Plan for Big Old Inefficient Boiler

Kevin O. Pulver

Matt, even if you are gone from Tenn. in 10years, the boiler would be a good investment. It would make the house worth a bunch more when you sell it, and in addition you could brag to potential buyers how little it costs to heat the place. Not to mention the fact how much it would have saved you by then. I second the motion for the Knight by Lochinvar. They are a great boiler. Super efficient and compact. They also look COOL! Anyone who is looking at your dinosaur boiler 10 years from now (and it's ancient NOW)will ask you how much it costs to heat the place, and then they'll either: 1- mentally deduct the price of a new boiler from your asking price. or 2- they'll have less imagination and just drop your home from consideration.
The Knight has other advantages for you in that it's sealed-combustion and fully condensing and modulating. It's 92% AFUE and I would guess yours is maybe a bit out of tune and dirty besides technologically outdated. Maybe it's running at 60%? Look into it. Kevin

MattK

Plan for Big Old Inefficient Boiler

I have a big old Janitrol Boiler from the 50's give or take. It is rated at 270,000 BTUs for a large brick house (3,500 sq. feet) in Tennessee where winter temps fluctuate around 30 degrees. The system is an open system gravity circulating (no pump) hot water system with old style standing radiators.

Setting the thermostat at about 62 I ended up with a nearly $600 gas bill for december. If it snows here, I'll be selling a kidney. I must do something, even if it means a whole bunch of electric space heaters.

The big boiler basically will kick on full blast for about 30 minutes every 3 or 4 hours. Surely this can't be efficient. I've seen a little bit about boiler modulation, is this something that can be retrofitted to an old boiler like this? Am i best off investing in a new system, lower btu rating perhaps?

Thanks a bunch,
Matt

kevin coppinger_4

the first thing....

is to insulate, caulk and seal up the house....clean the boiler up and then look into the new boiler...although it is very old to start.kpc

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Long Beach Ed

Some suggestions...

Gravity hot water can be a beast when used with an oil or gas fire that cycles on and off. Remember these systems were designed for coal, where the boiler would remain hot for hours if not days.

There are a few things to look at:

Is the boiler sized properly? A heat loss calculation on the building will tell you that.

The system can be converted to a pumped system, but the job is not as simple as adding a circulator. With such an enormous amount of water in the system, the thing would run all day (as it probebly does now) to raise the water temperature a few degrees.

We would convert it to what's called a primary/secondary injection system, where circulators power two interlaced water loops; one for the house radiators (which you have now) and one for the boiler. In this way, hot water from the boiler is injected into the main loop usually using a variable speed pump and a computerized control. This would save you a fortune and would have to be done even if you replaced that old boiler.

This is all quite an investment, but by doing this you can possible zone the house and see even more savings. Your investment will probably be returned in 5 - 10 years.

In the meantime, make sure the burners are properly adjusted to maximize efficiency and that the boiler is clean.

Long Beach Ed

Dave_12

Plan

Modulation is not something that can be easily or safely retrofitted to an old residential boiler. I would agree that spending money on insulation and sealing the building envelope is the first thing to do. The next would be to have a boiler properly sized to the heating load. Lochinvar is based in TN, so their Knight boiler would be a good choice. If that gives you sticker shock, their Solution boiler is a nice 84% two stage unit.

MattK

"In the meantime, make sure the burners are properly adjusted to maximize efficiency and that the boiler is clean."

Any information on how to adjust burners. I had the system looked at last winter. Basically they just took each burner off, shook out the junk and put them back in place.

I don't see myself in the Tenn area in 10 years, since my work will probably require me to relocate within that time frame.

Thanks for the information,
Matt

soot_seeker_2

A combustion analysis must be done using the proper equipment.

As one highly regarded guy around here once said, "the laws of physics came before the laws of economy." Without investing money into this beast, you're going to be paying high fuel costs.

Insulate, close up unused rooms, shut off unused radiators. It's pay me now or pay me forever...

Long Beach Ed