Heating Help

Cracked Radiator Vent

@ January 4, 2012 8:25 AM in Cracked Radiator Vent

I just thought I'd pass this along.  I still have a few Watts radiator vents I bought a few years back.  I replaced most of them because they were so loud and clanky when they closed, but I still had one in a downstairs bathroom.  Recently, i could hear a slight hiss from it, like it was failing to close.  I discovered an inch-long hairline crack along one side of it.  No, my boiler isn't running at excessive pressure.  I checked.  One more reason I won't buy Watts vents again.

Air Vent Noise

@ January 4, 2012 8:19 AM in Why does my radiator clang after releasing steam?

I think the OP is hearing the air vent opening and closing.  Depending on the brand, some of the alcohol-filled snap action ones can really make a loud clank when they actuate.  I still have cylindrical Watts branded vents on a couple of radiators. These are just like the imported ones available at the local big-box stores.  They sound like somebody shot them with a BB gun when they close.  The Hoffman #40 vents are a lot quieter, as are the slow-acting bi-metal units by Gorton or Maid-O-Mist.

Another

@ November 10, 2011 8:50 PM in Basic steam questions.

If you don't want to spring for a Gorton, you might want to tee in a second Hoffman 75.  I've been able to find them brand new on eBay for less than 50 bucks.

Significant?

@ November 9, 2011 2:26 PM in Combustion Gas Analysis

Time to steam? Hard to tell.  I guess it depends on how hot the boiler was to begin with.  I think I'm still hearing the main vents close about twelve minutes after the boiler comes on from dead cold.  The boiler comes on at 5:30 AM, the same time my alarm goes off . . . so I'll have to listen tomorrow morning.

Rep

@ November 9, 2011 2:23 PM in Combustion Gas Analysis

Burnham rep said to expect 450+ stack temperatures, 50 to 60% excess air, and about 10% oxygen in the flue gas.  Heating bills? Time will tell.  The efficiency values from the stack analyzer look better, but how the system reacts as a whole might be different.

Combustion Take Two

@ November 9, 2011 9:30 AM in Combustion Gas Analysis

My service-tech friend and I spent some time with the boiler last night.  He had contacted Burnham, and they told him that the boiler was designed to operate with high stack temperatures and plenty of excess air.  In residential situations, they wanted to make sure that there wouldn't be any condensation issues with old chimneys.

With the original orifices, the combustion and efficiency numbers were similar to the downfired situation, but like I said, the radiator vents were noisy.  There isn't much that can be adjusted on the burner.  He put the smaller ofifices back in, and checked the gas manifold pressure.  It was a little high, about 3.25".  He dialed it back to the factory spec. 3" and took some new readings.  The stack temperature went down to about 390 F, and the efficiency went up to 82%.  The radiator vents are almost silent again, and the system builds pressure nice and slowly, so it won't be cycling off the Pressuretrol except perhaps after a deep-long setback.   That's how we left it.  We'll see what happens to the gas bills.

I would go out and clock the meter, but it's 40 degrees out, very windy, and pouring rain here.   Ahhhh, November in Wisconsin!  At least it isn't snow . . . yet . . .

Will take more readings

@ November 8, 2011 10:44 AM in Combustion Gas Analysis

Thanks for the replies! 
I put the original orifices back in last night.  The boiler was cycling off of the 2 PSI Pressuretrol again, and the radiator vents were noisy enough to wake me up this morning.  With the smaller orifices, the boiler seldom builds more than a pound of pressure, and the vents are almost silent.

The boiler is an IN-6, with a 175,000 BTU input.  The gas meter clocked right at 175,000 BTU to begin with and about 158,000 BTU with the smaller orifices.
 
The combustion readings were measured with the probe inserted through the draft diverter, well into the chamber above the boiler flueways. (The draft hood is basically built right into the boiler.) That's about as close to an undiluted reading as I could come up with.

We moved into the house four years ago.  I replaced three missing radiators since then (risers were capped) and corrected a number of system issues, so even if I had ten years of gas bills, I don't think I could draw any conclusions from them.

My HVAC tech friend plans to come over after work tonight.  We will look at it together and take some readings with the original orifices for comparison.  I'll try to gather more information and will post again.

Combustion Gas Analysis

@ November 7, 2011 10:32 AM in Combustion Gas Analysis

I have a ten year old natural gas fired Burnham IN-6 steam boiler in my house. It is oversized and was short cycling and was hooked up to a marginal-sized chimney liner. After consulting Burnham, I down-fired it by 10% by replacing the orifices. I wanted to make sure everything was still safe, so I borrowed a Testo 330 from a service-tech friend.

Here are the results:
466 F T Stack
7.47% CO2
80.4% EFF
50.7% ExAir
7.6% Oxygen
1 PPM CO
2 PPM Undiluted CO
70 F Ambient

I just flushed the boiler very well with a pressure hose and an open 2" drain tapping, so I'm sure it's clean inside. The flueways look clean with an inspection mirror, but I didn't brush them. The boiler was running for about 15 minutes. It was steaming, but had not built any pressure. (The main vent closed right when I took the reading.)

The Stack temp seems a lot higher than the large commercial boilers at work. Is this normal?  Is the Excess Air too high?  Would I be better off with the stock orifices, even with short cycling?

Moved

@ November 7, 2011 9:30 AM in Help Me Understand My Combustion Gas Analysis

Moved

It's a serious affliction

@ November 3, 2011 9:56 PM in Speed of radiator venting

to have steam heat.  it took me three heating seasons before I was satisfied that everything was adjusted right.

Convector Vents

@ November 3, 2011 6:37 PM in Speed of radiator venting

As far as I know, the only difference is that convector vents are straight and radiator vents have 90 degree connections.  I think that convectors are very low-slung and their vent tappings are on the top instead of on the side.  If it is on a radiator, I assume it's mounted on an elbow?

Long Wrench

@ November 3, 2011 5:24 PM in help removing bushing from radiator

I've done a few.  I start by laying the radiator down and trying to unscrew the bushing with a pipe wrench and a long cheater pipe.  That worked for me . . . once.  On the others, I used a sawzall to make radial cuts outward through the bushing, stopping just short of the threads in the radiator.   With a couple of cuts most of the way through, the bushing might collapse a little when wrenched upon and unscrew nicely . . . or you might have to chisel it out in pieces. 

On my first try with the Sawzall, I actually damaged the radiator threads somewhat.  I had to bush it back down from 2" to 1.5" anyway, so I just used a little J-B Weld as pipe dope when I installed the new bushing.  If I thought I ever needed to remove that bushing again, I would have tried high-temp RTV silicone gasket sealer instead.  If the threads are OK, then regular tape or dope should work fine.

You know . . . fifty years from now, somebody will probably try to remove that bushing I glued in.  He may have some very unkind things to say about me.

Solid

@ November 3, 2011 5:14 PM in Speed of radiator venting

The Hoffman vents should be very good.  I prefer Gorton or Maid-O-Mist vents myself.  They operate slowly.  Any alcohol based vent like Hoffman, Dole or Watts is going to snap open and shut with an audible clink.  It bugs me some, but maybe I'm just neurotic.

Hot Water Vent

@ November 3, 2011 5:08 PM in Gorton valve spewing water in mom's old house

The Maid-O-Mist #67 vent is an air eliminator valve for a hot water system.  It won't work at all with steam.  If the guy who installed it doesn't understand the difference, you'd better find a qualified steam guy pronto.  Most plumbers don't understand steam heat at all.

Doors

@ November 3, 2011 4:56 PM in Speed of radiator venting

My room-to-room balance isn't perfect either, but it's a lot better than it was.   I just leave all the doors open most of the time and things seem to even out pretty well.

If the #5 is too big, you could solder the orifice shut and re-drill it smaller.  I did that on one I drilled out too big.  Or you could just buy a #4.  They're not horribly expensive compared to some other brands.

VariValves . . . no . . .

@ November 3, 2011 4:45 PM in Speed of radiator venting

Because of the way they are made, Varivalves seem to gurgle and spit a lot. Even when they are nominally closed, they still vent pretty fast. 

I like the Maid-O-Mist vents for experimenting. The vent orifices are removable. You can install #5s or even #4s everywhere, and if you want a particular vent to work faster, you can unscrew the orifice and drill it out a little bigger. Or, you can buy a variety of vents and swap around the orifices until you get the balance you need.

Adjustable vents are OK too, like the Vent-Rites, as long as nobody starts fiddling with them behind your back.  I also still have a couple of adjustable Watts radiator valves.  That's what I tried first.  They work fine, but they close with a loud clank and can really whistle when the system goes into vacuum at the end of a heat cycle.  They are still in a couple of rooms far from where I sleep, so they don't bother me much.

Number Five

@ November 3, 2011 4:34 PM in Speed of radiator venting

My big radiators near the stat have Maid-O-Mist #5s (.070" hole) if I recall correctly. (Gortons are numbered similarly.) A #4 vent is even slower, but I had fives in my collection.   Our upstairs bedroom could really use a bigger radiator, if one would fit.  It has about a size D (.1850") vent, and it is fully hot before the big radiators warm up much at all.  I tried super-fast VeriValve vents upstairs at first, but they vented so quickly that the radiators would gurgle and spit.

 

Why not?

@ November 3, 2011 4:17 PM in Speed of radiator venting

I have two big radiators nearest the thermostat.  I vent them more slowly than others. The house seems to heat more evenly that way.
 
I also think, within reasonable limits, it's perfectly acceptable to put faster vents on radiators in cold rooms, regardless of radiator size.  In my old house with forced air heat, I adjusted  the duct dampers to try to get the house to heat more evenly. We want our homes to be comfortable, right?  Why not try to get more steam to cold rooms? 

OK, in a perfect world, all radiators and heat registers/ducts would be properly sized for the rooms they are located in . . . but most of us are pretty well stuck with the radiators we already have . . . ideally sized or not.   

Yep

@ October 31, 2011 3:39 PM in Thermostat that controls boiler cycles?

You do have a point.  The shorter the time between heat calls, the shorter the time the boiler cools off, and the shorter the time it should take to make steam. 
The hotter the boiler, the faster it will lose heat though.  I'd wager that a lot of the cooling down takes place quickly after the burner stops, and that more frequent heat calls would lead to overall more dead time before steaming. . . . but then again as the boiler cools off, it does lose heat into the conditioned space, so not all of that heat is lost to begin with , , , oh my brain hurts!

Heating Calls Per Hour

@ October 31, 2011 3:04 PM in Thermostat that controls boiler cycles?

A steam boiler has about zero efficiency at the start of each heat call from the time that the burner turns on until the time the boiler actually starts steaming.  This might amount to ten minutes of each heating cycle.   (When the Pressuretrol is cycling the burner, the boiler is still steaming.)   If you can limit the number of times that the thermostat calls for heat, you can reduce the time that the burner is on and no steam is being produced. 

By limiting the number of heat calls per hour, or by adjusting the stat to allow a wider temperature swing to accomplish the same thing, you will reduce the number of times when the burner comes on, and reduce the overall time that the burner is on and NOT producing any steam.

VariValves Spit

@ October 31, 2011 2:47 PM in Valve spitting

Varivalves seem to spit more than any others.  There are three reasons for this. 

First, the vent will allow the radiator to fill with steam very quickly.  Having big open vents even on all of the radiators means that there is nothing holding the steam back anywhere, and often one radiator will get the lion's share of early steam, creating gobs of condensate that gets carried along with the rush of air coming out of that big open vent.

Second, the outlet of the Varivalve isn't much higher than the inlet.  It doesn't help the water in the vent drain back into the radiator very well, and doesn't present much of of a barrier for that water to get blown out the next time the system comes on.

Third, Varivalves don't have any kind of float in them. Unlike most vents, if they get flooded with condensate, they will still open up and spit it out.

I had three of them on various radiators and gave up on them, switching to Gorton or Maid-o-Mist vents.   After one season with containers under them to catch their drippings, I sold them on eBay for a fraction of what I paid for them.  If you don't want to waste your investment in VariValves, you might first try  closing them all up about 75% shut.  Then if you find a radiator that's slow to heat up, you can open that vent uo to half.  It doesn't totally overcome the inherent design problems, but it should help.

Maid-O-Mist vents are my favorite.  They are like Gortons, with a bimetal actuator, but they have removable orifices that can be removed and enlarged if necessary.  They are quiet and fairly inexpensive too.  Some say that they are not as durable as Gortons, but I haven't had issues with either, and I own both.

Depends

@ October 31, 2011 2:25 PM in Pressure setting and fuel/gas consumption

5 PSI steam is about 15 degrees hotter than 0 PSI steam.  That basically means that the flue gasses going up your chimney will be about 15 degrees warmer too.  That 15 degrees is heat that could have gone into making more lower pressure steam instead of floating away.

However, even though my Pressuretrol is set at it's lowest reliable setting, 2 PSI, the boiler almost never reaches that pressure before the thermostat is satisfied.  Most of my heating is done at close to zero pressure.  If I set the Vaporstat higher than 2, it probably wouldn't change my gas bill much at all . . . because the boiler would very rarely run long enough to make any appreciable pressure anyway.

The same thing holds true for me installing a low-pressure Vaporstat.  My boiler spends so little time above 1/2 PSI that the amount of heat wasted by the few minutes a day that the boiler might operate at a little higher pressure would not mean much. That's for residential.  If I had a multi-unit apartment building where the boiler was steaming most of the time, then lower pressure would probably be worth it.