Two pipe steam radiator problems!

wilder0m

Jamie Hall said:

There should be no direct connection between the steam main and the dry return. Either a water seal and crossover trap, or no connection at all.

I may have been unclear. The steam main connects to the return at ground level, so I believe that would be at the "wet return." However, it's getting hot there, and before some of the supply branches off the main are even hot.

mattmia2 said:

Does it drop down before the main connects to the return? This could be a case where either the pressure is too high and pushing the water out of a water seal or the water line of the current boiler is lower than that of the original boiler. It could also just plan be reworked incorrectly since it looks like someone has done a lot of work to modify that system.

Yes it does drop down first. The elevation at the connection point should be well below the current water line. Nevertheless it's getting hot there!

Jamie Hall

wilder0m said:

Steamhead said:

wilder0m said:

So, the supply main connects to the return main right after the return drops to ground level (after all individual radiator returns feed into it, and after the dry return vent). That is where it gets hot. The entire supply main is hot (as expected) but then the return also gets hot for several feet after the supply connects to it. Are they supposed to be connected there? It seems like steam is being directly fed into the return there. 

After that, the return (what I assumed was the wet portion because it’s at ground level) crosses the basement, then turns vertical upwards again for a few feet right next to the boiler, then connects back to the boiler. I can share more pictures tomorrow. 

The steam main and the dry return should both drop below the boiler's waterline before connecting together. This way, water will stand in the drips (vertical pipes) and steam will not be able to get from one to the other.

This is the case. They drop down before connecting. But somehow, right the area of the wet return right after the connection from the main supply is getting hot. Does that mean there isn’t water there and there should be? 

most likely -- and the reason may be, as @mattmia2 said, that the pressure gets too high. Not too high all the time, but just before the boiler shuts off. You can check this. For every pound of pressure at cutoff, the drop from the dry return down to the bottom of the loop must be at least 28 inches -- and half again as much is better. Worse, depending on how the main is ptiched, it may take several days from a single overpressure event for the seal to build back up.

wilder0m

Jamie Hall said:

most likely -- and the reason may be, as @mattmia2 said, that the pressure gets too high. Not too high all the time, but just before the boiler shuts off. You can check this. For every pound of pressure at cutoff, the drop from the dry return down to the bottom of the loop must be at least 28 inches -- and half again as much is better. Worse, depending on how the main is ptiched, it may take several days from a single overpressure event for the seal to build back up.

I really want to understand this better. I believe I have the required drop, it goes all the way from near the ceiling to the floor in the basement. And the wet return is well below the boiler water level. Where in the system would be the "seal" we are talking about?

mattmia2

The water is the seal. The low spot will fill with condensate and that water will stop air and steam from traveling through that section of pipe but water can still pass.

If the differential between the main and the return is higher than the weight of the column of water in that pipe, the steam from the main will push that water out of the low spot.

What type of gauge are you reading pressure on? Is it a 0-3 psi or 0-5 psi gauge or a gauge calibrated in oz/in^2? A 0-30 psi gauge does not read accurately in the low pressures that a low pressure steam system should be running but it is required by code.

wilder0m

mattmia2 said:

The water is the seal. The low spot will fill with condensate and that water will stop air and steam from traveling through that section of pipe but water can still pass.

If the differential between the main and the return is higher than the weight of the column of water in that pipe, the steam from the main will push that water out of the low spot.

What type of gauge are you reading pressure on? Is it a 0-3 psi or 0-5 psi gauge or a gauge calibrated in oz/in^2? A 0-30 psi gauge does not read accurately in the low pressures that a low pressure steam system should be running but it is required by code.

Thanks! That makes it a lot clearer for me. Yes it's a 0-30 psi gauge so I don't know the pressure accurately. But I have now reduced the pressuretrol down to 1.5 main/0.5 differential per @Jamie Hall's recommendation. And, now I have a picture to illustrate things more clearly:

Jamie Hall

Oh now that's interesting... well, it could still be excess pressure, but only if that wet return isn't equalized at the boiler.

wilder0m

@Jamie Hall now I’m on the edge of my seat. What’s interesting about it?

I started to wonder if those pipes are just getting hot because they are copper and conducting the heat from the hot supply main touching them?

reggi

Jamie Hall said:

Oh now that's interesting... well, it could still be excess pressure, but only if that wet return isn't equalized at the boiler.

But wouldn't the path of least resistance be up the return ( Under the right circumstances) but I don't what else is going on behind that sheet of plywood..a little close to that Panelbox

wilder0m

reggi said:

But wouldn't the path of least resistance be up the return ( Under the right circumstances) but I don't what else is going on behind that sheet of plywood..a little close to that Panelbox

Behind the plywood there is just the vent on the dry return (a Hoffman which some have suggested here to replace with a Gorton #2 for more venting).

Is it possible that the copper return piping at ground level is just getting hot due to conductivity and contact with the supply pipe right above it (as opposed to steam getting into it)?

reggi

wilder0m said:

But wouldn't the path of least resistance be up the return ( Under the right circumstances) but I don't what else is going on behind that sheet of plywood..a little close to that Panelbox

Behind the plywood there is just the vent on the dry return (a Hoffman which some have suggested here to replace with a Gorton #2 for more venting). Is it possible that the copper return piping at ground level is just getting hot due to conductivity and contact with the supply pipe right above it (as opposed to steam getting into it)?

Now if it me and I didn't have the answer I'd let the system cool down a bit , then I'd get my Ir machine and start up the system, grab a chair and wait for that steam to come and follow it to where it goes, now you have to monitor each one from I'd say 10 ft away from where they meet so you're able to follow it to see where it goes and slowly heats the pipes or quickly heats it and which one(s) and how far...
From there your answer will be simple for someone to figure out..as long as you have the information as described..

ethicalpaul

Jamie Hall said:

Oh now that's interesting... well, it could still be excess pressure, but only if that wet return isn't equalized at the boiler.

That's not "a thing"

Jamie Hall

Thing or not, the point of my comment is that if that wet return is equalized at one end to boiler steam pressure, and it is full of water, the water level at the two drips in the picture cannot be less than the water level in the boiler and may, if there is a pressure drop in the steam main and the dry return is vented, be greater. Therefore it would not be possible for steam to push down from the steam main into the wet return.

wilder0m

reggi said:

wilder0m said:

But wouldn't the path of least resistance be up the return ( Under the right circumstances) but I don't what else is going on behind that sheet of plywood..a little close to that Panelbox

Behind the plywood there is just the vent on the dry return (a Hoffman which some have suggested here to replace with a Gorton #2 for more venting). Is it possible that the copper return piping at ground level is just getting hot due to conductivity and contact with the supply pipe right above it (as opposed to steam getting into it)?

Now if it me and I didn't have the answer I'd let the system cool down a bit , then I'd get my Ir machine and start up the system, grab a chair and wait for that steam to come and follow it to where it goes, now you have to monitor each one from I'd say 10 ft away from where they meet so you're able to follow it to see where it goes and slowly heats the pipes or quickly heats it and which one(s) and how far...
From there your answer will be simple for someone to figure out..as long as you have the information as described..

I have done that (not with an IR but by touching). The supply pipe is getting hot and then when the heat reaches the drop section it spreads the the return pipe at the floor. The drop section of the return pipe, directly under the vent, is NOT hot at all. 

reggi

wilder0m said:

reggi said:

wilder0m said:

But wouldn't the path of least resistance be up the return ( Under the right circumstances) but I don't what else is going on behind that sheet of plywood..a little close to that Panelbox

Behind the plywood there is just the vent on the dry return (a Hoffman which some have suggested here to replace with a Gorton #2 for more venting). Is it possible that the copper return piping at ground level is just getting hot due to conductivity and contact with the supply pipe right above it (as opposed to steam getting into it)?

Now if it me and I didn't have the answer I'd let the system cool down a bit , then I'd get my Ir machine and start up the system, grab a chair and wait for that steam to come and follow it to where it goes, now you have to monitor each one from I'd say 10 ft away from where they meet so you're able to follow it to see where it goes and slowly heats the pipes or quickly heats it and which one(s) and how far...
From there your answer will be simple for someone to figure out..as long as you have the information as described..

I have done that (not with an IR but by touching). The supply pipe is getting hot and then when the heat reaches the drop section it spreads the the return pipe at the floor. The drop section of the return pipe, directly under the vent, is NOT hot at all. 

So the supply drop gets hot, at the floor the return drop gets hot ( How far up ? If it's exerting pressure it's height should be no higher than the boiler waterline ,,)
and what of the wet return at this time?  Does it get hot before the return backfills ? 
And we're assuming the wet return is getting hot from the return.. it's not coming from any other connection downline ... Right?

wilder0m

reggi said:

So the supply drop gets hot, at the floor the return drop gets hot ( How far up ? If it's exerting pressure it's height should be no higher than the boiler waterline ,,)
and what of the wet return at this time?  Does it get hot before the return backfills ? 
And we're assuming the wet return is getting hot from the return.. it's not coming from any other connection downline ... Right?

Let me clarify. The heat spreads in this order: 1. Supply main (overhead) 2. Supply drop 3. Wet return (ground level). All of those are connected as shown in the picture above. The dry return main and the drop from the dry return to the wet return are NOT hot. I.e., in the picture, the vertical drop on the left is hot, but the one on the right (partially hidden by plywood) is not. This tells me that the heat in the wet return is coming directly from the supply, not coming back from the radiators.

Steamhead

wilder0m said:

reggi said:

So the supply drop gets hot, at the floor the return drop gets hot ( How far up ? If it's exerting pressure it's height should be no higher than the boiler waterline ,,)
and what of the wet return at this time?  Does it get hot before the return backfills ? 
And we're assuming the wet return is getting hot from the return.. it's not coming from any other connection downline ... Right?

Let me clarify. The heat spreads in this order: 1. Supply main (overhead) 2. Supply drop 3. Wet return (ground level). All of those are connected as shown in the picture above. The dry return main and the drop from the dry return to the wet return are NOT hot. I.e., in the picture, the vertical drop on the left is hot, but the one on the right (partially hidden by plywood) is not. This tells me that the heat in the wet return is coming directly from the supply, not coming back from the radiators.

I bet it's just hot condensate from the steam main, dropping into the wet return.

reggi

Steamhead said:

So the supply drop gets hot, at the floor the return drop gets hot ( How far up ? If it's exerting pressure it's height should be no higher than the boiler waterline ,,)
and what of the wet return at this time?  Does it get hot before the return backfills ? 
And we're assuming the wet return is getting hot from the return.. it's not coming from any other connection downline ... Right?

Let me clarify. The heat spreads in this order: 1. Supply main (overhead) 2. Supply drop 3. Wet return (ground level). All of those are connected as shown in the picture above. The dry return main and the drop from the dry return to the wet return are NOT hot. I.e., in the picture, the vertical drop on the left is hot, but the one on the right (partially hidden by plywood) is not. This tells me that the heat in the wet return is coming directly from the supply, not coming back from the radiators.

I bet it's just hot condensate from the steam main, dropping into the wet return.

I concur 

Jamie Hall

Steamhead said:

wilder0m said:

reggi said:

So the supply drop gets hot, at the floor the return drop gets hot ( How far up ? If it's exerting pressure it's height should be no higher than the boiler waterline ,,)
and what of the wet return at this time?  Does it get hot before the return backfills ? 
And we're assuming the wet return is getting hot from the return.. it's not coming from any other connection downline ... Right?

Let me clarify. The heat spreads in this order: 1. Supply main (overhead) 2. Supply drop 3. Wet return (ground level). All of those are connected as shown in the picture above. The dry return main and the drop from the dry return to the wet return are NOT hot. I.e., in the picture, the vertical drop on the left is hot, but the one on the right (partially hidden by plywood) is not. This tells me that the heat in the wet return is coming directly from the supply, not coming back from the radiators.

I bet it's just hot condensate from the steam main, dropping into the wet return.

I concur also...

wilder0m

@reggi @Steamhead @Jamie Hall Glad there is consensus! Is that okay that this is happening or a sign of a problem?

On another note, I think I have identified the funny antique valves on the two radiators that aren't working. I will post what I found later.

Sylvain

You might be interested by this thread:
https://forum.heatinghelp.com/discussion/194622/anyone-try-using-orifices-instead-of-steam-traps?
and this one:
https://forum.heatinghelp.com/discussion/168913/orifice-plates-install?

I don't see the equalizer on your boiler's pictures

wilder0m

Sylvain said:

You might be interested by this thread:
https://forum.heatinghelp.com/discussion/194622/anyone-try-using-orifices-instead-of-steam-traps?
and this one:
https://forum.heatinghelp.com/discussion/168913/orifice-plates-install?

I don't see the equalizer on your boiler's pictures

Thank you for those threads, I will look through. Just so I understand, is your comment re: the equalizer related to those linked threads, or just a separate observation?

I'm still new to this but from what I understand the equalizer would be the pipe running up from the wet return back to the header? Labeled in this picture. Is that correct?

Jamie Hall

that's it

ethicalpaul

And it doesn't do anything related to your system's pressure or steam flow, just to remove one variable.

Sylvain

wilder0m said:

Just so I understand, is your comment re: the equalizer related to those linked threads, or just a separate observation?

it is separate.
The equalizer was not visible in previous pictures.

wilder0m

Sylvain said:

wilder0m said:

Just so I understand, is your comment re: the equalizer related to those linked threads, or just a separate observation?

it is separate.
The equalizer was not visible in previous pictures.

You're right, thank you.

reggi

@wilder0m ... Next question... How do you monitor your water level ? 

wilder0m

reggi said:

@wilder0m ... Next question... How do you monitor your water level ? 

Great question! I just took out the sight glass to clean it the other day, managed to get it clean and back installed, opened the valves and saw that the water level was fine, then stupidly tried tightening the nuts a bit further and broke the glass. So now I’ve ordered new parts to replace it. Wish me luck!

wilder0m

Jamie Hall said:

On the valves. You can use regular radiator valves on a vapour system, but it isn't recommended. The existing valves may be repairable (in fact, they almost always are). If you want to use regular valves, though, be prepared for some work: you will have to remove the spud from the radiator to match up with the new valve. That's no fun. Then you will need to start with the new valve almost closed, and experiment with opening it a little at a time until the radiator, after a nice long run, gets hot about three quarters of the way across, but the return pipe does not get hot. This will take patience. Then mark the valve so when someone with busy fingers messes with the setting you can restore it. You could also use an orifice -- but that takes a steam guy to size and fit, and you don't seem to have one.

So I'm going to try the route of replacing the valves on my 2 problem rads with ordinary radiator valves, even though it may not be optimal, because:

1. I can't find a local contractor that seems expert enough to trust with either repairing the old valves or installing orifice plates.
2. All of my radiators with ordinary valves (9 out of 11) are at least heating, with their valves fully open (although from your quoted comment above I understand that this may not be their optimal state).

I will have a local plumber do it, but I want to make sure I understand the work myself. Is this the kind of valve they would put on (assuming the pipe size is correct)? https://www.supplyhouse.com/Bluefin-RVST075-3-4-FIP-x-Male-Union-Steam-Angle-Radiator-Valve

Do I need any other parts? Is the spud that has to be removed from the radiator a part that needs to be replaced separately, or is it a part of the new valve?

Thanks.

guzzinerd

The threaded part in the supply house pic is the new spud (i.e. is included).  You can see the large nut attaching it to the valve. 

reggi

wilder0m said:

@reggi @Steamhead @Jamie Hall Glad there is consensus! Is that okay that this is happening or a sign of a problem? On another note, I think I have identified the funny antique valves on the two radiators that aren't working. I will post what I found later.

@wilder0m ... If you still need a hand identifying those valves you can photograph the side that appears to have raised letters that appear to spell out something, maybe even their name..

wilder0m

Thanks @reggi -- I believe I have already identified them. I will share in a separate post since what I found is interesting (to me at least), but will probably wait until I have them off the radiators so I can photograph the inner workings.

reggi

@wilder0m .. I'm intrigued... Interesting is good unless it has something to do with them not functioning on the radiators they're attached to.. such as being corroded and/or blocked.. though I don't believe you mentioned if the prior owner had issues with them? 
NOW with that 1 radiator being 25 sections+/-  where is it ( and the other one) in relation to the end of the Main that goes into the wet return that is "Steaming Hot"  as your pressurestrol was ? set pretty high originally and with those 2 radiators being "offline ' your boiler was at least a additional 30% +/- oversized ( as compared to whatever it was originally, most likely oversized) which would ( without shutting down) keep on pushing steam into whatever space"gives" which most likely include your return.... ,
So Yes .. getting those valves swapped out or opened should help settle your system out... 
Just my opinion..

wilder0m

@reggi thanks, I hope you're right. The supply branch going to the problem rad is the 6th out of 7 branches on the way from boiler to return. And the drop from supply main to return is getting hot before that branch even starts to get warm. So I do think the "path of least resistance" for the steam is to skip right by that branch. That said, it does get hot eventually, but the radiator still doesn't. Crossing my fingers that replacing the valve improves it.

delcrossv

For those valves, I think you need these.

https://www.mepcollc.com/product/swrf-c-regulator/

Steamhead

delcrossv said:

For those valves, I think you need these.

https://www.mepcollc.com/product/swrf-c-regulator/

This.

@wilder0m , we can't wait to see your original valves!

wilder0m

@delcrossv @Steamhead -- what is special about those MEPCO valves, and where can I buy them? I already bought a pair of these and was about to put them on this week: https://www.supplyhouse.com/Bluefin-RVST075-3-4-FIP-x-Male-Union-Steam-Angle-Radiator-Valve

What would be a sign they are not working well enough and need to switch to the MEPCO valves?

Steamhead

The MEPCO valves have adjustable orifices built in. Using these, you can adjust the amount of steam that can enter the radiator at a certain pressure, so the steam won't reach the return lines. If you use the Bluefins, you'll need to add orifice discs in the valve unions, which you would have to drill out to the proper size. The MEPCO valves make the process much easier.

wilder0m

Steamhead said:

The MEPCO valves have adjustable orifices built in. Using these, you can adjust the amount of steam that can enter the radiator at a certain pressure, so the steam won't reach the return lines. If you use the Bluefins, you'll need to add orifice discs in the valve unions, which you would have to drill out to the proper size. The MEPCO valves make the process much easier.

Thank you. What I'm struggling to understand is how all the other radiators are working fine, as I don't think they have any special valves or orifices on them.

I also doubt that the guy I have coming to install the valves would have the knowhow to configure/adjust the orifice plates properly (nor have I been able to find anyone else locally who might).

Would you say the MEPCO valves are a *necessity*, or could I get passable results with the Bluefins at least as an interim solution? There's significant time sensitivity here, as we are without heat in the bedroom every day this goes on.

Jamie Hall

You can get heat with the Bluefins. Mepcos, while much easier to adjust -- and the adjustment doesn't drift -- are what should be there, but...

Now. Having said that, how to adjust? Start off with the Bluefin almost completely shut off. Find out how much of the radiator heats on a typical heating cycle. If not enough of it does to keep the space at the temperature you like, open the valve just a bit -- maybe a quarter turn. Check again. Keep doing this until about three quarters of the length of the radiator, or maybe a bit more, heats or you are happy with the heat in the space and then stop. That's as open as you want it to be, as any more may let steam into the return -- which won't stop that radiator, but may stop others on the same return. When you find the sweet spot, mark the valve in some way so that when someone with itchy fingers plays with it you can restore it to where it needs to be...

reggi

@wilder0m ... I guess those non-working valves aren't anything special if Bluefins work in their place... Glad you have your system sorted out..