there, that is a hard question to answer and you are quite right to be concerned. It will depend a lot on how much free movement there is in the piping and how much slack there is in the hole where the pipe comes through the floor.

    A quarter ($0.25) is .069 0f an inch thick. Two of them are .138 just a little over 1/8 of an inch and 3 of them (.207) is just under a 1/4 of an inch. I think you could add at least 2 more with no problems. One of the reasons I like using a fulcrum and a lever is you can judge how much strain is coming on to the pipe.

    - Rod
  • KbalzKbalz Member Posts: 53

    LWCO Brand - McDonnell No.0067

    Water Bounciness - it seemed to slowly rise and fall, 1/4 inch oscillations. Sometimes it is rather still. I can video this if that would help.

    Sight glass condensation - none above the water line.

    I don't know how well the water was maintained by the previous owner, lets assume not at all. Does my boiler have a way to skim?

    Did not have time for adjusting the radiator pitch yet, should have more time this evening.
  • RodRod Posts: 2,067
    Dry Steam!


    Sight glass water - No bounciness, No Condensation in Sight Glass = Dry Steam ! Congratulations!

    I've attached the 67 LWCO Installation manual and the 67 parts manual.

    You might want to consider replacing the whole thing if it's beat up. I think the recommendation was renewal after 10 years of operation. Keep in mind that  this is a safety device so you don't have the option of waiting until it breaks to fix it. If it breaks down and can't do its job, you are in Big Danger!

    - Rod
  • KbalzKbalz Member Posts: 53

    Thanks, there is some paper work at the house with LWCO installation dates, I'll have to check, but I'm certain it is at least 15 years old.

    My particular LWCO has a different shut off handle than what is pictured, mine is a circular turn handle like an older outside garden hose.. while the one pictured is a modern handle bar (sorry for my terminology!).

    Would I replace my LWCO with the same model, or is it okay to install a newer version on my older boiler (if there even is a newer lwco model) ? Also, is there a website you recommend to purchase one, or direct from mfg ?
  • RodRod Posts: 2,067

    Try Pex Supply on the internet. Type mcdonnell 67 in the search window.

    - Rod
  • World PlumberWorld Plumber Member Posts: 389
    riser location

    Is your riser to this radiator close to the return? How much distance is there from that to the water level in the boiler?  Should be a minimum of 30 inches.

        I had a similar problem when I moved in when I filled the boiler to the factor mark on the jacket I could not get heat in the front rooms. After much head banging and emptying the boiler out on the second floor.  I figured out that the boiler pressure was pushing the water up and blocking the riser. So I had to run the boiler at a lower level until I dug the basement floor down.
  • KbalzKbalz Member Posts: 53

    Hello, no actually this particular radiator's riser is either first or second on the main steam pipe.

    If you check my older thread which I referenced in my first post, there is a top-down sketch of my system. BR1 is the radiator that is hot for some time, then cold until I remove the air vent. BR2 and FR2 are near the end of the main steam.

    There is also some near-boiler pipe pictures in my old thread that may answer more questions. Sorry I did not reply in that thread, but it was getting too messy for me :)
  • KbalzKbalz Member Posts: 53
    Pitch increased

    Just an update: I increased the pitch of the radiator last night. I threw my level on it, and it is pitched much further than before (bubble now touching the edge of its limit).

    I went from 3 US Pennies to 5 US Quarters under each vent-side leg. I have not raised the feed-side legs.

    I'll update this thread again in a few days if all is well or not.
  • KbalzKbalz Member Posts: 53

    Jan 3rd - Jan6th, the radiator was running great using the 5 quarters to create pitch. At some points on the 7th, it went cold. I called a friend over and we raised the entire radiator.

    Feed-side legs were raised onto a 1/2" ply wood, and the vend-side legs were raised onto a 3/4" ply. I honestly don't think I can raise the feed side legs any further, even with full weight on the lever we were using, it would only budge a little more.

    The radiator was hot again from Jan 8th until mid-day on the 11th.

    I added two more quarters to the vent side legs.. my level showed lots of pitch (the bubble was touching the edge of its limit).

    The radiator was again hot for a few hours, then out cold.

    Note that each time, after I would change the pitch, I would HAVE to remove the rad vent in order to get it hot again. Literally 3 minutes with that vent off, and I have steam coming out of the vent hole every time. I am considering installing a Gorton No 2 on the radiator somehow. Unless there is something more sensible I should try?

    The Hoffman 1A says there is a max PSI of 10, could that be the hidden probelm? The rest of the radiators vents are working great, and I've swapped them around six times already. Should I pitch the radiator in a second direction: meaning toward the feed pipe and to the left of it?
  • nicholas bonham-carternicholas bonham-carter Member Posts: 8,161
    one problem solved one to go!

    now you have the radiator draining properly. also now you know that in order for the radiator to get steam, you have to take the vent off, in order for enough air to be removed.

    check the main vent for this line below, and see why it isn't doing its job. if you simply vent that line through that radiator, you run the risk of bringing back the excess water problem.--nbc
  • KbalzKbalz Member Posts: 53

    Okay, how do I check if the main steam vent is doing its job? After I installed the vents, for a few days I would reach up and ensure they were at least hot, and they were every time I checked. There is no evidence of leak at the main vent. How do I check it further?
  • KbalzKbalz Member Posts: 53
    Is this normal?

    Once the rad goes cold, the only way to get heat is to remove the vent. Every time I remove the vent, I can shake about half ounce of water out of it.
  • KbalzKbalz Member Posts: 53

    I'm considering disconnecting the radiator, maybe there is some kind of blockage. Any tips on that process?
  • nicholas bonham-carternicholas bonham-carter Member Posts: 8,161
    watery vent

    i think too much water is being carried up to that radiator by the air trying to escape the radiator vent. i would increase your main venting, and decrease the radiator venting. do you know what your exact pressure is in ounces during the venting phase?--nbc
  • KbalzKbalz Member Posts: 53
    Main Venting

    Pressure - I've never seen my 0-30 psi move, and I've read on these forums that is typical. I do not have any other pressure gauge so to answer your question: sadly no.

    Main Venting - Mid December I upgraded from a Hoffman 4A (I think) to two Gorton No. 2s.. This is for one main steam line, 70 feet long, 2 inch inner diameter. You mentioned earlier that the main vents may not be doing their job, how can I confirm that exactly?

    Rad Venting - I'll try lower this weekend. It has a Hoffman 1A adjustable, I've been trying on 6, 5, 4, and 3.. We (well BobC and Rod) calculated all EDRs in my first thread which is linked above in the first post, this rad was around 30.3 EDR.
  • KbalzKbalz Member Posts: 53
    edited January 2011

    In my boiler manual, it states the NWL is to be 22inches from the ground. What exactly is NWL? My guess is Normal Water Level (?)
  • KbalzKbalz Member Posts: 53
    edited January 2011

    Saturday I raised the radiator a tad further.. the front legs are now 5/8" board, and the back legs are now on a 5/8" board PLUS three quarters under each leg. Saturday the radiator still was cold however.

    When I first had my cold radiator problem, I read every word in the boiler manual. It said the NWL was 22 inches from the ground.. so I marked on the glass where that was, and that is where I would fill it to every week.

    Sunday I overfilleded it to around 25 inches, and didn't have time to drain out the 3 inches, so I just fired it up. The cold radiator warmed up just like the others in the house. To date, this radiator has not been able to get to a warm state without me removing the vent.. but this time was different, it got hot all on its own!

    The radiator has stayed hot all week, but it has to go longer before I will celebrate. Actually the whole house is too hot now, I had to reprogram the thermostat to be 2 degrees cooler.
  • Mark NMark N Member Posts: 1,087
    Dumb Question

    Does your boiler sit on the floor or on blocks? If it is blocks or a pad measure from this not the floor. Is 22" in the middle of the glass or is 25"?
  • KbalzKbalz Member Posts: 53

    It has some kind of feet, but they are less than an inch off the ground - the room's floor slopes slightly toward a drain, so the feet are probably there to level the boiler.

    25" is near center of the sight glass
  • Mark NMark N Member Posts: 1,087

    When the boiler is off and the water has cooled the NWL should sit at the middle of the glass or maybe slightly above that.
This discussion has been closed.


It looks like you're new here. If you want to get involved, click one of these buttons!