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Joined on November 14, 2009

Last Post on July 16, 2014

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@ March 8, 2012 11:12 PM in Repipe for water hammer

for the feedback, Jamie. Yeah, it is amazing the difference an inch or two can make. The drawing isn't quite to scale, where the sloping return ties in is only 15" or so above the floor so it's definitely wet. I used a mechanic's stethoscope to listen for the hammer (more of a tapping, actually) along that sloping return, and it was most pronounced around the tee at the water line.

I figure when the Dead Men piped this back in 1890, the water line on the original coal-fired boiler was a lot higher than it is today. It's probably just coincidence that the current boiler's water line just happens to be at that tee. I wonder if that whole sloping return used to be wet, since the initial vertical drop on the south wall is more than the 28" 'A' dimension.

Repipe for water hammer

@ March 8, 2012 6:36 PM in Repipe for water hammer

I have a water hammer problem that I'm pretty sure I know how to fix, but would like to get a second opinion from the folks here. Here's the situation (sketch attached):

The return line off of the main on the south wall of the house initially drops 34" from the main, then traverses the full length of the west wall with about a 1/2" per foot slope, then again about 10 feet on the north wall before it ties into a vertical return pipe midway down the main on the north wall and returns to the boiler.

The return line off of the end of the north wall main ties into the sloping return pipe on the east wall about 32" from the floor, which coincidentally happens to be where the water line is on the new boiler. I'm getting water hammer in this line midway thru the cycle, and I'm guessing that the water line isn't high enough at that point to flood the tee, so there are two steam paths into a what's become a partially dry return. If I raise the water level in the boiler an inch or two the problem subsides.

My plan is to repipe the return on the north wall main so that it drops to floor level before tying into the wet return. Am I on the right track here, or should I do something else?


If you don't mind a little math

@ February 19, 2012 8:51 PM in Single Steam Pipe Venting - Sizing

spend ten bucks at the shop here and get a copy of this:

Balancing Steam Systems Using A Vent Capacity Chart

Oops, it's the other way

@ February 19, 2012 10:46 AM in Cycleguard on Smith boiler preventing radiators from heating

Sorry about that, I mixed up the product names. Should have read replaced CycleGuard with SafeGuard, for the same reasons you're replacing yours. I found that every time it cut off the burner for 90 seconds it took a couple of minutes to rebuild the head of steam.

The existing probe

@ February 18, 2012 11:08 AM in Cycleguard on Smith boiler preventing radiators from heating

can be used with the Cycleguard. I replaced my SafeGuard with a CycleGuard more than two years ago. Removed the SafeGuard probe to compare with the CycleGuard , found the probes were identical, so I put the SafeGuard probe back in and put the new CycleGuard probe away as a spare. Works fine.

Radiator enclosures

@ October 21, 2011 7:29 AM in Radiator enclosures

After reading the Radiator Enclosures article in the Library here, I'm interested in constructing a few enclosures for our 1-pipe steam radiators to increase their efficiency.  In the first example,marked "Deduct 10%", the article is unclear on a couple of points and I'm hoping someone here can  answer a few questions: 
1. What is the "B" dimension for a 36-39" tall radiator?
2. How far above the top of the radiator should the board extend? 
3. Is the board supposed to enclose the radiator on the sides as well as across the front?
4. Will it help, hurt, or make no difference if I put reflective foil behind the radiator?

If someone has built covers in this style, I'd love to see some photos.


Firing rate - ratings versus actual

@ April 21, 2011 1:42 PM in Firing rate - ratings versus actual

I have a Utica oil-fired steamer with a 1.50 GPH @ 140 PSI nozzle. The service tech confirmed the actual nozzle size and operating pressure. I have an hour meter installed on the boiler, and track usage when the tank is filled. In 9 fills over the last two seasons, the calculated actual flow rate has been between 1.67 and 1.96 GPH, with the majority in the 1.75 GPH range.

Are these normal deviations? I don't expect it to hit 1.50 all the time, but if it's consistently 0.25 higher than that, does that indicate a problem or something to be checked?


Suspension boiler

@ March 5, 2011 9:49 AM in Suspension boiler

A friend is having a new basement slab poured. Here's a pic of how they got the boiler and hot water heaters out of the way.


@ February 11, 2011 6:49 AM in How low can you go?

On the L408J1009 vaporstat, R-B are normally-closed switch contacts, R-W are normally-open. So on pressure rise, the switch action will break R-B and make R-W. R-B are the contacts used in a typical line voltage installation where the vaporstat interrupts the burner power circuit.

Time delay relay

@ February 10, 2011 6:49 AM in How low can you go?

Hi Steve,

Like you, I have my system running at very low pressure, 1 to 1.5 ounces, and the pressure doesn't start to increase until near the end of a recovery from setback. I'm also of the opinion that continuing to fire once the pressure gets above a certain point is just wasted fuel. In my case, I have the vaporstat set to cut out at 3.5 ounces and cut-in at a slight negative pressure, around -0.5 oz.

The trouble I ran into was that when the vaporstat trips on pressure, it cuts back in after only 30 seconds or so. So I added a time delay relay that keeps the burner off for 20 minutes after the vaporstat cuts out. This lets the latent heat do its thing. It's been in place since last March and so far there has yet to be a cycle where the flywheel effect failed to "coast" to the thermostat setpoint. The average time for my system to go from "cut-out" to "setpoint reached" averages around 10 minutes.

I posted a couple of wiring diagrams, one for 24V and one for line voltage in this thread:

Both versions are designed to consume no power until the vaporstat cuts out, and the vaporstat is wired to the make-on-cutout side (R-W) of the switch rather than the break-on-cutout (R-B) side. I implemented the 24V version, because I didn't want to mess around with line voltage if I didn't have to, and also because I was able to get the 24V supply voltage from the burner control.

An off-the-deep-end alternative, and other thoughts

@ January 20, 2011 8:14 AM in Advice on vaporstat?


I'm not aware of any other low pressure mechanical controls out there that do what a vaporstat does (not at that price point at least). Depending on how badly you've caught the "steam enthusiast" bug, you could go off the deep end and venture into the electrical control arena.

I've installed a 0-3 PSI, 4-20ma pressure transmitter on a pigtail, wired to (relatively) inexpensive I/O (, which in turn is connected to a PC that is running software I wrote to record the pressure, indoor and outdoor temps, far rad temp, tankless coil outlet and tempered temps on a continuous basis. Next season I am looking at writing some more code and adding I/O to use the pressure transmitter as an operating control, replacing the vaporstat and the mechanical relay that's in place now.


The WIKA 0-3 PSI gauge from is fine for steam, since the gauge is installed on a pigtail that isolates the steam from the gauge.

0-4 lb vs 0-15 oz Vaporstat

The potential downside to a 0-4 lb vaporstat is that, like most controls, they tend to be more accurate in the middle of their range and less so at their low and high extremes. So if you install a 0-4 lb vstat and it turns out that your cutout pressure is, say, 8 oz, you're in the lower 12-1/2% of the operating range. On a 0-16 oz vstat, you're right in the 50% range.

I'd recommend that you first install the 0-3 PSI gauge and get an idea of what your operating pressures are, and use that data to decide which vaporstat to install.

Ptrol and Vstat

@ January 20, 2011 6:11 AM in Advice on vaporstat?

Hi David, that's my setup with the pressuretrol and vaporstat. The pressuretrol is the safety control and is wired into a 120VAC circuit, as orginally equipped by the manufacturer. The vaporstat is an an operating limit switch, wired in the NC position (break on hi pressure) set to cut out at 3.5 oz, and is in a low voltage 24 circuit along with a time delay relay.

My system runs at very low pressure, between 1 and 2 oz, and if it gets to the cut-out point on the vaporstat, I know that the system is completely filled with steam, so rather than short-cycle, the time delay relay kicks in and holds the thermostat circuit open for 20 minutes. The latent heat in the radiators continues to heat the building, and if the thermostat still isn't satisfied after 20 mins, the system will turn on again (though I've yet to have that happen).

I think the point of the "Why Do Honeywell Vaporstats Suck" thread isn't that they don't work, it's that they don't come calibrated out-of-the-box. For pros like Gerry Gill, this has got to be a huge pain to have to take time to set up each vaporstat, but as a homeowner I only had to do itonce, so no big deal. In that thread, Gerry describes a calibration jig he uses, and near the end of the thread is one I cooked up with a low pressure gauge and some 1/4" fittings.

Fuel economy

@ December 21, 2010 9:28 PM in Which LWCO? CG400 1060 or 2090

I check my boiler water level and quality regularly, and don't have any problems with foaming, so for me it came down to an issue of fuel (oil) economy. On a 45 minute heat cycle, the LWCO would shut the boiler down twice to do the foam check. Each time it did, the system took three minutes to heat back up to where it was before the shutdown. That's an extra six minutes of fuel burned recovering from the foam test in a single heat cycle. If that happens four times a day during the heavy heating season (say 12 weeks), that's 24 minutes * 12 weeks * 7 days = 2016 mins or 33.6 hours or roughly a week's worth of extra fuel used per season. That's why I opted to swap out the CycleGard for a SafeGard.

So back to your system. Let me say first that I'm not a pro, just a homeowner/enthusiast. From what you've described, my first concern is if your LWCO is working properly. Has the LWCO probe been cleaned/inspected recently, and has the LWCO been tested to ensure that it does in fact cut out on low water?

Is your normal water line at the recommended height when the boiler is not firing? According to the installation manual for your boiler, the water line should be 23-13/16 inches from the bottom of the boiler section leg, where it rests on the boiler room floor or boiler foundation.

Page 16 of the manual talks about installing an optional "reservoir pipe" if the time it takes the condensate to return to the boiler is longer than 10 minutes. This may or may not apply to your situation, but if it does it might explain why your water level drops (although it doesn't explain why the LWCO doesn't cut off).

When the boiler fires up how long does it take for the water to drop out of the sight glass? When it shuts down, how long does it take the water level return to normal?

Please post some pictures of your boiler so we can see what you're dealing with, including the LWCO, the sight glass, the near-boiler piping and the risers to the mains for starters.

Have you checked

@ December 21, 2010 5:46 AM in Programmable thermostat changes

the tstat reading with a datalogger placed in the same location?


@ December 20, 2010 5:53 AM in Which LWCO? CG400 1060 or 2090

[spurious double post deleted]


@ December 20, 2010 5:53 AM in Which LWCO? CG400 1060 or 2090

My boiler had the 2060 model when it was installed in 2009. You're right JP, this is the foam test feature. In the case of the 2060, it shuts the boiler down every 20 minutes for 60 seconds. So just when you've built up a good head of steam, BAM, shutdown, foam test. I ran a test with dataloggers last year and determined that the system takes 3 minutes or so to recover from the shutdown. By "recover", I mean that the temperatures at the measured locations reached their pre-shutdown values.

These units are fine if the HO isn't in the habit of regularly checking the boiler water. I wound up replacing mine with a SafeGard model that doesn't have the foam test feature.

And for the Library...

@ December 12, 2010 9:52 AM in steam heating enthusiasts christmas list.

... any of these books that you don't already have:

By Dan:

- A Pocketful of Steam Problems (With Solutions)
- E.D.R - Ratings for Every Darn Radiator
- Greening Steam
- Lost Art of Steam Heating
- Lost Art of Steam Heating Companion (CD)
- We Got Steam Heat!

Not specific to steam heating, but an entertaining read nonetheless:
- Working - Tales of life, love, mechanical mayhem…and getting even!

Books by others:
- Balancing Steam Systems Using a Vent Capacity Chart
- Lindhardt's Field Guide to Steam Heating


@ December 11, 2010 9:00 PM in Any Non-Professional Wallies Ever Go to Deadman's School?

I went to the one in Baltimore last month, and it was well worth the trip. I'd say go for it!


Just overnight

@ December 3, 2010 6:18 AM in let the data begin...

Just overnight. Still a pretty big difference though. Next time we're away for a couple of day's I'll see what the recovery time is.

With a six hour burn I'd expect you'd be cycling on pressure quite a bit. Any idea what the time span is between initial fire and first pressure cutout in a both setback and maintain situations?

Recovery from setback

@ December 2, 2010 9:42 PM in let the data begin...

That six hour burn time for recovery from a 12 degree setback seems awfully long. By way of comparison, my deepest recovery so far this season has been from 59 to 67 degrees, with an outdoor temp of 30 when the burner fired, and a recovery time of 1:20. I see you've downfired from the stock TR-30 specs (1.1 vs 0.85 gph). What's your steam MBH rating with the new firing rate?


@ November 18, 2010 6:02 AM in let the data begin...

This data is all from the Lascar data loggers, correct? What software are you using for your charting? There's an open-source (read: free) charting package that I'm using on my real-time data acquisition (and eventually control) project - LiveGraph.

One thing learned from all my data collection so far is that the system doesn't start to register pressure until steam is in the main. It takes about 2-1/2 minutes from the time the header is hot (>170 degF) until the main is too, and for that length of time, no pressure. Once in the main, the pressure jumps to 0.6 oz. Seems odd, because steam doesn't know header from main, it just knows Out, and Out hasn't changed.

Incidentally, congrats on achieving 2 oz operating pressure. Last season I ran around the house checking for leaking vents before I was convinced the system was really running that low.


@ November 16, 2010 6:52 AM in vents for 1-pipe TRVs

Hi JP, I've been studying the various outdoor reset control options (Heat-Timer, Tekmar, etc) and I think Mike is spot on when he says that the Heat-Timer model is better suited to commercial buildings. If you're looking for an outdoor reset control the Tekmar 279 may meet your needs. It provides for one or two indoor temperature inputs, and can handle even more using series-parallel wiring of the sensors (thermistors). Check out section F on page 8 in the manual, available at this link.
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