Peerless SC Steam Boiler - recommissioning after sitting for 6 yrs

Ivo

New to the forum and new to steam. Many thanks in advance for any help.

Bought a nice old money pit in Vermont that was equipped with a Peerless SC series steam boiler with a single pipe distribution system. The unit was installed sometime early 2000 but has been sitting for 6 heating seasons empty and off (house was vacant and winterized). Several attempts at getting my oil supplier to go over thing with a service tech has been futile. Every guy they send out knows nothing about steam or hydronics so I don't let them learn on my nickel. One guy did service the oil burner assembly and dry fire the unit so that part is in good working order.

I am experienced in hot water systems but never worked on steam systems so after studying the Peerless manual and such feel fairly confident I can fire the unit up but looking for any advice/tips on recommissioning a piece of equipment that has been sitting. The other question I have is should I upgrade any of the controls at this time. The unit was equipped with MM 101A feeder but that was seized so I replaced it with a VXT-120 plus new pressure reducing valve and pressure relief valve. I filled the unit and no leaks.

Should I change out the MM67 or leave it alone if its working?

Also, I do not wish to use the DHW hookup at this time, so is it safe to just leave the circuit open?

Many thanks!

Jeff

nicholas bonham-carter

Looks like the pressuretrol may be set too high, maybe to compensate for inadequate main venting. Clean the pigtail, and be prepared to give it a good cleaning if the water is cloudy with rust.
Test the MM-67 frequently at first, to make sure it can do its job.--NBC

Jamie Hall

The MM67 is fine, but as @nicholas bonham-carter said, keep an eye on it and test it until you're sure of it.

As for starting the rest of the system... well, steam is pretty simple and, by and large it either works or doesn't. The way to proceed is to make sure you have enough water in the boiler -- at least half way up the glass -- and that it's staying there. Then fire it up. I won't go so far as to say the built in gauge is useless, but it requires some thought. Note what it says the pressure is when it is cold, and use that as a zero and compare pressure to that when the system is starting. After a bit, the boiler will start making steam -- at which point a helper, while not mandatory, is useful, because you want to go around everywhere and see that steam is getting to the radiators (may take a while 10 to 15 minutes or more) but also that it isn't leaking anywhere. Meanwhile you are at the boiler, and if you see the water level dropping more than say 3 inches, or the pressure rising more than two or three pounds, or you get a yell from your helper that there's steam all over the place, you want to be able to shut the thing off.

Once you get to that point, you still want to keep an eye on the water level -- it should come back to where it was when you turn the boiler off, although that may take 10 minutes sometimes -- and start to explore the system. Does it heat reasonably quickly to the farthest radiators? Do the radiators heat, but not overheat the spaces? Do you year water hammer -- loud bangs -- in the piping? Etc. All these things can be fixed, and rather easily in most cases. But get the thing running to get yourself some heat first.

Oh -- and get yourself the book "We Got Steam Heat" from the store on this site and, if you are inclined to really learn how the system runs, "The Lost Art of Steam Heating", also on this site.

Ivo

Thanks NBC. I am using Peerless' guide on one pipe systems to guide me along. Will check on the main vent in the morning and see how the installer configured the system. Would it be wise to change out to a vaporstat?

https://www.peerlessboilers.com/wp-content/uploads/2018/01/OnePipeSteam.pdf

Cleaning - any advice on that. Just watching some videos on it seems to indicate flushing the unit out til water runs clean?

Ivo

Thanks Jamie,
Will get the book. Hoping to keep this unit running for a while.
Jeff

Jamie Hall

I forgot to mention one thing, because I thought it was obvious... maybe not. Check the flue and chimney for condition and blockage!

EBEBRATT-Ed

I would clean the pigtail on the pressure control a others have mentioned. The MM 67 they recomend replacement every 10 years. I think I would take the drain valve flange off and clean what you can up inside the control if only because it has been sitting.

One you get the boiler running make sure the pressure control will shut the burne down by lowering and raising the setting on the pressure control. Also test the MM 67 by blowing it down when the burner is running and make sure it shuts the burner off.

Test it every couple of days for a week or so.

I would also while the burner is running remove one of the yellow wires to the cad cell eye and make sure the burner goes off on lockout. Should shut down in 45 seconds or less.

The wire is low voltage. After the burner shuts down replace the wire and push the reset button to restart the burner

those 3 safety's are important you want to make sure they work

BobC

Jamie's comment about checking the chimney and flue is a good one. A neighbor once had the gas company in because the boiler smelled funny.

They found a dead seagull in the chimney that was blocking it, this could happen with any large bird so it's something to watch out for.

Bob

JUGHNE

IIWM, before investing any money in the boiler, I would flood the water level up to the ceiling level.
Let sit for an hour to see if any leaks develop.

Winterizing is not always 100% effective, even for steam.

Ivo

Thanks for all the input. I did flood the unit and left it sit overnight and no leaks. Daylight up the chimney so that is clear.

I can not locate a main vent anywhere - might this be why the pressuretrol is set high? Have gone over all the piping in the basement and do not see a vent anywhere.

Here is a pic of the piping around the boiler:



Thanks
Jeff

mattmia2

There isn't a horror reaction for that post. There is a disagree, but that isn't quite the right reaction. If you have to limp along with it, maybe give it a try, but if you want to make it work right you should plan on replacing it. It should be black iron, the header needs to be further above the boiler, and the second tapping probably needs to connect to the header.

Ivo

I am aware of the copper/vs issue. Hoping not to open a can of worms here for this season. I assume the height of the header was limited by the existing distribution piping since most everything seems to be original. It is a bit of bowl of spaghetti up there - mostly black pipe.

Flushed the unit and it water ran clear. Not much gunk.

mattmia2

Look in to a drop header if there isn't clearance. The header needs a certain height above the water line.

Jamie Hall

Well... it will probably heat. Steam is amazingly forgiving. It will probably bang. It may use more fuel than it really should (but not to worry -- not that much more). Then you can think about redoing it next spring and summer.

Ivo

Thanks for the input!

Fired her up today and HEAT! All radiators appear to have heated up evenly and in about an hour.

Tested the MM 67 to make sure it was working with the new VXT-120. All good. Pressuretrol appears to work but do not know if it is accurately reading the boiler pressure. The internal siphon gauge seems to be on the fritz - currently stuck at 30psi. Should I replace the gauge with a new one or install a low pressure gauge in conjunction with pressuretrol - or both. The header is 25" above the min water line of the boiler.

As previously noted, there are no vents on the main or the risers. I drew out the piping diagram here:



Should I install vents and where should I install them? If so, what make/model is recommended.

Vents on the radiators are working but look pretty vintage - recommendations are replacing these?

I would like the system to be operating as efficiently and safely as possible. Would a vaporstat be a worthwhile investment? Any other recommendations?

Should the main be insulated? Currently only the risers are.

Pretty impressed with the heating power of steam - house is roasty toasty.

Jeff

pecmsg

That boiler requires a 0 - 30 PSI gauge. Install a 0 - 3 as a use gauge

Jamie Hall

pecmsg said:

That boiler requires a 0 - 30 PSI gauge. Install a 0 - 3 as a use gauge

Even if the 0 to 30 is busted. Leave it.

Once you get the 0 to 3 on there, you can check the pressuretrol settings. Most single pipe steam systems -- if the pressuretrol is even remotely accurate -- really don't need the better repeatability of the vapourstats, nor do they benefit much from keeping the pressure below 1.5 psi. Therefore, since vapourstats are pricey, I'd probably not bother.

On the vents. All the locations you have pointed to need vents, at least somewhere in the vicinity. Depending on the length and diameter, I'd suggest either Gorton #1s or #2s. I'd leave the radiator vents alone until you get those four new vents on, as they will change the way steam is distributed. Then you can start altering radiator vents -- if you need to. If it ain't broke, though, don't fix it.

And steam heat is pretty nice, isn't it? And simple!

pecmsg

Jamie Hall said:

pecmsg said:

That boiler requires a 0 - 30 PSI gauge. Install a 0 - 3 as a use gauge

Even if the 0 to 30 is busted. Leave it.

Once you get the 0 to 3 on there, you can check the pressuretrol settings. Most single pipe steam systems -- if the pressuretrol is even remotely accurate -- really don't need the better repeatability of the vapourstats, nor do they benefit much from keeping the pressure below 1.5 psi. Therefore, since vapourstats are pricey, I'd probably not bother.

On the vents. All the locations you have pointed to need vents, at least somewhere in the vicinity. Depending on the length and diameter, I'd suggest either Gorton #1s or #2s. I'd leave the radiator vents alone until you get those four new vents on, as they will change the way steam is distributed. Then you can start altering radiator vents -- if you need to. If it ain't broke, though, don't fix it.

And steam heat is pretty nice, isn't it? And simple!

If hes going thru the trouble of installing a LP Gauge also get a operating HP gauge. They do come in handy from time to time!

Ivo

Discovered that the pressuretrol was not working properly. would not cut in when the pressure came down so I replaced it. Installed a LP gauge next to the new (spare) pressuretrol and the the set the cut in to .5 and the Diff was set at 1. The boiler ran until the pressure gauge read 2.5psi and then cut off. Comes back on when it reaches .5 - I assume that is how it suppose to work. The old pressuretrol was set at 2 with the Diff set at 1. When I set the new one to this the boiler will run up to 3 or so and stay there until setpoint is reach and the boiler shuts down.

So where should I leave the pressuretrol set at. From what I have been reading, the PT should not be the controlling the cycle, that is the thermostats job.

So why is the system operating at such high pressure - is this the case of a bad design or pipe layout job when they retrofit? How do I bring the operating pressure down and other than burning through oil, any dangers running at this pressure.

Also, does it effect anything if I opt to close off several radiators on the 2nd floor since the space is not be used?

Thanks again

ethicalpaul

Put the pressuretrol at its lowest settings.

A lack of main venting will cause pressure to rise early in a heating cycle.

An oversize boiler will cause pressure to rise just about anytime.

Closing off radiators will effectively make a boiler more oversized, so that might not be a way to go.

Ivo

Thanks Paul.

Ordered some Gorten #1's for venting the mains and will see how that affect the system pressure.

Questions:
Should the mains all be insulated back to the header?

All radiators have heat and heat evenly from what I can tell.

Jamie Hall

The mains should be insulated -- and so should the header and risers.

mattmia2

You could measure all your radiation to figure out the EDR connected o it and compare it to the boiler then see if the manufacturer recommends downfiring the boiler to a point that more closely matches the connected EDR then yo could have the next oil burner tech that services it downfire it to that rate through nozzle selection and pressure settings. It is important that when it is serviced it is set up to fire at the rate that the system was designed for.

dabrakeman

After doing all the safety checks previously mentioned you really should get the main venting in before assessing much else regarding pressures and run times. How long is the main? Probably should put a Gorton #2 on that first end at least. The Gorton #2 has more than 3 times the vent rate of the Gorton #1 but at about 2 1/2 times the price. If you have room to make an antler you can mix and match as you later see fit. If not much room but can put one good vent in then use the Gorton #2 or a Bigmouth. Is there any kind of fitting there already? Don't know how easy your risers are to get to but would make that a distant second priority to do in the Spring if looks like a real chore. I for one as a homeowner don't really like cranking on my old pipes too much when Winter is bearing down on us... (particularly if you don't know a good steam pro is handy). Insulating is easy enough to do.

Ivo

Thanks Jamie - will do.

Great idea Matt, now that I have Don's book I am looking forward to working out those calculation and seeing where the boiler size should be.

dabrakeman - some of the mains were redone in copper and the vents will be easy to install but some of the mains are black pipe and definitely original. I agree that wrenching on that old stuff this time of year is nerve racking. Probably wait til end of heating season to work on this segments.

Thanks everyone for the input. House is nice and toasty and boiler appears to be functioning normally atm.

Jeff

Ivo

One last one - I noticed on Supplyhouse there are Dresser-style coupling for low pressure steam - I assume this are good to use. Thinking this would make it easy to install vents at the end of several iron pipe mains where the previous fitter failed to account for vents. Not have to wench or hammer on old pipes with asbestos wrapping appeals to me.