Boiler Flooding Two Days In A Row, New Leak at Old Fill Valve

Alex_19

Hey Guys,



I have a Peerless WBV-03 oil-fired steam boiler with a VXT-120 automatic water feeder and a LWCO. The boiler, feeder, LWCO, backflow preventer, oil burner, and localized piping are nine years old.



Last week, power was disrupted for nearly three days due to the late October snowstorm. Until the disruption, the system appeared to be working without incident. However, about one day after power was restored, and after the house was successfully reheated by the boiler, upon firing up I could hear forced steam immediately emanating harmoniously from the radiator vents. Realizing this indicated a problem, I turned the thermostat down and descended to the basement to inspect the heating plant. Looking at the sight tube, I could not see the water level. I concluded the boiler was overfilled, and left it off five hours in anticipation of eventual draining.



I drained approximately 30 quarts out the boiler before I could see the level drop into view. I returned to the primary level and turned up the thermostat. Everything worked fine. I periodically inspected the sight tube the next day and the level was fine each time.



Today - two days later - I once again heard the forced steam and reinspected the boiler. Again, the sight tube confirms it is flooded. This time, I also observed a large drop of water at the old fill valve (this was used to fill the original coal-to-oil converted boiler and is approximately 30+ years old) This valve is not really used anymore since the new boiler and VXT automatic feeder were installed.



Earlier this year in May, there was a boiler flooding problem when the water main valve inside the house dropped while closed, although not completely closed, and members here on Heating Help thought crud may have loosened into the piping. However, the boiler continued operating normally after that incident was rectified.



Please assist me by advising me what you think may be causing this constant flooding of the boiler. I suspect it may be the fill valve which is now leaking, but you are the experts and I defer to your experience. Thank you so much for any assistance you can provide.

Hap_Hazzard

VXT

If your VXT is in series with the old fill valve, then the VXT must be overfilling the boiler. I can't quite read the number on the display, but it looks like 142. If so, that's a lot of water. When was the last time you reset it? Did you install this yourself? What are your DIP switch settings? Did you by any chance connect this to your hot water line?



If I understand what I'm seeing, it looks like there's a drop of water hanging from the stem of your old fill valve. That will probably stop when you tighten the packing nut. I assume this valve is left open now, so if the packing isn't tight it will leak because it's now exposed to full system pressure while the VXT's valve is closed, which should be most of the time. If you can't make it stop, replace it with a ball valve.



I notice this wasn't installed according to Hydrolevel's recommendations. They recommend using a bypass valve, two unions and a shut-off valve on either side. It looks like an elaborate setup, but it makes troubleshooting and fixing problems like this a lot easier.

Alex_19

Re: Boiler Flooding Two Days In A Row, New Leak at Old Fill Valve

Hey Hap Hazard,



I'll answer your questions, then give an update on what has occurred since my original post:



If your VXT is in series with the old fill valve, then the VXT must be overfilling the boiler.



I believe it is in series. I'm not a plumber, however, so not sure exactly what you mean. I hope the pictures can answer that better than I ;-)



I can't quite read the number on the display, but it looks like 142. If so, that's a lot of water. When was the last time you reset it? Did you install this yourself? What are your DIP switch settings? Did you by any chance connect this to your hot water line?



142. You are correct :-) And that is because I have not reset it in a long time. I did not install it, a sub-contractor from an oil company we used to deal with installed it and the boiler about nine years ago. Shortly after the original installation, there was knocking and scratching in the pipes and boiler flooding. I contacted VXT and they were very helpful with telling me how to adjust the settings. This stopped the knocking, scratching, and overfilling. I do not recall what the current setting is, but it was not changed. And this is not connected to the hot water line.



I should add that if I am home, I can hear when the VXT fills the boiler. The fills are about 20 seconds in duration and do not happen very often.



If I understand what I'm seeing, it looks like there's a drop of water hanging from the stem of your old fill valve. That will probably stop when you tighten the packing nut. I assume this valve is left open now, so if the packing isn't tight it will leak because it's now exposed to full system pressure while the VXT's valve is closed, which should be most of the time. If you can't make it stop, replace it with a ball valve.



You have good eyes :-) I suspect the fill valve has gone bad and have concluded it must be replaced. In fact, I have just returned from a hardware store with a ball valve in anticipation of the repair.



I notice this wasn't installed according to Hydrolevel's recommendations. They recommend using a bypass valve, two unions and a shut-off valve on either side. It looks like an elaborate setup, but it makes troubleshooting and fixing problems like this a lot easier.



I'm not surprised. Notice I said we do not deal with that oil company anymore? The installation, however, did pass the local code enforcement inspection. I do realize local codes are oftentimes behind the times and should not substitute manufacturer recommendations.



Now for my update:



Six hours after my post, the boiler flooded again. I drained another 30+ quarts. This time I slowly shutoff the old fill valve. I then tried the manual fill on the VXT and while it made an electronic sound, no water appeared to fill. I rechecked the boiler twice this afternoon and so far it appears no additional fill has occurred. Twelve hours have elapsed after shutting off the fill valve. There is no longer the drip at the valve stem.



I have lowered the thermostat and plan to use the boiler very sparingly until the fill valve is changed.



Based on these findings, is it possible that this failed valve is the likely cause of the flooding, or should I look further? Thanks again.

Jamie Hall

May I ask...

during our lovely snowstorm, did you get any power surges before the lights went out?  Or were you running a generator without its being properly grounded?  I only ask because of the chance that something in the VXT got fried, and is letting stay open after in is opened, instead of closing when it should...

Hap_Hazzard

Yes.

The old shut-off valve is still shutting off the flow to the boiler, so, ironically, it's okay, aside from the loose packing. Now that you've shut it off, the VXT can't feed water to the boiler, so it can't flood it either.



One of two things could be happening. Either the VXT is leaking, allowing water to enter the boiler even when its valve is off, or the low water cut-off is calling for makeup water too often. Since you said you heard it frequently (those things really hammer, don't they?) I suspect this is what's happening. I mean, if the boiler is flooding, but the LWCO keeps on calling for make-up water, that LWCO is the culprit.



Try disconnecting the feed wire from the VXT and turn the manual shutoff valve back on, then see what happens. If the water level goes up, you need a new valve for your VXT. If the water level goes down or stays where it is, the VXT is okay, but your LWCO has a problem.



Let me know what you find out and we'll take it from there. If you need a new valve for the VXT, you can get them for about $25 if you know where to look--much cheaper than replacing the VXT. If it's the LWCO, the fix depends on what type you have. If it's a probe type, you may need a new probe, but try cleaning it if you haven't already.

Rod

Boiler Flooding

Hi - I've been reading this over and it occurred to me that we are concentrating on the makeup water feed line and while it sounds like the vxt, haven't eliminated other possibilities.

There are generally only two sources for boiler flooding:



1. The "make up" water line either manual or through the automatic water feeder.



2. In internal coil which provides hot water for domestic use.



Does your boiler have an internal coil to heat water for domestic use?

If so this coil can develop pin holes leaks which results in the

flooding of the boiler. Do you have such a coil?



I think I would just shut the hand valve on the make up water feed line before the VXT and drain the boiler water so that it is at proper operating level and wait and see what then happens.

If water then continues to flood the boiler then the next step would be to replace the manual valve and also have the piping on the vxt redone to the manufacturer's suggested configuration. This needs to be done in any case and would now will give you 2 valves available to shut off the make up water supply. If you have an internal Hot Water coil and it then continues to flood, the coil is bad and would need to be replaced. There are replacement coils  available. I've attached the VXT manual if you don't have one.

Alex_19

Replying to your questions

Hey Guys,



Thank you very much for the replies. I have some answers to your questions:



During our lovely snowstorm, did you get any power surges before the lights went out? Or were you running a generator without its being properly grounded? No to both questions. There is and was no generator involved.



Does your boiler have an internal coil to heat water for domestic use? No.



The LWCO is a CycleGuard CG450.



@Hap Hazard: I'm not sure I understand what you meant by the following:



One of two things could be happening. Either the VXT is leaking, allowing water to enter the boiler even when its valve is off, or the low water cut-off is calling for makeup water too often. Since you said you heard it frequently (those things really hammer, don't they?) I suspect this is what's happening. I mean, if the boiler is flooding, but the LWCO keeps on calling for make-up water, that LWCO is the culprit.



I have only heard the hammering when the boiler has overfilled and this did not start until after power was finally restored. I can hear when the VXT fills the boiler, and have not heard this at all since the power failure and subsequent restoration.



Where is the valve located inside or on the VXT that some of you have suggested may be faulty? Could cutting power to the VXT after replacing the faulty fill valve help to determine if the problem still exists?



Thanks again.

Hap_Hazzard

VXT

The valve on the VXT is that thing on the back that the pipes are connected to.



Try disconnecting the feed wire. It's the middle wire in the terminal block inside the VXT. (Since this is 120V, turn off the power before opening the box.) If the boiler continues to fill with water, you need a new valve.



The valve is a 443P, made by DEMA Manufacturing. They're also used in pressure washers and various other machines. Last time I got one I got it from a guy who sells parts for those coin-operated car wash machines. They come with either 12, 24 or 120V solenoids, so you need to specify 120--or you can use your old solenoid. Make sure you get a 443P, not a 443. The 443 has a plastic valve body; the 443P is brass.



If you remove the two screws from the top and pull the two wires off the solenoid, the rest of the unit comes right off, leaving the valve connected to your plumbing. At this point you're going to wish they'd installed those unions, because it would have made it a lot easier to replace this valve. You might want to think about doing it the way they show it in the manual that Rod has provided when you put everything back together.



If you don't want to do this right away, you can just keep your manual shutoff turned off and check the level every week and add makeup water as needed.