vxt makeup water feeder accuracy?

sreja

Hi all (nbc i'm talking to you!).



I've posted before at length about the large amount of water loss our system experiences (looks like we average about a gallon for every 2 hours of full power boiler runtime -- 400 gallons of makeup water so far this season).



[As I've posted about before in 14 unit 5 story building and almost all returns are visible, but there is maybe 200ft of return that is buried underneath a marble lobby that we cannot examine].



Anyway, we've already discussed at length elsewhere on the wall forum about why this is bad, and the difficulty of finding the leaks, i don't want to revisit any of that.



What I did want to discuss today is if anyone has any thoughts on the accuracy of the digital readout of gallons fed, on the vxt water fillers?



Our VXT looks like it's piped properly, and i have no real reason to doubt that it's accurately reporting the # of gallons fed -- in fact i love that little VXT.  But it does strike me as something i should at least consider before taking it at face value.



Does anyone have any experience with how accurate the makeup water numbers on a VXT are, and if there is any scenario where it might be overreporting them?



Regarding a scenario -- we do have a condensate pump and i've tried to imagine some scenario where the condensate pump could somehow be fighting against the pressure of the boiler and somehow forcing its water up past the vxt and into the water supply line.. but i can't convince myself this is possible, given that you can tell when the condensate pump kicks in that its going into the boiler as it often "collapses" the steam somewhat.



Just a thought.

nicholas bonham-carter

Greetings from Omaha to Chicago!

If you have a back flow preventer, then there should be no reverse flow into the water service line.

There should be almost no pressure in your system to overcome.

Can you dig down under the sidewalk outside the building walls and make a replacement return line that way to avoid damaging your lobby tile? Alternatively the returns could hug the ceiling until they are beyond the tile floor, and then drop down.

I hate the idea of all that fresh water rusting out the relatively new Peerless 211A!!

If I were to replace it now, I would go with three smaller atmospherics .--NBC

Mark N

Check with Hydrolevel

According to Hydrolevel, took 2 minutes to find.  The accuracy is + or - 15% with water pressure 20 to 90 PSI.

sreja

re: vxt makeup water feeder accuracy?

Thanks for the fast responses. +-15%, can't ask for more than that.

i knew it was a shot in the dark, can't blame me for trying.



NBC: I don't see any good solution that wouldn't cost an absolute fortune.



However, what we may try to do when i get up the nerve, is try to throw everything at the problem of identifying which line(s) are really leaking, since there are a couple of places that dip down under the lobby towards the boiler room.  I have my doubts that an IR will locate it, but i liked a recent post here on the wall that suggested cutting open the source of the return lines and filling with water and seeing if water level drops.



That might be worth the cost to see if we get really lucky and find that it's only one of the return lines that pass under the lobby that is leaking.  If *that* turned out to be the case, then it's at least in the realm of possibility that we could divert all or most of the return piping away from the one leaking return line to another nearby one.



That's a pretty big longshot, but it *might* be worth the cost to try to throw everything at the problem of trying to isolate the actual location of the leak.



Other than that, the plan remains the same: to wait and see how long the boiler lives with all this make up water attacking it daily, and make a judgement about what to do at that point.