Condensate tank replacement

Sqdqo

A friend has a leaking condensate tank on a large residential system. This tank is part of a two tank system, each with their own pump. The system is not an automatic  alternating system, its a manual alternation.The leaker is a Sterling steel tank appr 25 gallons. The 2nd tank is appr 15 gals.  The contractor is suggesting a single 25 gallon s.s. tank unit with duplex alternating pumps.
There are two Weil McLain LGB6 boilers in this system. The quoted price for the new tank system less any labor is nearly $XXXX. Does this sound reasonable? Is an alternating system the right option or is manual adequate?

Jamie Hall

Err.... um. If you have two boilers off the same tank, each should have its own pump controlled by the water level in the boiler only. Boiler makeup water, if any, goes to the tank controlled by a float in the tank.

JUGHNE

Are the two boilers tied together to a common header or are they two separate systems completely?

pecmsg

Sqdqo said:

A friend has a leaking condensate tank on a large residential system. This tank is part of a two tank system, each with their own pump. The system is not an automatic  alternating system, its a manual alternation.The leaker is a Sterling steel tank appr 25 gallons. The 2nd tank is appr 15 gals.  The contractor is suggesting a single 25 gallon s.s. tank unit with duplex alternating pumps.
There are two Weil McLain LGB6 boilers in this system. The quoted price for the new tank system less any labor is nearly $*,***k. Does this sound reasonable? Is an alternating system the right option or is manual adequate?

Pricings not allowed.

Pumpguy

In my experience, your scenario of a leaking welded carbon steel condensate pump receiver tank is quite common. I would guess a typical life of these steel tanks is 10 years. Typical wall thickness is only 3/16".

Welded stainless steel tanks are available, but are quite thin wall too, and you need to be careful about the condensate chemistry. Some manufacturers recommend against using stainless steel tanks if any chemical ending in "ide" is present.

Best choice is tried and true cast iron tank. I see cast iron tanks that are now 100 years old and still perfectly sound. More than one manufacturer offers a 20 year warranty against corrosion failure on their cast iron tanks.

Sqdqo

JUGHNE said:

Are the two boilers tied together to a common header or are they two separate systems completely?

Sqdqo

Im not a heating system expert so these descriptions are to the best of my ability.   

The two boilers are part of a common system. Each has a low fire / high fire option and can be brought online as needed depending on outside conditions. 

The boilers are fed from on site well water that I'm sure has never been tested for any "ides". There are no chemicals added to the feed water. The tank that has started to leak has been there for at least 20 years.

As far as a concern for my discussing any pricing I was being general in the noted cost I posted trying to determine if the material cost sounded reasonable. Sensoring that is pretty peddy.

Jamie Hall

"Sensoring that is pretty peddy." Learn to spell. Some rules seem so, but it is the rule. Depending on where you live, labour costs can vary over a very wide range, and it isn't fair (or legal) to quote labor costs -- and they are often the largest item in any sort of work.

Now to the tank. 20 years is a very reasonable life for a steel condensate tank. As noted, cast iron will last forever. Steel, not so much.

I doubt that well water is going to be a problem, although there are some areas where it can be high in chlorides and it wouldn't hurt to check. What can be a problem, though, is if you are using a fair amount of it, as the dissolved oxygen in the fresh water will cause corrosion.

I would still prefer to see this system set up as a boiler feed system, with separate pumps for each boiler controlled by the boiler water level -- not the condensate tank level. I presume this is steam, so I also presume that there are the usual overflow/spill traps for the two boilers feeding the tank, in addition to the returns. Both pumps can and probably should operate from a single receiver tank, if the system is common. If the returns are split, but not the supplies, then you could have two tanks -- but they need to be interconnected.

Sqdqo

Jamie Hall said:

"Sensoring that is pretty peddy." Learn to spell. Some rules seem so, but it is the rule. Depending on where you live, labour costs can vary over a very wide range, and it isn't fair (or legal) to quote labor costs -- and they are often the largest item in any sort of work. Now to the tank. 20 years is a very reasonable life for a steel condensate tank. As noted, cast iron will last forever. Steel, not so much. I doubt that well water is going to be a problem, although there are some areas where it can be high in chlorides and it wouldn't hurt to check. What can be a problem, though, is if you are using a fair amount of it, as the dissolved oxygen in the fresh water will cause corrosion. I would still prefer to see this system set up as a boiler feed system, with separate pumps for each boiler controlled by the boiler water level -- not the condensate tank level. I presume this is steam, so I also presume that there are the usual overflow/spill traps for the two boilers feeding the tank, in addition to the returns. Both pumps can and probably should operate from a single receiver tank, if the system is common. If the returns are split, but not the supplies, then you could have two tanks -- but they need to be interconnected.