Condensation/feed tank problem

vaponut

I am working on a residential two pipe system which stopped working. There is a 440K peerless steam boiler with a condensation feed tank. The boiler would not start. I found the LWcut off blocked, I cleaned it. still no go. i traced the low vol wiring and found that the vaporstat was not working. I removed the pigtail and made sure everything was clear replaced everything and the vapor stat still not responding. replaced vapor stat with same

set main at .5 lbs and dif at 6 oz this is the same settings the old one had. Bingo boiler started working. However banging in pipes ( which owner said was normal) . The atmospheric vent in the cond tank was spewing steam. I started to investigate the system and found thermostatic steam traps many of which wer buried in renovated walls and built in cabinets not accesible for checking or repair. I spoke to my supply house old stem guy and he said i needed a F&T stem trap. This would solve the problem, as the radiator steam traps werent working. The owner decided to leave this situation for a while. the system worked fine. I was called back and i installed the F&T. perfect no more steam escaping the vent, little or no banging. However the boiler would not start. found the second (probe type) LWCO which controls the condensation/ water feed tank not functioning. I replaced it against my vendor advice. He said this would not work. I said it had for years (over 10 according to the owner) thus i replaced . boiler worked fine watched it cycle and appeared to work fine. left received a call that the boiler never started after i left. BTW the pressure gauge is a 30 lbs type and a OZ type is not readily available. I tried changing the pressures and found that the manual reset pressuretrol had tripped. i eliminated the pressuretrol and watched the same thing happen again. no heat. Any advice

Steamhead

You probably don't need the tank at all

where did you put the F&T trap?

icesailor

Band Aids:

I'm not a steam expert but from what you describe, it worked at one time and now it doesn't. The system has been abused for years. You need to start from the basics. You need to find all the buried traps and vents and replace them as if it was a new system.

Others here will tell you what you need to do but adding a F&T trap sounds like a band aid on the infection. 5# pressure sounds like an attempt by a dubber who thinks that higher system pressure is the Holy Grail of troubleshooting steam boilers.

If the owner doesn't want to fix it properly, take a walk.

There's never enough time to do it right. But always time for someone else to do it over.

I've not seen this, but will that 5# pressure make the system create a multitude of scuzzola and foul the system? If the controls are failing, maybe that's part of the problem.

Jamie Hall

Square one

This is going to be a go back to square one and fix stuff.



First off, a two pipe steam system simply won't work properly -- if at all -- if it is possible for steam to get into the returns.  There are only two ways to prevent this: steam traps on every single radiator or crossover line, or restricting orifices or other controls on some vapour systems.  If there are traps on the radiators at the present time, it is of the first type.



Those traps need to be working, and if you are or were getting steam at the condensate tank at least one of them isn't.  Probably a lot of them.  If you can get access to them, they are easy enough to repair -- repair parts are available for almost all types.



Second, why, as Steamhead noted, is there a condensate tank at all?  These systems work just fine on gravity return, unless someone has gone and messed up something somewhere else, or not repaired something that should be repaired.  So the next thing to do is trace out all the returns -- wet and dry -- and make sure that they do, in fact, return as they should.



While you are at that, check that the near boiler piping, including header, equalizer, Hartford loop, etc. are all piped as they should be.



Vapourstats rarely fail, particularly the older mercury vial type.  So the next thing to do there is to make sure that all the boiler connections to controls -- vapourstat, pressurestat, low water cutoffs, sight gauge -- are free and open and, in the case of the pressure controls, properly equipped with pigtails which are also free and open.



Finally, two pipe systems need to be vented.  Again, there are two basic flavours; one type -- more common -- has vents on the ends of the steam mains (well, not quite at the ends, but very close); the other type has crossover traps between the steam mains and the dry returns, and a vent or vents on the dry return where it turns down to the boiler, usually very near the boiler.  If those vents aren't working -- or aren't there at all -- the system won't work properly.  If the system has been running at a pressure much over 2 psi for any length of time, the odds are that the vents are toast; ditto the traps.



So... back to square one here.  Nothing particularly hard, just detailed.

nicholas bonham-carter

Buried traps

Everyone who works on steam should have the most essential diagnostic tool of all-the 0-5 psi low pressure gauge.

What was the manual reset pressuretrol set for? Is the vaporstat a mercury switch type with pigtail oriented so it flexes with heat, and throws the unit out of level? Somehow the pressure is rising above the settings on the vaporstat, and tripping the secondary. Are they mounted well above the waterline?

How is the waterline-steady or jumpy? Pictures of the boiler would help.

This must be a big house with 25 big radiators, for such a boiler, or it is very oversized.

This maybe a vapor system designed to operate on 2 ounces.--NBC

vaponut

vaporstat

This sytem has electronic vaporstat main set at 1/2 lbs and dif at 6oz. Themanual reset pressure from is at 3 lbs. I did not install the feed tank. I did install the f&t there is no Hartford loop. The system worked before.

vaponut

skimmed the boiler first

Boiler skimmed. Most boilers I work on have simple pressuretrol one pipe systems.

vaponut

vapor systems

Wouldn't a vapor system have a pump?

Steamhead

Nope

these systems were designed to work without electricity, using a coal-fired boiler. They did not use return tanks and electric pumps.



Quite a few Vapor systems did use "Return Traps" though, but these only came into action if the boiler pressure got too high. Excessive boiler pressure would slow or stop the condensate returning by gravity, so the Return Trap took over and used the steam pressure to force the water to return.



Nowadays we have Vaporstats, so we can keep the boiler pressure low enough to allow gravity return.



Five pounds tells us the system has been knuckleheaded, and that it's using way too much fuel.



Where are you located?

vaponut

pressure

The pressure is not 5 lbs it is. 1/2 a lbs and the dif is set at 6oz. The pressuretrol is set at 3 lbs but is not connected. I can get it to run if I reset the main on the v-stat moving it up and back to 1/2 lbs

The pigtail is clear. The vsporstst does not have a mercury switch there is a vacumn breaker on the boiler next to the relief valve there are vents on the mains which seam to work the sport a little then close. I only added the f&t

vaponut

pressure

The pressure is not 5 lbs it is. 1/2 a lbs and the dif is set at 6oz. The pressuretrol is set at 3 lbs but is not connected. I can get it to run if I reset the main on the v-stat moving it up and back to 1/2 lbs

The pigtail is clear. The vsporstst does not have a mercury switch there is a vacumn breaker on the boiler next to the relief valve there are vents on the mains which seam to work the sport a little then close. I only added the f&t

Jamie Hall

Start with the boiler controls

and get them working at least.



You have four as I understand it: vapourstat, manual reset pressuretrol, and two lwco's.  One of which should be a manual reset.  Start off by making sure that all the pigtails and opening to the boiler are clear, which I assume you have done.  Also double check that the controls are properly wired in series.



Now.  Start the system.  Eventually pressure should begin to build a little.  When it does, the vapourstat should open and the burner should stop.  After a few minutes, it should reclose and the burner start up again.  If this doesn't happen, either the vapourstat is out of the circuit (it isn't paralleled with the pressuretrol, by any chance, is it?  Everything should be in series) or it isn't working.  Find out what the problem is and fix it.  Now move on to the pressuretrol.  Jumper the vapourstat out of the circuit and fire up.  The pressuretrol should open and say open.  If it doesn't, find out why and fix that.  Take the jumper off the vapourstat.  Double check that the vapourstat works as advertised.  Next check the lwco's; the burner should stop if either one of them senses low water.



Once you have that all straightened out, the boiler should fire up reliably when the thermostat calls for heat (assuming, of course, that the burner is working properly...).



Once you get that far, you can start working on the piping and traps.  As I noted before, a two pipe steam system, never mind a vapour system, simply will not work properly, if at all, if steam can reach through the radiators to a return.  An F&T can't and won't fix that.

vaponut

i have done everything you suggested

All lwco are as advertised. Vstat and patrol were wired in series and yes the boiler fires. Most rads get hot. Tstat still calls for heat. Boiler goes off at pressure ( I assume as the gauge is a 30 lb unit.and there was no 5 lb gauges available anywhere near me I have ordered one). The boiler does not restart and the p trol which is a manual reset does not reset. I removed the wires and just let it run on the vstat.same outcome. Here is the wiring sequence( all in series) lwco. At gage glass then to lwco probe type which operates the feed tank via an end switch built in. Then to the vstat next the patrol next burner any ignition. It almost seems like a vacumn however there is a vacumn breaker on the boiler next to the relief valve. It is brand new. Could the f&t be causing a vacumn? It just seems that the pressure is the problem. I have had problems in the past with the electronic vstats. I need to go drive an hour to the job to have more fun ( it is a little) if I didn't hav a customer so upset.

vaporvac

Gas valves;burners?

Jamie has brought up a good point. Given the state of delayed maintenance, we might assume lots of things aren't up to par. If everything noted above checks out, it could be that the problem is with the gas valve or the electricity leading to it.

I'm also a homeowner with a similarly large system. Due to age, my gas valve would only open sporadically leading to unmet calls for heat. In addition, the electrics controlling it had come loose adding to the problem. How old is this system?

Jamie Hall

Very odd

Does the vapourstat do anything?  It should open long before the pressuretrol does -- and reset within a couple of minutes.  I note in your first post that this is a replacement vapourstat; it would seem unlikely that a new one would be defective, but one never does know... getting a low pressure gauge is a good idea.  Then you can compare where the 'stat is set with pressures -- and with a multimeter and the cover off, you can see easily enough whether it's opening properly or not (one of the many reasons I like the old mercury ones is that you can see it operating -- don't have to do any fancy measurements!).



This kind of troubleshooting can be either frustrating or amusing, depending rather on one's mood (and on just how irate the client is...).



Keep us posted, please!

BobC

When things get to this stage

I find it's best to step back and examine everything again because it's possible you missed something. Trace out all the wiring and verify every single control, check every wire and switch to make sure it is what you think it is.



Something is not what it seems.



Bob

Pumpguy

A question for vaponut:

Can you tell us just where you installed this F & T trap?



Can you post a sketch or photo of the piping arrangement?



If you installed this F & T trap just ahead of the condensate return pump, this is called Master Trapping the system which is a definite NO-NO.  The reason being, when this trap closes, the pressure equalizes on both sides of the radiators, and without a difference in pressure, there is no steam flow.  And of course, with no steam flow, there is no steam heat.

RJ_4

boiler

Is the Peerless boiler a new replacement for an old boiler, the feed tank may have been installed to compensate for smaller water content of the Peerless boiler. I have seen some fitters install horizontal tanks at boiler water level to do the same thing, but alot of these installs are not to code. . As everyone else said , you need to find and repair or replace all system traps, If just 1 is leaking steam you will still have problems.  As pumpguy said dont put a F&T Trap ahead of tank on 2 pipe system.  F&T traps are good for removing condensate from large risers and steam coils to name a few applications.