"William Deans" wrote in message
news:1106862352.4ff6c6d73e74beec21000ad94720fcba@t eranews...
Sorry, at $2500 the boiler never pays for itself -- at $3500 you LOSE
$100/year

William


"William Deans" wrote in message
news:1106862012.a9aa9a0b82b663a5f1b1dd01c12c4310@t eranews...
Greetings,

a) you probably just need to install an expansion tank
b) expansion tanks cost around $25-- you can install it yourself if you
can
screw together pipes
c) if adding an expansion tank doesn't work -- and it probably will --
then
try replacing the overflow valve
d) you probably DO NOT need a new boiler -- to figure out how many years
it
would take the new boiler to pay for itself based on increased efficiency
perform the following calculation

(cost of new boiler)/(((efficiency of the new boiler)-(efficiency of the
current boiler))*(yearly heating bill)-((cost of new boiler)*(discount
rate)))

Example Calculation:
$3500 cost of new boiler
0.85 efficiency of the new boiler
0.60 efficiency of the current boiler
$1000 yearly heating bill
0.10 discount rate == what return would you get on the money invested
elsewhere?

3500/(0.85-0.6)*1000-2500*0.10
3500/0 == the boiler would never pay for itself --EVER

Hope this helps,
William

"johnnyok" wrote in message
...
Well, the problem isn't 75 years old but the boiler is. I have a
Weil-McLain oil boiler converted to gas....size 5-w-19 series D...

Efficiency expert said the boiler was handling the house fine so didn't
consider replacing it. One of the pipes started leaking and the Gas
company
replaced the pipe and put in an over flow valve (none was there). The
valve
drips all the time.....(a bucket a day). People talk about an
expansion
tank (there is NONE). Others suggest that the overflow valve should
not
have been installed. The boiler is running fine but sure is a pain to
empty
the bucket everyday... Any thoughts, comments or possible solutions
appreciated. John

Hi William,

I'm glad you did the above calculations.

Too many of the "pros" on here always advocate replacing a furnace or boiler
saying that the fuel savings will
pay for the new unit.

In many cases, as you pointed out - that simply isn't true.

The payback time can be so long that you are better off with the money left
in the bank.
In other cases, by the time the new unit is paid off with fuel savings, it's
time to replace that unit.

It's been my experience that the only time to replace an old unit is when it
can't be made reliable or reasonably safe.
I've only had that occur under two situations: a cracked heat exchanger with
a furnace, or a cracked casting in a boiler.

I've got a neighbor, an elderly women who takes pride in the fact that her
1948 vintage, non electric gravity gas furnace (an "octopus") still works
fine. With the replacement ductwork required, I'd expect a new installation
to run her at least $5000.
Even at her present efficiency of around 50%, she'd only save around
$300/year. That's a payback of over 16 years.
She wouldn't see it in her lifetime and it wouldn't be worth it in any case
unless gas rates go up over 150% in that period.
Such a hike in gas rates has never happened in history within that period of
time. In the meantime, she is the only one in the neighborhood who has a
furnace working during a power failure due to its millivolt thermostat/main
gas valve system.

Doug