The case of the flooded boiler feed tank, this week's case

RayWohlfarth

A local brewer called and asked me to stop by. He said the boiler feed tank kept flooding and he was wasting both water and water treatment chemicals. The tank constantly dripped water from the overflow pipe. The constantly phrase got me thinking because if the water was trapped in the system due to blockages or improper piping, the flooding would typically occur about an hour or so after the burner started. This told me it was something else. What do you think the cause is?
I will be posting the video Friday and not offer any other hints till then. Thanks
Ray

mattmia2

The easy one would be that the fill valve on the feed tank is leaking a little.

Since it is a brewery I'm going to guess there is a HX out there somewhere in the system that is leaking potable water in to the system.

EBEBRATT-Ed

What @mattmia2 said.

or the feed tank is undersized

or partially plugged returns

Bill_Kitsch69

can we please have all available data.. why guess at things with no info? that is the practice that's wrong with a vast number of parts-changers and dart-throwers out in the field. with the info at hand, logically it's the feed water (float) valve is weeping; small possibility it's the feed water pump check valve, depending. but we know we don't have all of the info, so it's an exercise in futility. present the Case or don't present the case. What's the point of this game? It's not science. It's not troubleshooting.

yellowdog

the point is, it is a game that he does every week. relax and try to figure it out with the rest of us until his video comes out tomorrow morning.

Bill_Kitsch69

yellow dog, like I said, there's no point to the game. call me jaded.. in practice this practice demonstrates how in real life, too many cooks spoil the stew and shows most peoples willingness to jump the gun and assert their irrelevant theories - just like in the field - stifling and delaying real solutions in the field. it reminds me of wading through all the bull out in the field. I want to exercise and hone skills not stroke my ego. yellowdog.. that's leftist, right?

HVACNUT

Bill_Kitsch69 said:

yellow dog, like I said, there's no point to the game. call me jaded.. in practice this practice demonstrates how in real life, too many cooks spoil the stew and shows most peoples willingness to jump the gun and assert their irrelevant theories - just like in the field - stifling and delaying real solutions in the field. it reminds me of wading through all the bull out in the field. I want to exercise and hone skills not stroke my ego. yellowdog.. that's leftist, right?

It's a glorified Easter egg hunt. Have fun with it, or move on to another thread. Nobody's forcing you to play. And we always learn a lot from @RayWohlfarth, so why not a little down time?

retiredguy

@Bill Kitsch69; finding out the cause of a problem in a steam system is like a puzzle. The answer is not always the obvious, If it was, most of us would not have had a job. The obvious would be repaired and everything would be back to normal. In real life, that is not always how steam systems behave. I was in boiler room service for 40+ years and the easy fix was rarely the answer. Yes, most of the repairs are the same simple things, but in some cases, such as in a large high pressure system in a hospital, the answer may never be found. I know, I have been there as have others on this site. As you stated, "can we please have all the available data", as a service tech, we collect and disseminate all the data. We produce the data it is not written down on a note card and handed to us when we arrive at the job.

Ray is from the same town that I am although we never met. I enjoy trying to use my years of service experience to answer his questions. Even with years of experience the answers are not always the obvious.

My 2 cents.

retiredguy

Wow Ray, everyone beat me to the punch. Matt said that it could be the feed tank fill valve or a leaking coil in a HX. Ed said an undersized feed tank or partially plugged return lines. I will guess a bad steam trap or two or a bad boiler feed valve. It is probably not the obvious. Can't wait till Friday to see who gets the free dinner at Poli's Restaurant.

Johnder

I like to differentiate a condensate tank from a boiler feed tank. I usually think of a condensate tank as reservoir that keeps its own level by its own float mechanism and a boiler feed tank as a reservoir that feeds a boiler as a function of the level control on the boiler.  That said, if the boiler feed tank is always overflowing then the float control on the boiler (like a McDonnell Miller 42 or 150) might be calling for water but not getting it because the boiler feedwater line is stopped up to some degree yet water is still being introduced into the tank but a stuck make-up water valve.  Just a guess.

RayWohlfarth

Ok @mattmia2 was the right on the first answer but what caused the float valve to leak was the key. The installer didnt provide a PRV to lower the water pressure. The manufacturer stipulates a pressure no higher than 30 psi to the feed water valve. The building had a water pressure of 70 psi, more than double the pressure. This is surprisingly common on jobs and easily overlooked.

@Bill_Kitsch69 I like to provide a little more information than a service tech would get on a call from a customer. I know service techs will think about the possible solutions and repairs on the way to the job site.

@retiredguy I loved Poli's restaurant


This video marks a milestone for me. Its video #40 Thanks to all.

https://youtube.com/watch?v=r8-dyP3XDmk

jumper

Johnder said:

I like to differentiate a condensate tank from a boiler feed tank. I usually think of a condensate tank as reservoir that keeps its own level by its own float mechanism and a boiler feed tank as a reservoir that feeds a boiler as a function of the level control on the boiler.  That said, if the boiler feed tank is always overflowing then the float control on the boiler (like a McDonnell Miller 42 or 150) might be calling for water but not getting it because the boiler feedwater line is stopped up to some degree yet water is still being introduced into the tank but a stuck make-up water valve.  Just a guess.

Ideally there's an oversized reservoir high enough so that no feed pump is required. Motor starters wear out for one thing.

exqheat

The feed valve and the pressure reduction valve needs to be serviced cleaned and inspected annually. Rust can clog both. Be sure to put unions in when installing. Makes maintenance a breeze.

RayWohlfarth

Good point @exqheat Thanks