condensate tank overflowing

jclark

id like to start with thanks for reading my post, My main condensate tank has been overflowing with water ever since I started the system up this year. Please note this is a closed industrial application system. The pumps are working as the boiler levels are staying consistent. I only have three years experience with steam and have read a lot from Dan Holohan, This is the first year I've had this problem. Any advice for what to look for would be great or if I could answer any questions to help narrow it down as It is extremely hard to find anyone who actually knows what there doing with steam in up state NH, many say they do but their work speaks for itself. Thanks again

Snowmelt

what kind of heat, what kind of boiler and a picture. is it external tank?

jclark

kinda confused.... what kind of heat? Steam, The boilers are burnham v906a it is one of two external tanks... the main one near the boilers. trying to wrap my head around how more water could get into the system with out adding any... I checked both water feed valves to boiler and they work fine there is a water feed line in to tank on left side with gates which are off....

vaporvac

Try reposting this to the Strictly Steam for a better response.

Fred

Double check those valves. Just because they are off and appear to work doesn't mean water isn't leaking past the internal stops.

jclark

fred is my only option for checking those valves an ultra sonic listening device

Abracadabra

If you didn't have condensate pumps:
#1 - LWCO leaking
or
#2 - Manual feed valves leaking.

Since you have condensate pumps, if both of the above are 100% checked fine, and you have a automatic water feeder, there's a possibility condensate is not returning to the boiler quickly enough and the water feeder starts feeding water when levels in the boiler drop when boiler is firing.

I assume boiler does not have a DHW coil.

Fred

jclark said:

fred is my only option for checking those valves an ultra sonic listening device

Is there another "Main" water shut-off on that water feed line? If so, you can shut it off, lower the water level to where it should be and watch the system to see if the water level stabalizes.

jclark

alright I checked the low water cut off its fine there is no dhw coil on boilers the manual feed valves to boilers are fine I checked shut off gates to manual feed to tank and there fine and in off position. I appreciate all the help! As I was looking at the condensate return line to boilers, right before it goes into the boiler there is a one way valve, is it possible it is clogged or something and not letting pump push water to boiler?

JUGHNE

What tells the pump to come on? The boiler or the tank float?

If check valve between boiler and pump leaks when pump is off then boiler water could come back to tank. If pump control is in tank then pump would come back on and the water would see-saw back and forth. (pump short cycling)

I would be suspicious of any gate valve with some age and having been recently operated. Does the cold feed line before the gate valve feel cold or cooler than any other pipe in the area.?

Nagato1

The picture is hard to tell, however, from the sounds of it "being near the boiler" this might be a boiler feed unit.

One thing to keep in mind is boiler feed units are always controlled by the boiler level controller off the boiler. The tank will be equiped with either a solenoid makeup valve or a float operated makeup valve. These are made to ensure the feed tank has at least 25% water in tank at all times.

1) I would check to see if any check valves are broken down stream (I didn't see any in the picture). These check valves are designed to stop water from flowing back into the tank causing it to flood. If they have been recently replaced, make sure they weren't installed backwards.

2) Make sure the makeup valve is not stuck or broken. This valve is designed to bring in freah makeup when the tank level gets low. If it's stuck or broken, too much water could enter the tank causing it to flood before the boiler calls the pumps to run. Having that been said, this may not be the issue considering the OP said the valve appears to be "closed" which I wouldn't recommend doing.

Hopefully this helps.

Abracadabra

Unless I'm misunderstanding you, the boiler water level stays same and the condensate tank overflows? The boiler can't magically make water. It has to be fresh water being supplied to it.

jclark

alright, thanks for all the advice! yes the boiler tells pump when to come on I should also say we have another condensate tank in the middle of the shop which pumps water back to main tank, I felt all lines before and after gate valves and opened and closed them they seem to be fine, however I did feel the condensate lines between pump and boilers and one is considerable hotter than the other feels like the line from boiler 2 is allowing water from boiler back to tank which is hard to believe because there is 3 check valves in-between pump and boiler. As far as I can see in water gauge the level appears to be the same I have noticed when boiler has fired the water in gauge fluctuates/ surges. there is only 3 ways water can enter system I turned off main and tank water still rose. feel like im going crazy.

jclark

I just turned boiler 2 off and pump 2 , shut gate on the condensate line between boiler 2 and pump and took measurement of water level in tank will check on it in a few hours

jclark

update. the tank level actually went down a little the water level gauge on boiler 2 went down a little with it off the pipe is now cool enough to touch the piping is probably 20 years old an I know that there are 3 check valves on the line but I guess their all faulty. is it better to replace them or open them up and see if I can unclog them? I always feel if you have to ask that question you should just replace them. on another note why would some one put 3 check valves on that line?

Nagato1

Might want to check the check valves. Make sure they are operating properly and there is no sluge build up. If you have a strainer on the tank inlet, check that too and make sure its clean.

Not sure why there would be three checks on that line feeding the boiler. I would think that (1) would be enough.

jclark

Update, the problem was the check valves were failing do to sediment build up. drained cleaned/scrapped out condensate tank replaced 1 check valve and I pipe. cleaned up other two checks and no longer has overflow problem. Thanks for all your help, and hope this might help someone else in the future.

DerekH

You either have a steam trap blowing through near by or a check valve off of the main condensate return line that needs to be looked at. Possible that the swing gate fell off or is letting condensate from other areas flow back to your tank. 

JUGHNE

Check the date ......2015.
We hope he has it fixed by now.

Keep responding to other postings though.
Welcome aboard!