Respect the old boiler's water line in a replacement?

Jack M

This old boiler is raised up on cinder blocks (hence the high water line). Its been said that you should match the old water line when replacing the boiler (existing water line is marked on the wall). The (existing) system does not have any known issues with hammer or water use (just replace water from LWCO blowdown). With this new install I'd like to drop the water line.
The existing waterline is 4 ft off the floor and 2 ft below the header (no drop header). With the replacement I'd like to move the water line lower to 2 1/2 ft off the floor and 3 1/2 ft below the header (adding a drop header and a Hartford). That would put the boiler up on a 6" cement base (in case there's ever water in the basement).
To what extent does the existing water line need to be respected/maintained?

BobC

Make sure any and all wet returns will be well below whatever waterline you end up with. If there is more than one return make sure they tie together well below the waterline.

Bob

Abracadabra

You can also utilize a false water line.

Jack M

Abracadabra said:

You can also utilize a false water line.

What is a "false" water line? I have heard of replacement boiler systems that ended up with problems (including banging piles, radiators that did not get steam, low water cut offs during cycling) because they new installation changed the water line.
Are these problems a result of establishing a water line "higher" than the old or can a "lower" water line cause the similiar problems?

ChrisJ

Wow,
Whoever did that could've at least rotated the second course of blocks 90 degrees to make it more stable.

If in doubt, post some pictures of the rest of the piping. Will any horizontal runs that are now wet become dry when you drop the water line?

Abracadabra

http://www.comfort-calc.net/Steam_False_Water_Line.cfm

Jamie Hall

Yes, you can use a false water line. They usually work. Pretty well. After a fashion. Sometimes.

They are, in my not very humble opinion, a last resort bandaid solution to a botched install.

There has to be a very very good reason indeed to not respect the old water line (plus or minus an inch or two). Bluntly, I don't see one in your situation.

What is your reasoning? I'll listen to anything...

Jamie Hall

Actually, I probably shouldn't be so mean. I can think of situations involving odd basement layouts etc. where a false water line for part of a system might be needed...

nicholas bonham-carter

It all boils down to keeping the wet returns wet. An old, tall boiler may have had a waterline height which enabled the wet returns to stay wet, even though the pipe was high off the floor.
When the new boiler is installed, the waterline, is now closer to the floor, may be below the height of the return piping. This now breaks the water seal which is needed in the returns, and enables steam to get into pipes which should never see steam.
All you have to do is to make sure the new waterline height exceeds the height of the piping, or lower the piping. You can never have returns which are too low.--NBC

Underdog

The existing return is about 12" off the basement floor. So by lowering the return to some degree , I'm assuming the water line (with the replacement boiler) can be lowered as well without impacting the system? I'd like to get a drop header above the boiler. The existing boiler looks strange perched up on two cement blocks. I'd rather see the boiler 6" off the floor at most. I cannot understand why it was placed up so high to start with. Then again I may be missing something. I'll take a photo.

Jamie Hall

Couple of thoughts.

First, on the wet returns. What you will need to do if you really want to lower them and the boiler is to go out in the system and find every single last connection from above. All the drips, from dry returns, steam mains, radiators, etc. everywhere in the system, and make sure that the connection with the horizontal part of the wet return is at least six inches below the boiler water line. Every single last one of them. It's those connections that are critical, and some of them out at the ends may be quite close to the water line as it is, never mind where it will be. You will need to extend those verticals down.

A drop header can be installed perfectly well with the higher location. It is the vertical dimension up to the first elbow over which is important, and should be 24 inches -- more than that is OK, but shouldn't be necessary. The drop header itself can be at any elevation that's handy, so long as it is above the maximum water line of the boiler. That is not a factor.

I can understand the aesthetics of not wanting the boiler up on a pedestal. But... do not sacrifice operation for aesthetics.

SWEI

Given the heights of currently boilers, I'd probably design a steel platform with some open space underneath. OTOH, that might encourage someone to store paint thinner underneath...

MegaSteam might be a good option in any case.

BobC

Good place for the cat to nap.

Bob

ChrisJ

Underdog said:

The existing return is about 12" off the basement floor. So by lowering the return to some degree , I'm assuming the water line (with the replacement boiler) can be lowered as well without impacting the system? I'd like to get a drop header above the boiler. The existing boiler looks strange perched up on two cement blocks. I'd rather see the boiler 6" off the floor at most. I cannot understand why it was placed up so high to start with. Then again I may be missing something. I'll take a photo.

If you can share pictures of everything I think it'll put everyone's mind at easy.

You need to make sure no horizontal runs will end up partially filled with water at any point otherwise they could and probably will hammer. You also need to make sure you have all returns isolated from each other by water.

Personally, I'd see what I needed to do to lower the boiler rather than just guess and put it up on blocks.

Jack M

Here are some images of the "above boiler" piping.

nicholas bonham-carter

It's hard to see what is connected to what in those pictures. Is there an equalizer?--NBC

Jack M

nicholas bonham-carter said:

It's hard to see what is connected to what in those pictures. Is there an equalizer?--NBC

Yes, hard to see. Maybe a video would be helpful. I'll give that a try.

ChrisJ

Jack M said:

nicholas bonham-carter said:

It's hard to see what is connected to what in those pictures. Is there an equalizer?--NBC

Yes, hard to see. Maybe a video would be helpful. I'll give that a try.

Is there only that one steam main and one return?
If that's the case it looks like an easy change.

Jack M

Yes, one steam main and one return. The thought was to keep it simple and install an above boiler piping kit. However that might change the water line. The equivalent of sacrilege in dead man protocol.

Fred

No Piping kit, above the boiler is going to change the water line. It's the water line in the boiler, when the boiler is idle that you are concerned about. If you onlky have the one main, and the one return, it would appear to be fairly easy to extend that vertical return down to the floor, carry that horizontal wet return (currently right under the chimney clean-out) across the floor, when you get to the new boiler, follow the specs from the boiler manufacturer as it relates to your Hartford loop and where to tie it into the equalizer.

Jack M

I can't find the existing equalizer. The equalizer is supposed to balance the pressure between the header (supply side of the boiler) and and the return side of the boiler. Can anyone point it out?
The recommended piping is attached. Main is not to be less than 28" above the water line. The "T" of the Hartford connection has to be 2" below the water line (cold). The base of the highest pipe on the (drop) header is 24" above the WL.

Fred

We can't see the other side of the boiler to know if an equalizer is there or not. I will tell you, when you install a new boiler you will likely end up with two Mains rather than the one you have now. That angled riser off of you boiler ties into a Bull Headed Tee with the Main going in opposite directions. You need to take that Tee out of there and drop each end of the oppossing mains into the new header (you currently don't have a Header either).

Jack M

Here's the main on the other side. The radiators are all on long runs off this main. I think that the Main is so long that it acts as a heater, that or the slanted riser (45 degree) accomplishes this task.

Jack M

wider view

Fred

No Header, No Equalizer, No Hartford Loop, looks like about 3 places where fresh water can be added to the boiler. I'm not sure what the thinking was there?

Jack M

Fred said:

looks like about 3 places where fresh water can be added to the boiler.

those "places" may be the connections to and from the DHW coil. Then there's the LWCO, and cold tap for filling the boiler.

Fred

Jack M said:

Fred said:

looks like about 3 places where fresh water can be added to the boiler.

those "places" may be the connections to and from the DHW coil. Then there's the LWCO, and cold tap for filling the boiler.

OK, I do see a cut-out panel on the side of the boiler where I assume the Hot water coil is. That makes sense to me now.

Jack M

If the bull headed T and with the Main running in two directions is a problem (have not noticed an issue in 12 years) could the bull headed T be capped off on the right hand side (still feeding the old Main to the left) and a new riser added off the header for the orphaned (right) main. The right side would be left without a return.

Fred

If it is working reasonably well the way it is, I wouldn't touch it until you install a new boiler. When you do install a new boiler, I'd use both risers out of the boiler, like in the picture, tie those into the header, be it a standard Header, at least 24" above the water line, or a Drop header, then follow those connections with two risers , one up to each end that currently connects to that Tee and after that, add your Equalizer to the end of the Header. Neither Main would be left without a return. The return you have now may be a single common return for the main that goes in each direction but they both obviously currently return to the boiler. Steam currently goes in two directions and both directions currently return water.The only thing seperating the main, out of the Tee will do is prevent steam from slamming into the back wall of that Tee and pushing back into that angled riser before it finally turns in either direction to head down the main(s)

Jack M

Fred said:

When you do install a new boiler, I'd use both risers out of the boiler, like in the picture, tie those into the header, be it a standard Header, at least 24" above the water line, or a Drop header, then follow those connections with two risers , one up to each end that currently connects to that Tee and after that, add your Equalizer to the end of the Header. Neither Main would be left without a return. )

I now understand the conflict cause by the "T" with the split main. What both risers go to a drop header, then connect to the very end of the main running off the right side of the bullhead "T."
That main would is now sloping in the right direction and without the "T" (no more T just one main) the condensate would keep flowing on the loop around the chimney (with the flow of steam).
I'm still cannot visualize the riser to header to main connection
(the boiler can be moved).

Jamie Hall

I wouldn't worry about the arrangement of the mains. A T is a problem when flow comes in both ends of the top and out the leg, but the other way -- in the leg and splitting out both ways -- is not really a problem. Don't mess with it unless and until you need a new boiler. At least that's my opinion...

I'm still concerned about dropping the water line. As I have said before, piping kit or no piping kit, drop header or no drop header, the only reason to do it is aesthetics, and that, in my not so humble opinion, is a mighty poor reason.

Fred

In your drawing, you have one "B" riser going up from the Header and heading to the left. What you need are two "B" risers going up from the Header, one turning left (as it does in your drawing) and one heading right. How does the main that goes off of the Tee to the right currently drain back to the boiler? There has to be another drip or return on the end of that, elsewhere in the basement, because it doesn't look like it wraps around the chimney. Maybe a drawing of the current pipe configuration would help me usderstand what is going on there.

Jack M

In the ballpark?

Fred

That would work.

Jack M

Fred said:

IThere has to be another drip or return on the end of that, elsewhere in the basement,

No other drip. The system had twice as many radiators firing a coal boiler in the 1920's. When the coal system was replaced (60's?) some of the pipes stayed, and a few were added (indoor bathroom with a radiator!).
Patched holes the corners of rooms tell of radiator runs that no longer exist.
So this suggested configuration might mirror what existed before (?). Just guess on that.

Jack M

Jamie Hall said:

I
I'm still concerned about dropping the water line. As I have said before, piping kit or no piping kit, drop header or no drop header, the only reason to do it is aesthetics, and that, in my not so humble opinion, is a mighty poor reason.

I hear you. However I don't know what options there are. I'm guessing that modern boilers have a higher propensity to throw up wet steam if not matched perfectly. That old boiler is probably just hanging on.

Jack M

To keep the old water line the base spanner bar of the new boiler would need to be raised 17 inches off the basement floor
49" = 29" + 3" + 17"
That height puts lowest point of the main 20" above the water line. The spec calls for 28"

ChrisJ

Forget about the old water line, get rid of it.
It's gone, it no longer exists. Put the boiler on the floor, or up on a nice concrete pad, or even some normal sized blocks but not up in the air.

It looks like you have a fairly simple simple. Just drop the returns down to the floor, or an inch off of it and call it a day.


The boiler you have is up on blocks because the previous installer didn't know what he was doing and was afraid to make changes.

Jamie Hall

ChrisJ said:

Forget about the old water line, get rid of it.
It's gone, it no longer exists. Put the boiler on the floor, or up on a nice concrete pad, or even some normal sized blocks but not up in the air.

It looks like you have a fairly simple simple. Just drop the returns down to the floor, or an inch off of it and call it a day.


The boiler you have is up on blocks because the previous installer didn't know what he was doing and was afraid to make changes.

OH??? OK, I give up. I hope that there aren't any water seals on wet returns out there, but that's not my problem, is it.

ChrisJ

Jamie Hall said:

ChrisJ said:

Forget about the old water line, get rid of it.
It's gone, it no longer exists. Put the boiler on the floor, or up on a nice concrete pad, or even some normal sized blocks but not up in the air.

It looks like you have a fairly simple simple. Just drop the returns down to the floor, or an inch off of it and call it a day.


The boiler you have is up on blocks because the previous installer didn't know what he was doing and was afraid to make changes.

OH??? OK, I give up. I hope that there aren't any water seals on wet returns out there, but that's not my problem, is it.

Water seals on wet returns?
He's making new wet returns by lowering them to the floor. Right?

Or did I miss something because I don't recall telling him to raise the returns and make them dry.

KC_Jones

Unless Chris and I are both missing something you guys are seeing. The wet returns in question are currently about 4-6' long right at the boiler. From what the OP has said and what can be seen in the pictures this seems like a very straight forward situation. To the OP are there any other wet returns in the basement other than the ones shown in your boiler pictures? Is most if not all of the return piping up towards the ceiling and the only low wet return is that one right at the boiler?