Boiler Overfills Reason Unknown

J. Thaler

I have a Peerless Steam Boiler
Boiler # JOT 35-WU
Serial # 001-396-53

Having not used or checked it over the summer the burner tech came by for the annual tune up.

It was overfilled by at least two large buckets (10 Gallons ) The sight glass indicated this.

It has a hot water coil but it is no longer used as I have a seperate gas hot water heater.

The tech could not determine why the boiler was overfilled, other than a faulty feed valve. However there are two ball valves in series, could both be faulty ?

I remember reading about reasons for overfilling and perhaps a faulty hot water coil could cause this, however I do not remember the details.

I plan on changing one of the valves and see if it continues to overfill, does anyone have any other thoughts or explanation as to what is causing this ?

Thanks in advance.

Brad White_2

Is the domestic coil

disconnected from the water source? A pinhole leak can add quite a bit to the boiler.

I agree it is unlikely that two ball valve in series would both leak. However, depending on how much water is captured between the two ball valves, there may be another issue.

If water is captured betwen them and that section is full, Boyle's Law governs and may allow weep-by due to infinite pressure of a contained liquid. Not terribly likely but easy to eliminate as a factor:

1) Shut the farthest valve from the boiler first, (boiler off) and wait a moment. Then shut the second valve, with presumption that the intermediate pipe has drained.

or

2) Provide a tee and drain-off between the two. This is what is known as a "double-block and bleed" to prevent said problem.

Still, my money is on a connected but dormant domestic coil with a leak.

Biged

Boiler overfill

If the valve for the fill is not left open accidentally and they are ok then the only posible cause should be the coil, maybe has a slight leak in. Some times when they are no longer in use they are pluged at the coil outlet or capped at copper pipe coming out. this may cause the rupture maybe in just the same as water eats away at an anode rod it does the same to the coil maybe one of the experts could varify this. why not take and remove the cold water feed going into it.

Matt Undy

Other possibilites

Or you have an issue with something saving up condensate and returning it at a later time or filling with steam and condensate out in the system or a few other things. Look at this:

http://www.heatinghelp.com/steam_boilerisflooded.cfm

and here are some more genreal things:

http://www.heatinghelp.com/steam_problems.cfm

BTW, why are there 2 valves? Did one fail and another get added? Is there some common reason for it? If there is a union in the line you can crack it to check for leaking valves.

Matt

J. Thaler

I have no explanation for the reason there are two valves, maybe the answer would be to eliminate both and install a single new one.

The coil is disonnected from the cold supply.

I am leaning toward the theory of a slightly blocked return that is holding back condensate until it cools and then returns to the boiler causing an overfill situation.

When the boiler is hot and running, after shutdown the slightglass indicates a lower water level, water is periodically added, to maintain level, and then after cooldown or long period of time, overfill is indicated.

Does that indicate a blocked or partially blocked return ?

Thanks again for all responses, extremely helpful.

Matt Undy

Read Dan's link

It seems to indicate that the boiler should be filled cold. When the boiler is steaming there will be a siginificant amount of water in the system as steam and condensate. If you fill the boiler to the cold level while it is hot it will be overfilled when the system cools, the steam in the mains and radiators condenses and the condensate drains back.

I hope somone else can explain how to properly fill the boiler, parhaps its in the steam problems section somewhere.

Matt

Brad White_2

Matt's point has merit

in the heating season when, I agree, some condensate would hang up then be released such as by a vacuum breaker.

Because the over-fill occurred in the summer when the system was said to be down, the only source(s) of water connected to the boiler are the domestic water coil and the manual make-up water valves, JMHO. With the coil now said to be disconnected, that leaves those darn valves.

As an experiment, disconnect both. If water still appears, call the Pope and then set up facilities for the pilgrims sure to appear at the Shrine of St. Peerless of Eternal Water.

Dominus Vobiscum

jackchips_2

Hey Brad,

Et cum spiritu tu oh. LOL