New boiler- old pipes

krpurdy

Looking for some tips on what to do next! We had a new oil furnace steam boiler installed in spring- was a bit of an emergency replace as the old one cracked and started flooding the basement- so we didn't have much time to shop around.

The boiler / LWCO all behave as it should - except it doesn't seem to like the existing piping in the house. Its a one-pipe system with a return line but each radiator is a dead end, so water has to return through each steam pipe before it gets to the return line (not sure if that's normal). There are also 2 direct-to-radiator pipes from the boiler itself. In a nutshell, if we let the system run, it regularly over-fills and floods the pipes to the 1st floor radiators, and have wall-shaking water hammer, none of which we had previously with the old furnace (which was from the 90's so not even that old!). We have narrowed the cause of the flooding down to very slow return (it takes 1-2 hours for water to drip back into the boiler after it shuts off with the main inlet water turned off) Wondering also if maybe its because the new boiler pushes water into the pipes(not sure which way - back up the return line?) and the old one didn't.

The local service guys recommended we checked tilt on all radiators, replace/clean all the valves on the radiators. So that's done, but this hasn't fixed the slow return or water hammer (mostly in the wall up to the 2nd floor). We live far from any big cities and our local guys usually refer to this forum for ideas. I'd appreciate any suggestions. I've spent hours searching the forum - best suggestion so far might be that we have to have the return line cleaned, but since most of the radiators that flood aren't tied to the return line, I'm not sure that's the way to go? Thanks in advance

Here’s the new setup -its a Burnham.

ChrisJ

Out of curiosity, how clean is the boiler and it's water?

krpurdy

The water is super clean because we have to add a gallon or two every day when we run it (not since spring - this is prep for fall). When it was installed they added some purple cleaner, but it didn't last very long because we were always draining the tank. We don't see gunk or anything when draining (and we drain from what I was told is the return (the valve down below/behind the boiler - just got cutoff in the top photo)

Canucker

A gallon or two every day? Something isn't right, that's way too much. I think @ChrisJ steamer goes through less than a gallon per heating season. What pressure does it run at?

Jamie Hall

Hmm. Well, at least it looks as though the new boiler was piped correctly -- for a change!

But @Canucker is right on two counts: a gallon or two every day is way out of line. I start to worry (and look for leaks) when Cedric goes over a gallon a month -- and as has been mentioned, at least one of us uses about that in a year. So somewhere you are losing a lot of water, and you need to find out where. Second, he asked about pressure: the cutout should be less than a bit over 1.5 psi (if you have a standard pressuretrol, that's about as low as you can go). Anything over that will cause some problems.

As a passing comment -- and it may have to do with the water use -- there is no need to "drain the tank". In fact, it is harmful. If you have a float type low water cutoff, that should be blown down -- perhaps a gallon or less -- once a week or so; otherwise, leave it alone.

The slow return is a concern. Is this a wet return to which you are referring? That is, a pipe which is at or near floor level, and which is connected to the steam main with a vertical drip? They do get clogged on occasion, so if it's not too hard to do you might try flushing it out. If it is buried below the floor anywhere, it also can have hidden leaks -- another possible concern for you water use.

Now you mention that the boiler pushes water up into the mains. The should never happen, particularly with your decent near boiler piping. Can you make a sketch of the whole system -- all the piping, with the location of any main vents? That might help figuring out what is happening. Your water hammer may be related to that.

mattmia2

They could have disturbed the pitch of the supply pipes so they no longer return the condensate the way they are supposed to.

There could be oil on the surface of the water that was note skimmed off from the new installation, that will cause the water to boil more violently and push water up in to the piping. They need to open a tapping near the water line and let the oil from new piping drain off after it has run a bit, likely multiple times to get it all.

What is a lot more likely is that the new boiler has a lower water line than the old boiler did (or the old boiler had a false water line created in the return piping that was removed but not replaced) that was keeping some part of the return under water so that steam did not bypass it and the water line was made too low on the new install. High pressure will make this sort of problem worse or in some setups create the problem altogether. The pressure should be around 1-1.5 psig or lower. if it is several psig that could be the problem in itself.

It could a combination of all these things. The fact that it was ok with the old boiler and that the new piping looks to be more or less correct without knowing about the rest of the system leads me to these being the 3 likely possibilities.

krpurdy

Thanks all. I think I need to clarify. If I close the water input to the boiler no water is lost, the water all comes back if you wait long enough, so I'm pretty sure the system is closed (no leaks) .The problem is the system will then only turn back on once the LWCO is satisfied, which takes about 2 hours, because the return is so slow!

If I have the water line open (so the LWCO can turn on the auto- water feed), then the water-feed kicks in (even with the slowest setting!) way before the water in the pipes returns to the boiler from the return line - this leads to overfilling, flooding of the radiators, and water gushing out the 1st floor vents. The boiler is now over-full because water was added by auto-fill AND water from the pipes is still returning. Then we have to drain the extra fill. So, the slow-return causes the the auto-feed kicks in. If we were OK with the system only turning on once every 2h or so, this'd be no problem, but that doesn't keep the house warm, sadly, we have to speed up the return somehow, I think?

Standard Pressuretrol: Pressure is set between 1.5 and 2 psi.

I attach a drawing - i'm pretty sure I can not draw this accurately. The return line- I think is wet - it is just below the main steam lines (there are 2 separate ones) and tips vertical to return to the boiler (you can see it in the photo).

Jamie Hall

That's a dry return. It does return condensate, but it is not full of condensate. Nor is it likely to be plugged; dry returns almost never are. However, you could have some plugging at the bottom of the return, just where it goes into the boiler.

My guess just for the moment is going to be that the pitch on the lines got messed up. If your diagram is reasonably accurate, the steam mains are intended to pitch down away from the boiler to the return, and then the return must pitch down towards the boiler. Check that.

Until you get the slow return straightened out, though, you'll continue to have problems. Every time you overfill the boiler, you get water up in the steam lines -- and that is going to hammer, regardless of what else is right or wrong.

mattmia2

It is a dry return because it is above the water line. In that case it looks like it is a drip to return the condensate from a low spot in the main where the main couldn't be sloped to return the condensate to the boiler. Some larger pictures of that header would help a lot, there may be some incorrect fittings or some missing detail that is preventing the water from returning and making the steam push it out in to the system.

Is the water line in the sight glass stable while it is steaming or does it surge up and down a lot?

krpurdy

@mattmia2 - I would say the water line bounce quite a bit while it’s steaming.
@Jamie Hall the pitch on the steam pipes is down as you leave the boiler to the return. They go back up again only to the radiators. My drawing is just bad.

I saw a mention the pressure should be 1-1.5 psi. With 1.8 or so is that too high? Originally I think we put it there to make sure it pushed to the 2nd floor- but I can’t remember.

If its a dry return, then would you say the main steam pipes are what is preventing the water return?

Here is a higher resolution picture of the main piping out of the boiler - not sure exactly what to focus in on. Also a picture of the piping behind the boiler?

ChrisJ

Draining water isn't going to get oil and junk that's floating on top of the water and that's what can cause the issues you're seeing.

Can we see a clear picture of the water in the gauge glass?

krpurdy

looking for oil or gunk on the water - looks pretty clean - no film from what I can tell, but I hear you .

Jamie Hall

The way these things work is -- in your situation -- the steam main or mains slope downward to the ends, where there is a connection to the dry return which, in turn, slopes on downward until it gets to the boiler, where it drops down to get to the return inlet on the boiler. The single lines (hence one pipe steam) to the radiators have to slope up away from the steam main.

Now... there really are only two ways that the returns can be slow, if you think about it. Either the pipe pitches aren't adequate or are even the wrong way, or there is a partial clog -- which will almost always be in a section of pipe below the water line of the boiler (almost always... rags have been known to find their way into new piping...).

Usually -- but, perversely, not always -- an inadequate or even reverse pipe pitch will let you know all about it with water hammer. But, as I say, not always, so it is worth going over the full length of the steam mains and the dry returns to make sure that they do, in fact, slope adequately in the right direction.

I can't see from the photos, but does there happen to be a drain valve at or near where the return drops down to the level of the equalizer connection? If so, you could open that -- water should come out quite freely.

BobC

The best way to find a dip in a length of pipe is to stretch a string beside it, any dip will become apparent.

Bob

krpurdy

Alright- I’m getting the idea that maybe my main line is not pitched down enough, Will triple check.

All the drains near boiler ( there are 2 - one is near in photo and one is far- the far one connects to return more directly The near one just goes to bottom of boiler) flow free and clear. Still learning this stuff- trying to understand how return condensate actually gets to boiler- looks like it has to push up over the diagonal pipe in the back?
From everyone’s comments I’m Starting to think the trouble is where mains connect to return line. If water is stuck there... it might be the problem. Probably time to call in the service guys.

mattmia2

The surging is a huge part of your problem, the boiler needs to be skimmed until it stops doing that. If that much water has been forced up in to the system it will have carried oil with it so it will likely need to be done a few times as that oil gets returned to the boiler by the condensate. It is possible that the slow return is just the large quantity of water in the radiators slowly draining out of the radiators and back to the boiler, but look at the pitch of the pipes and look for any valves that might be closed as well.

mattmia2

A couple pictures that how how that "front" pipe that the diagonal pipe ties in to the boiler and header would also help

ChrisJ

mattmia2 said:

The surging is a huge part of your problem, the boiler needs to be skimmed until it stops doing that. If that much water has been forced up in to the system it will have carried oil with it so it will likely need to be done a few times as that oil gets returned to the boiler by the condensate. It is possible that the slow return is just the large quantity of water in the radiators slowly draining out of the radiators and back to the boiler, but look at the pitch of the pipes and look for any valves that might be closed as well.

That's why I keep thinking water issue.

Water doesn't leave very fast via steam. It takes a long time.

krpurdy

OK. I think I have a game plan. Will do skimming.

The only other thing I can think of to ask is if its possible that water is getting pushed backwards up the dry-return while the boiler's firing. Given the return pipe height, I'd think if water is getting pushed up, it'd go that way first, as its lower - it makes sense with which radiator floods first. Asking because every time the boiler turns on the water level goes low after about the 2nd fire (just when its starting to heat the house) and I can't believe its all going to steam. Is that plausible, or am I crazy? Not that knowing would fix the problem, still going to skim/ check tilt.

mattmia2

Can you show us some better, further back, and higher resolution pictures of the near boiler piping so we can see where the dry return ties in and what it connects to?

In order for water to push from the boiler in to the dry return, it would have to build enough pressure to lift a column of water that high(another reason why settings over 1 psig or so on a boiler are bad). It is more likely coming from the boiler in to the main as liquid water then flowing in to the return because of the surging than being pushed out the return.

mattmia2

I see another picture in the middle that sort of shows that diagonal pipe. The return near the ceiling drops down to the floor, connects to that diagonal pipe at the floor, then goes up to the return? It looks like it is a hartford loop, but it looks like it is protecting a return that is high enough it could allow the water to flow or be siphoned out of the boiler.

I can't see very well where that return drops to the floor. Does it also connect to a pipe in the floor?

krpurdy

Problem with photos of the Hartford loop is there is a wall in the way. Here are 3, 2 from the left which is the pipe up to steam and one from the right which shows the return line.


Being paranoid I measured the height of the loop max to the water level. There's supposed to be 2 inches from water level down to the loop pipe - I don't know if that's top of pipe or bottom of pipe, so it seems a bit short unless I raise the water level default. (the pipes all came from Burnham in a kit so I'm assuming its default OK).

Jamie Hall

It's a little... um... unusual. But, you know, I think it should work fine. What I don't see, though, and wish I did, is a valve at the bottom end of the diagonal, which would allow you to see if the drop from the return to that point is clogged. There does seem to be a union, though, and I expect one could open that and see if it flowed freely...

krpurdy

@Jamie Hall - yea, there is a valve there (top picture), I have a hose connected to it now because I was checking.. flows freely.. can't find a clog anywhere, which I guess is good, but makes the mystery more fun.

krpurdy

Eureka!  Found a small dip in the return line- propped it up with 2x4's. New install must have kicked the end of the pipe by the furnace up 1/4 to 1/2 inch. Now its purring like a kitty. Now to figure out how to skim the tank in the absence of a way to bypass the auto-filler. Thanks for all the advice

Jamie Hall

There you go. It had to be something like that!

dopey27177

The drawing shows a counter-flow piped steam system. It appears that all the condensate from all the radiators come down the steam supply line.

Steam and condensate do not like each other. The steam supplying the radiators causes the retardation of the condensate return.

If this was an original installation the steam pipe would have over sized to permit the condensate to return with out time lag and banging.

Enclosed is a method to allow condensate to return with time lag.

It is not a cheap fix but is a permanent fix.

See enclosure.

Jake

clammy

Aside from a possible skimming and wanding ,I think I would have separated your 2 mains and removed the one that ties into your other riser ( get rid of that 45 take off ) and piped a seperate tee in from that main . The 2 90 are also a spot for condensate to sit . Each main should have a seperate tee off the header unless the one is only connected to a small edr if so then just a drip off that riser ,like where the elbow is before going vertical would help both in allowing carry over to drop into the return instead of being forced upward or trying to drain back . Peace and good luck clammy