Adjusting automatic water feeder

tomsloancamp

I have a VXT 24 programmable water feeder and I wanted to know if there is any problem with adjusting the feed quantity. Currently it’s set to 2 gallons. The problem I am having is that the boiler is overfilling at that setting. I have to drain a gallon to bring down the water level to an appropriate level. Some information that might be helpful ... I have a slant/fin gas fired boiler and a McDonnell and miller low water cut off (probe I believe.)

Long Beach Ed

No problem. You select the adjustment that gives you the best result. Just remember that an automatic feeder is a safety and not a service device. If it's adding water regularly, your system is using excessive amounts, and you should correct the leak.

Adding excessive amounts of water on a regular basis introduces oxygen that tends to rot out boiler sections, some more than others. Check the manufacturer's literature for make-up water recommendations...

Jamie Hall

Somewhere on that thing -- check your manual -- there are two sets of DIP switches. One selects the amount fed per activation; the other selects the time delay between a low water signal and feed activation. Try setting to a smaller feed.

tomsloancamp

Thank you both @Long Beach Ed and @Jamie Hall for your advice. I believe I still have wet steam (I have condensation in the air valves) which might be the reason for the water loss. The water loss occurred last night when I turned up the thermostat. I had some loose connection (valve steams,etc) that I tightened and replaced washers with packing graphite. I am still trying to figure out the source of water loss but it doesn’t happen too often. Where is the ideal water level (via sight glass?)

Jamie Hall

"Where is the ideal water level (via sight glass?) "

Unless someone really messed up your installation, half to two thirds of the way up the glass from the bottom.

tomsloancamp

@Jamie Hall no mess up on installation, I just tend to have dyslexia or memory loss and could remember if it was 2/3 over or under half. Thanks for the reminder!

Long Beach Ed

We use an air compressor to check for system leaks. A fitting's piped for the compressor hose and we hook it up to anywhere on the boiler, usually the pressurtrol tapping after it's removed. The we walk around listening for the air leaks, which are easily found. One common spot is the sight glass packing nuts...

tomsloancamp

@Long Beach Ed I'm new at all of this so excuse my question but that method will help you find leaks in the entire system? Won’t the main vents and the vents on the radiator allow most of the air to be released? Again, I’m new to this so I might have questions with obvious answers.
Another question I have, on a single pipe system, what percentage of water loss is acceptable? It’s not possible that all moisture condenses and returns to the boiler (especially with 100 year old pipes!)

Long Beach Ed

We remove the vents and cap them for the test. Sometimes we thread the air fitting into a main vent hole.

Most boiler manufacturers specify the maximum safe amount of make-up water that can be added. Burnham, for example, advises not more than 2 gallons per year (1-1/2 pints/month) to be added to its five section (86K BTU) Independence boiler. That's pretty restrictive and takes a good leak-free system to attain.

Since water quality and its chloride content varies, manufacturers take a conservative stance with their specifications. The salts are one cause of graphitic corrosion which has plagued some boiler makers.

The point is to fix your leaks and limit your make-up water. A tight residential system can meet Burnham's requirements. One bad vent or leaky sight glass packing can invisibly leak great amounts of steam.