The time of year I hate most. Getting ready to shut it down. :(

PMJ

ChrisJ said:

PMJ said:

ChrisJ said:

You cannot include energy for the fan in the AFUE rating because it's nearly 100% efficient. AFUE isn't a cost rating, it's an efficiency rating.

You're right - I understand that is what AFUE is . I just find it annoying because with a boiler it basically is the net efficiency of the heating system. With forced air it is not.

I agree,
But how do you do that? How can you equally compare the total cost to run various heating systems?

Measure the electric comsumption of the whole unit. You have to measure the full load amps when it is running at the main and calculate the KWhours. If you want to be totally fair do the same for a boiler.

ChrisJ

PMJ said:

ChrisJ said:

PMJ said:

ChrisJ said:

You cannot include energy for the fan in the AFUE rating because it's nearly 100% efficient. AFUE isn't a cost rating, it's an efficiency rating.

You're right - I understand that is what AFUE is . I just find it annoying because with a boiler it basically is the net efficiency of the heating system. With forced air it is not.

I agree,
But how do you do that? How can you equally compare the total cost to run various heating systems?

Measure the electric comsumption of the whole unit. You have to measure the full load amps when it is running at the main and calculate the KWhours. If you want to be totally fair do the same for a boiler.

For my boiler, I could be generous and say 0.150kwh for one day on the coldest day of the year. Look mom! No pumps!

PMJ

ChrisJ said:

For my boiler, I could be generous and say 0.150kwh for one day on the coldest day of the year. Look mom! No pumps!

Exactly! It is a significant advantage steam has from a maintenance side too that it never gets proper credit for.

ChrisJ

Hatterasguy said:

PMJ said:

Measure the electric comsumption of the whole unit. You have to measure the full load amps when it is running at the main and calculate the KWhours. If you want to be totally fair do the same for a boiler.

I'll bet that if I measured the draw on the Beckett with the blower and the pump running, I'd be shocked at the cost to run it.

1150 hours per year.

$.225/KWH

That's an interesting idea.

Even if a wet based boiler is more efficient, does the cost of running the burner use more than the boiler saves?

I think we all need to chip in and buy a huge development together so we can install 10-20 steam systems in identical houses and experiment.

All we need is money...

ChrisJ

Hatterasguy said:

ChrisJ said:

That's an interesting idea.

.

Now you've piqued my curiosity. Due to the design of the system, I can easily get an ammeter in series with the burner.

I'm going to do it this weekend and get a measurement on current. Then I'll know how much money goes down the tubes in that pump motor.

What about reading the name plate on the motor?

ChrisJ

Hatterasguy said:

The specs for it read: Operating load: 5.8 A, Max.

Hard to quantify that.

So call it 3-4A, but whats the power factor?

BobC

The nameplate current draw is only valid if the motor is running at it's rated load. Measuring the current under running conditions will be more accurate. Even then your calculation of running watts will only be an approximation because the motor is inductive not resistive, the voltage and current are not in phase.

Bob

ChrisJ

BobC said:

The nameplate current draw is only valid if the motor is running at it's rated load. Measuring the current under running conditions will be more accurate. Even then your calculation of running watts will only be an approximation because the motor is inductive not resistive, the voltage and current are not in phase.

Bob

True,
But we have to assume they didn't put a motor that is 3 times the size required for the load. You can also figured out a rough power factor by the design of the motor.

Larry_52

ChrisJ said:

Hatterasguy said:

So, what's the plan for the summer? Fill it completely to the header? There is some support for that from some dead men.

No,
I leave it about where it is now, slightly overfilled which is how I run it all year.

The problem is to fill it to the header you want a good oxygen scavenger to pull the disolved oxygen out of the water because you can't boil it. Rhomar's Boilerpro 903 can do this but I don't think Steamaster is good enough. I recall something in Steamaster kind of works as a scavenger, but barely.

This is also why Rhomar tells you to fill it to the header, because you're using their product. I'd never even consider doing it with raw water.

You might already be aware but sodium sulfite is what you want to add to scavenge oxygen. It is real cheap, and you are correct steammaster uses sodium nitrite which is an oxidizer promoting magnetite oxide layer which in turn protects the metal from free oxygen. The sulfite actually scavenges the O2 but it's reaction time is temperature driven, higher the better.

ChrisJ

Larry said:

ChrisJ said:

Hatterasguy said:

So, what's the plan for the summer? Fill it completely to the header? There is some support for that from some dead men.

No,
I leave it about where it is now, slightly overfilled which is how I run it all year.

The problem is to fill it to the header you want a good oxygen scavenger to pull the disolved oxygen out of the water because you can't boil it. Rhomar's Boilerpro 903 can do this but I don't think Steamaster is good enough. I recall something in Steamaster kind of works as a scavenger, but barely.

This is also why Rhomar tells you to fill it to the header, because you're using their product. I'd never even consider doing it with raw water.

You might already be aware but sodium sulfite is what you want to add to scavenge oxygen. It is real cheap, and you are correct steammaster uses sodium nitrite which is an oxidizer promoting magnetite oxide layer which in turn protects the metal from free oxygen. The sulfite actually scavenges the O2 but it's reaction time is temperature driven, higher the better.

Hi @Larry
Can sodium sulfite be added in addition to the sodium nitrite?

PMJ

ChrisJ said:

BobC said:

The nameplate current draw is only valid if the motor is running at it's rated load. Measuring the current under running conditions will be more accurate. Even then your calculation of running watts will only be an approximation because the motor is inductive not resistive, the voltage and current are not in phase.

Bob

True,
But we have to assume they didn't put a motor that is 3 times the size required for the load. You can also figured out a rough power factor by the design of the motor.

This is why you just use a clamp on ammeter at the main supply and see what the current in amps actually is when the unit is running everything. Multiply that by the voltage to get watts.

ChrisJ

PMJ said:

ChrisJ said:

BobC said:

The nameplate current draw is only valid if the motor is running at it's rated load. Measuring the current under running conditions will be more accurate. Even then your calculation of running watts will only be an approximation because the motor is inductive not resistive, the voltage and current are not in phase.

Bob

True,
But we have to assume they didn't put a motor that is 3 times the size required for the load. You can also figured out a rough power factor by the design of the motor.

This is why you just use a clamp on ammeter at the main supply and see what the current in amps actually is when the unit is running everything. Multiply that by the voltage to get watts.

No,
This would give you volt amps which is not watts.

I use an actual watt meter when working on my antique refrigerators because I'm usually measuring 120-180 watts with a really bad power factor. For example 2.5A @ 117V with a power factor of .50 = 146 watts, not 292 and that's often what I see with my refrigerators. Their power factor blows under light load which is typical of any resistive start split phase motor.

If @Hatterasguy wants to be exact, he'll need a watt meter otherwise a rough estimate is close enough for what he's doing. Unless you know the exact power factor knowing the exact current consumption is moot.

That's my opinion anyway.

ChrisJ

Hatterasguy said:

ChrisJ said:

No,
This would give you volt amps which is not watts.

I use an actual watt meter when working on my antique refrigerators because I'm usually measuring 120-180 watts with a really bad power factor. For example 2.5A @ 117V with a power factor of .50 = 146 watts, not 292 and that's often what I see with my refrigerators. Their power factor blows under light load which is typical of any resistive start split phase motor.

If @Hatterasguy wants to be exact, he'll need a watt meter otherwise a rough estimate is close enough for what he's doing. Unless you know the exact power factor knowing the exact current consumption is moot.

That's my opinion anyway.

What is intriguing to me is the fact that an ampere measurement will result in a value that is significantly less than the actual power consumed (due to the power factor).

The question is how the electric meter can measure the power consumed if it cannot use amperes as the unit of measurement.

No, you're backwards I think,
An ammeter + volt meter will give a higher reading than you really have.

The electric company doesn't use an ammeter, they use a watt meter.

http://en.wikipedia.org/wiki/Wattmeter

Some places, get charged for volt-amps instead of watts if they have a lot of inductive loads, such as a bakery for example. Because if you're drawing a ton of current due to a bad power factor it does cause huge headaches for them. By ton of current I mean hundreds or even thousands of amps, not 5.

BobC

Fifty some odd years ago Wentworth had some equipment that drew so much current they had to notify Boston Edison they were going to turn it on. If they didn't the area would go down because the load was so huge and the institute would catch hell for causing the collapse.

Bob

ChrisJ

Hatterasguy said:

ChrisJ said:

No, you're backwards I think,
An ammeter + volt meter will give a higher reading than you really have.

The electric company doesn't use an ammeter, they use a watt meter.

http://en.wikipedia.org/wiki/Wattmeter

Some places, get charged for volt-amps instead of watts if they have a lot of inductive loads, such as a bakery for example. Because if you're drawing a ton of current due to a bad power factor it does cause huge headaches for them. By ton of current I mean hundreds or even thousands of amps, not 5.

OK, thanks for that.

The electric meter, being a wattmeter, would measure something less than what I'm going to get by doing a VA calculation.

So, I'd need to make an estimate of the power factor to determine that actual power consumed by the motor (less than VA).

Can you tell if the motor is a capacitor run type? That can greatly increase the power factor. If there's a capacitor it may be just for starting though. If there is no capacitor at all, then it gets a lot easier.

Typically a normal split phase motor will have a power factor of .50 - .60.

KC_Jones

When I worked for the power company years ago they showed us an apparatus that could stop a meter, but still allow all the equipment to run, lights to light etc. It wasn't simple, but it worked. The inductive loads can really screw with those meters. Another reason the meters are changing now. Essentially with a motor and an old meter you use more electric than they were billing you for. If you look at the sine waves for the current and voltage the more "out of time" those waves get the "less" electric the meter shows. Those waves need to be in alignment to have a true measurement. This only applies with the simple mechanisms in an old meter. Like I said can't remember all the specifics, but supposedly newer "smart" meters are better. The electric company is always working to figure out how to get our money.

ChrisJ

KC_Jones said:

When I worked for the power company years ago they showed us an apparatus that could stop a meter, but still allow all the equipment to run, lights to light etc. It wasn't simple, but it worked. The inductive loads can really screw with those meters. Another reason the meters are changing now. Essentially with a motor and an old meter you use more electric than they were billing you for. If you look at the sine waves for the current and voltage the more "out of time" those waves get the "less" electric the meter shows. Those waves need to be in alignment to have a true measurement. This only applies with the simple mechanisms in an old meter. Like I said can't remember all the specifics, but supposedly newer "smart" meters are better. The electric company is always working to figure out how to get our money.

My understanding is even if the current and voltage are completely out of phase a kWh meter will still measure the correct amount of power?

KC_Jones

It can be measured correctly, but for economic reason (in the past) they didn't make the meters that sophisticated. Also in the past when a lot of those meters were designed there weren't many electric motors in use, it was mainly lighting which is a pure resistance load (for the sake of argument). It's been years since I studied it so I can't remember all the details, but watching an electric meter not move and motors and lights working just fine...that tends to stick with you.

PMJ

Chris is correct that VA are not always the same as watts. For most of the consumption in a house they are the same. If the load is a heat coil they are. If it is a motor, they are not. VA's is larger than actual watts billed for on devices where they are not the same.

Apparent power (what we would get with my clamp on meter approach) is VA. Real power (watts) is what the motor actually consumes, what the meter on the house measures, and what we pay for. But the power company must supply the apparent power (VA) amount for the motor to actually run. The distribution system (wiring) must be sized at the apparent (VA) amount. So in residential in most places it is the power company who loses since old motors with low power factors in homes require the power company to supply VA but it only bills the customer for real power watts. They don't pursue it because motors are a small percentage of the total in residential and PF's in all things are steadily being improved.

For our discussion here I don't think the difference between the two means much which is why I suggested this approach. I was just suggesting a simple way to get a quick idea what % of the total cost the electric was to operate a forced air furnace or a boiler. My clamp meter way will give you an amps number which converted to KWHR will be somewhat higher than what you actually have to pay for. Anyone who thinks more accuracy is required can invest in what is required to measure the actual watts the thing is using(like the utility meter does) or look up the power factor for the motor inside and adjust the result accordingly. I'm saying It doesn't take all that just to get an idea about how big a piece of the pie in forced air heat the electricity is. I was just ballparking the thing here - not trying to drill it down to pennies.

ChrisJ

@PMJ,

My assumption was the motor being used would have a very bad PF. I guess this isn't the case so I agree, an ammeter is probably fine.

Like I said, on my refrigerators the PF is only .50 or .60 so the difference between va and watts is huge. 292.5va vs 146.25 watts. Some guys have told me that wiring a capacitor in line with the start winding can greatly improve this but I've been too nervous to experiment. The last thing I need is to burn out the start winding on an 80 year old motor that I can't afford to have rewound.

RobG

Guys, start a new thread please. This was supposed to be about shutting down a steam boiler for the summer.

PMJ

RobG said:

Guys, start a new thread please. This was supposed to be about shutting down a steam boiler for the summer.

Seems Ok to me to respond to comments and questions on a thread from the original poster whatever they may be about.

ChrisJ

@RobG is right,

I'm sorry, we should start a new thread.

Larry_52

Chris, I really don't know if there would be a major issue with the nitrite and sulfite or their products of sulfate or nitrate. I have someone at work who might be able to give some insight to that. I only see that they would equate to higher TDS. There wouldn't be an issue at room temp. If the sulfite was with a catalyst then the nitrite might affect the catalyst.

I think for the the offline season a properly cycled boiler in nitrite corrosion inhibitor would be fine. If you were to add sulfite you would want get the test for residual to monitor for approx 50ppm residual. That seems overkill based on the effort and payback.

In sulfite raising water into header risers would lower the surface area exposure to O2