Priorities?

danmayer175

With help from all the great info on this site, I think I've finally identified a number of issues with my 1-pipe steam system, but I need help putting them in order. 1 thing at a time. The main problems I have are water hammer and huffing at the rads, and some weird cycles (1-second cutouts) , especially on long boils when it's really cold. And water level issues that have made it impossible to use an automatic feeder - which isn't the end of the world, but indicative of other issues.

Burnham PV74 SBPT oil-fired steam boiler installed in 1996 with the right components. I have all the manuals and all the model numbers match spec. The usual P404A pressuretrol, a 1-30 psi gauge, CG450 probe LWCO, etc. But also a MM67 float LWCO. Most of the piping is from circa 1936, but some of the near-boiler piping was redone in 1996.

Potential problems I've identified in what I think is the order of priority?

1 - Float LWCO and gauge are 3-1/4" above prescribed level. So boiler is always overfilled contributing to wet steam and funky cutouts?

2 - I doubt the pressuretrol is functioning. It's set as low as it goes. 5 psi develops on most fires. So, clean out pig tail, and maybe add a 0-5 psi gauge to get more accurate readings?

3 - There is one branch riser "uphill" from the main riser (there's a tee at top of main riser). So that branch returns into the main. It can be re-piped to hit main downhill from riser but it's chasing slope and will have to elbow into side of main, not drop into top like other branches.

4 - After insulating the main and taking one radiator off the system, it's a bit oversized. Boiler plate says 488 sqt ft EDR. My radiator calculations put me at 355 sq ft. Not sure it's a problem or what adjustment would even be? Issues worsened slightly when I took radiator off a year ago.

4 - Header is not far enough above close nipple - only 14" center to center. Worth fixing?

5 - Header is dead level - not sloped back to equalizer. So the condensate returning from the mis-placed branch has no desire to head back to equalizer.

6 - I have a Hartford loop now - close nipple enters equalizer with 2 inches of water over top. But if I get the boiler to manufacturers water level, I'll have a "GiffHart loop" with NWL centered at close nipple elevation. My theory is 1996 installers knew enough to be dangerous and "fixed" the GiffHart situation by raising water level in boiler?

7 - The automatic feeder (which is now shutoff) was calling for water on every firing. Hopeful this resolves itself with water level correction, but could be sign of pressure or wet return problems?

I'm hoping to avoid the (expensive) near boiler piping fixes until everything else is tweaked and I'm certain they're necessary.

Neild5

#2 should be your first task, it is also the least expensive and easiest. For the rest, can we see pictures of the boiler from multiple directions?

KC_Jones

1. Unless the boiler pipe size is really really wrong, I don't see this contributing to wet steam or any other issues you are having. Now if the piping is undersized, or otherwise quite bad, that's a different story. Also, when was the last time the float LWCO was disassembled and serviced? It should be flushed regularly, but it needs disassembled and cleaned as well. I don't have the manual in front of me, but they do have recommended service intervals.
2. Adding a low pressure gauge isn't a bad idea to understand how things are actually running. the 0-30 aren't really capable of working properly at the bottom of the range where steam operates. Definitely clean the pigtail.
3. I don't really understand this. A branch off the main is supposed to run uphill from the main and the condensate return back to the main through the same pipe. The way I read your description it sounds correct.
4. You aren't a bit oversized. I'll run the numbers so you get an idea. The 488 is after the gross output is divided by 1.33 for pickup. The full output of the boiler is 649. Using that against your system of 355, you end up with a pickup factor of 83%, so you really are a lot oversized. This will only matter when the boiler fails and needs replaced. I am curious why you took a radiator out?
5. I doubt that's much of an issue, it should slope yes, but the amount of water a dead level header can hold is miniscule to the point of being meaningless.
6. See my answer in 1 above.
7. If it's calling for water it's because the LWCO is asking for it. That's not a feeder problem, it's something else. Are you confident the LWCO is operating correctly? If it is, why is all the water leaving the boiler on every cycle? That's what needs to be looked at.

As far as priority, I'd find out why the water is leaving the boiler on every firing, that seems like it's happening based on your description, but maybe I am misunderstanding what you have going on. To be clear, if the feeder is calling that has nothing to do with high water level, it's about the range the LWCO operates in. Lower it, and you just shift the range down, if the water is still leaving the boiler, you end up in the same boat. That is why I would start with why the water is leaving the boiler.

I wouldn't change boiler piping on a 28 year old boiler. If it needs re-piped, just replace it. A majority of the cost of a new boiler is in the piping. So if you re-pipe it, then it fails in 2-4 years, you will just be paying that expense all over again in a short time frame.

danmayer175

• 1 - Pipe sizing looks good, I think. Photo below will help.

• 1 - The float definitely needs to be disassembled. I'll start with that and the pigtail.

3 - See photo below. Condensate from 2 radiators never sees the wet return. Comes right back to the header. Oddly there is very little noise coming from that branch.

4 - So I take it there's no way to "downsize" existing boiler? Just replace at appropriate size one day. Radiator stood in the way of my wife's dream kitchen. Wasn't sure it would work out, but it has.

7 - I don't think there's a lot of water leaving?. But I'm not at all sure the LWCO is working correctly. I've been manually feeding it for years. No meter so I'm not sure of volume, but after a cutout and cooldown I add about 2" of water in the sight glass and it's good for another 10 days. If the boiler's got enough water, but drops low enough to ask for more I think I have big level fluctuations during a boil. My best guess is there's too much pressure?

KC_Jones

That definitely clarifies some things.

The main feeding 2 radiators should have been set up as a counterflow main with a drip return back to the boiler. If you ever replace I'd have that as an upgrade on the piping.

The header is quite low and I could see getting excess water in there, but with that extremely long riser to the main, I'd have a hard time believing water is leaving through that.

2" in 10 days, you have a leak, somewhere, either steam or a return line, something. That definitely seems like excess usage to me.

Downsizing a boiler could be done, but not a huge amount and no contractor is going to do it unless the manufacturer "blesses" it first. Since you are on oil you also need to find a very competent burner tech to be able to down fire and run a proper combustion analysis. That's something that should be done every other year at least anyway.

Ah the dream kitchen, we've seen that here a ton of times. Hopefully you found a creative way to heat it otherwise. In floor radiant running off the water in the boiler would have been super nice, but based on that picture it doesn't look like you went that route.

Jamie Hall

#2 is certainly your first project.

The water level (#1) is a curious one — although Cedric is set up in much the same way. What I would do — and have done — is try running the boiler with the water level cold set high enough so that on firing it doesn't trip the LWCO, provided only that the cold level is stil inside the sight glass (which it probably will be). If this doesn't give a wet steam problem, I'd just live with it as it is. It will do no other harm. I don't see a photo showing how the MM67 is piped. It may be an easy repipe job — or it could be a real nuisance.

#3 — if that runout heats and doesn't bang, leave it be.

danmayer175

Here's the piping to the gauge and MM67 with 3" dog leg. There's also a probe CG450 and both are tied into burner. I suspect the installer set them up with float as primary and probe as a backup.

dabrakeman

I'd suspect that counterflow main heading toward the two radiators is the primary source of wet steam in your system. It needs its own independent drip so its' condensate doesn't become part of the conflux at the top of the riser. Huffing and banging usually related back to a pitch problem in one of the source pipes.

Long Beach Ed

The old "bullheaded riser." That installation calls for two takeoffs from the header; one for each main. Otherwise, as brakeman says, the condensate returning from one is fighting down the riser, wetting the steam supply and causing mayhem.

Or, as brakeman says, a separate "drip" for the counterflow main. I prefer separate takeoffs.

But it's old stuff. Figure out the low water cutoff and leave the piping alone, like Jamie suggests.

109A_5

The camera angle and position is poor but I bet the M&M 67 would do a good job of maintaining the actual proper water level for the boiler, which is about 1/2 way between the boiler's actual tappings (not where your sight glass is). M&M 67 has that level line marked in the casting, which in a normal installation is usually just above the minimum water level but not at an optimum level. In your case, with your sight glass where it is, it would always look low on the sight glass since the sight glass is set up wrong for the boiler. The brief interruption maybe the LWCO but the switch usually has a slight dead band that calls for water before it shuts the burner down. Or you are tripping on pressure. This interruption may help with the oversize boiler thing but probably too short in duration.

They built a condensate dam by putting a reducer here.

I'd get the pressure under control for a start.

danmayer175

I suppose I can't draw any conclusions until I verify LWCO and pressure trol are working properly. But hypothetically - if there's too much pressure, would dropping water level to recommended NWL help? By making more room for steam?

109A_5

" if there's too much pressure, would dropping water level to recommended NWL help? By making more room for steam "

No, but it may make the steam drier, if wet steam is actually a problem, as someone else stated that riser is quite tall.