how do I test the pressuretrol cut-out

Tim Gardner

I have read the one-pipe steam sections of Dan Holihan's "The Lost Art of Steam Heating", so I understand that the system is supposed to cycle on and off.

Mine just stays on until the temperature gets up to the thermostat setting, at least it did when I tested it today, taking the house from 65 to 75. The pressure gauge showed zero the whole time. The honeywell PA404A is set for cut-in at the lowest setting, 0.5, and I believe the differential is set to the lowest setting as well, about 1.5 if I am reading it correctly.

I took off a radiator vent and could feel the dry steam coming out, but I don't know what 1.5 psi feels like so I don't know if it was more or less than this.

Perhaps I have a leak in the system? Perhaps the pressuretrol and the gauge are both broken? Does it take more than an hour to work up more than 1.5 psi?

I'm not sure what to check next.

Any ideas would be appreciated. Thanks, Tim

Richard D._2

With steam

you should get a pro,alot can go wrong and the end results are not good..You may have a plugged pigtail,and a 1 1/2 to make steam is not gignt..Call your tech to check it out!Cheaper than a hospital bill!!!
Good Luck Richard

Tim Gardner

Well, the "pros" serviced my system last month, and filled it with "steam clean" from IPC, giving it a green color.

I pay them to service it every year. If I need to pay more, I will. But I don't want to pay more than necessary.

But I want to understand it, since I am considering adding a couple of risers.

Thanks,
Tim

Tim Gardner

Well, the pros serviced my system last month, and filled it with "steam clean" from IPC, giving it a green color. According to them, it is fine.

I pay them to service it every year. If I need to pay more, I will. But I don't want to pay more than necessary.

But I want to understand the system, since I am considering adding a couple of risers.

Thanks,
Tim

Unknown

Look at it differently.

Turn your stat way up again. Go down to the boiler and see if the header above the boiler gets hot in a minute or so. from that time, it should heat to the main vent within a minute or a little more.

After that, all of the radiation should begin to heat together. Not all the way across, yet, but all of them together. Pressure really has nothing to do with it yet, because all of the vents are still open on the radiation.

When all of the rads are hot all of the way across, the vents will shut and all of the heat that you can deliver is being produced. The pressure is still zero. A perfectly sized system will not climb fast, BUT....

Once the system IS hot, the boiler no longer has to deal with cold pipes. The energy planned for warming the pipes is no longer needed. The pressure can begin to climb. NOW you need a pressuretrol to shut it off, while the thermostat is cranked to a rediculous number.

Normally, it wouldn't run this way.

Now that I've said all this, I think you might be undersized. The timing will bear it out. Have you measured your load yet? Are your pipes insulated? Is the boiler piped exactly right? Can you hear the vents operating?

Let us know...

Noel

Big Ed

Pressure

Raise the thermostat to it's highest setting and run it until the burner shut off .In this mild weather the house would get pretty warm so you might want to open a few window. You can miss a steam leak , all you have to do is listen for one. ..

A hour and for reaching limit it if far too long . Why did they add the green stuff ? Is your boiler small-new or big-old ? oil gas ?

Tim Gardner

To answer your questions first: they added the green stuff because the glass tube was getting clogged up. Should they have cleaned it instead? At first he told me he was going to clean it but then he changed his mind and added the green stuff.

The boiler is a delco, so it must be 40 or more years old. The burner is oil, 1.25 g/hr I believe.

I did set the thermostat up to 85 and ran the furnace from 68 up to 75 for over an hour with windows open and it never shut off and always read 0 pressure. I walked around and listened for a steam leak but did not find any. The house was not quiet at the time, though, so it is possible I missed something.

Thanks,
Tim

Unknown

Time to measure the radiators.

No guessing will tell you if the boiler is big enough.

Noel

Tim Gardner

specs and test results

HOUSE: 1925 tudor, stucco uninsulated, 25' x 35', two floors and an unheated attic.

BOILER: Delco-Heat boiler Model DB4S. I understand Delco stopped making them in the early sixties, so it is probably 40 years old or more.

BURNER: Carlin 100 CRD oil burner which has a label saying it is between 0.5 and 2.25 gph. The oil company once scrawled 1.25 on one of their tags, but I'm not sure when.

COIL: Large coil in boiler supplies DHW. Probably somewhat clogged or scaled because output is not nearly what it was 10 years ago. Asked a plumber to replace it three years ago but never saw him again in spite of calls every year in which he repeats to me that the coil was ordered but that there was some problem that he was going to look into.

SERVICING: Serviced annually by contract by the company which supplies my heating oil. At last servicing the glass tube was getting clogged, so service man added "Steam Clean" by I.P.C., so now it is green.

RADIATION: House has eleven one-pipe radiators with total EDR of 236 with a mix of Dole, Hoffman, and Gorton vents. Some risers are one and one quarter inches and some one inch. The longest riser is about ten feet. It looks like one of the radiators was moved or added about 40 years ago and they used galvanized pipe which is looking flakey, but the rest of the pipe looks good as far as I can tell.

HEADER: A three inch header goes up 28 inches above the water line to a tee from which a 2 inch main goes right. The tee goes up to an elbow for another 2 inch main going left. There is and NO equalizer.

MAIN, MAIN VENTS, RETURN: The right main goes 40 feed around the basement to a gorton #1 and then drops into a wet return, and the left goes 30 feet around to a gorton C where it too drops into a wet return. Both vents are straight up on the drops, not set back like the book "The Lost Art of Steam Heating" says they should be. The wet returns go into the concrete and a single one emerges several feet away and runs around the floor of the basement back to the boiler. There is NO Hartford loop.

INSULATION: The header and main is insulated all the way around the basement except for a 3 foot section.

TEST RUN: The header started out warm, perhaps because the DHW keeps the burner on periodically. I cranked up the thermostat, and the burner came right on, as usual. Within 15 minutes, the mains were hot to 10 feet, by 20 minutes they were hot at 20 feet, and within 25 minutes the main vents at the end of the mains were hot. I couldn't hear air coming out of the main vents or the radiator vents, but perhaps I don't know how to listen well enough. After 40 minutes all the radiators were hot all the way to the vents except one which is just warm (probably needs a different vent). The water in the boiler was "breathing" irregularly up and down in the glass tube about one half inch up and down every two seconds on average. After 95 minutes the burner had still not shut off and the pressure gauge still reads 0. I unscrewed one of the radiator vents and somewhat wet steam shot out with about the force of a tea kettle. I had to take the kids to school, so I set the thermostat back down and the burner went right off.

Any insight would be appreciated. Should I try it again for longer? Should I call back the guys who serviced it?

Thanks,
Tim

Unknown

Maybe.

I think the burner might be fired at under 1.00 GPH, from your description of your system, maybe way under.

If not, I suspect lots of extra air on the burner, or about a quarter inch of soot on the inside of the boiler.

The firing rate that you mentioned (1.25) should be plenty big enough to do the job, but the steam just isn't getting out.

Good on the vents. If there are enough and they work, they should be silent.

The timing of the steam is horrible, though.

Noel

Dale

Stack temp

I think your stack temp is probably too high, that is as I think Noel mentioned that the heat is going up the chimney not into the water, I would try to get a service person who has and uses modern digital combustion testers. You could buy a stack temp thermometer and check it yourself, one would hope there's already a test hole in the flue pipe, if there isn't the first recommendation should certainly be followed. Even an old oil boiler is set up correctly should give you a net ( read minus basement temp) of about 450 degrees. If it's 600 degrees the insulating value of soot is demonstrated. If you don't mind some wrench work unscrew the main vent and start the boiler, the steam should come really fast. I'm thinking you might also have main vent problems but the stack temp check and the modern tuneup would be my first choice.

Tim Gardner

Thanks! Sounds like several great suggestions.

But I'm afraid I don't quite understand. Are you saying the temperature should be about 450? And that 600 would be too hot? Does soot prevent steam?

I will try the main vent idea too.

Thanks again,
Tim

Unknown

yes on the soot

The stack temperature represents the heat that the boiler didn't catch.

The fire temperature minus the stack temperature gives you how much the boiler grabbed. Higher temp in the stack means less heat went into steam.

Extra air cools the fire itself, and increases the volume of flue gas going through a fixed sized opening. That means it goes faster. Faster means less time in the boiler, so less heat is scrubbed. It hurts you on both ends.

I think 1/8" of soot reduces the heat transfer by 9%; anybody remember the actual numbers?

Noel

Steamhead

It's either under-vented or under-fired

Those mains should fill with steam in about a minute. I'd vent those mains with two Gorton #1 vents on each. I'll bet the existing vents are shot. But if the mains don't heat quickly with the vents removed as Dale suggested, the boiler may be under-fired.

OR- the boiler may be leaking steam into the chimney. In that case, you'll probably see white smoke coming out the top of the chimney when the burner is running. Try adding enough water to fill the boiler up to the top (DO NOT DO THIS WHILE BOILER IS HOT), where the steam pipe connection is. If water spills onto the floor or into the firebox, the boiler is leaking and needs to be replaced.

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