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It still needs to be blown down every week

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Steamhead
Steamhead Member Posts: 16,894
but we now have a 21st-century replacement for float-type low-water cutoffs and feeders that are mounted on boiler sight glasses.



This is a McDonnell & Miller #51-2 that someone had really kludged onto this older American-Standard atmospheric. It didn't have proper equalizing piping- the top was tied onto the Return Trap steam line and the bottom went to the boiler's return tapping. The blow-down was a gate valve that you couldn't open and close quickly, which didn't allow for properly clearing the mud from the unit.



Somehow it worked all these years. But the system developed some leaks and the #51-2 got to the point where it didn't always shut off fully. Time for a new one.
All Steamed Up, Inc.
Towson, MD, USA
Steam, Vapor & Hot-Water Heating Specialists
Oil & Gas Burner Service
Consulting

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  • Steamhead
    Steamhead Member Posts: 16,894
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    The new one

    is a Hydrolevel #724-CF. It uses two probes to establish a decent differential so the feeder doesn't kick on and shut off too quickly.



    As long as the water level is between the two probes, the burner will fire. If the level drops below the lower probe, the 724-CF will stop the burner and call the feeder. Once the water level has reached the upper probe, the LWCO starts the burner and ends the call for water.



    There is a 1/4" tapping in the top of the unit for installing a pigtail, pressure control and/or gauge. The unit can be mounted on either side of the sight glass, and the blow-down is a standard 3/4" full-port ball valve. Note that the blow-down valve is not included with the unit, so you have to provide it. Hydrolevel tells us they have had cases where knuckleheads have plugged the blow-down tappings and the units have filled with mud. This is obviously NOT a warranty situation.



    Hydrolevel makes a unit with a feeder built in, the 724-WF, but we prefer to pair our LWCO units with Hydrolevel VXT water feeders as shown here. There's no substitute for a counter when it comes to troubleshooting system leaks. For 120-volt operation, the model numbers are 711-CF and 711-WF.



    There were a couple glitches. The probes weren't properly screwed into the housing, resulting in a small leak. The quick-hook-up fittings weren't all there, and the copper tube that attaches to the top sight-glass tapping was out of round. We'll pass these along to the Hydrolevel people as soon as we can.



    Since the house has a programmable thermostat that runs off the 24-volt circuit, we had to install an isolation relay so the stat could still receive 24-volt power if the LWCO tripped. No big deal, we keep these relays in stock.



    The boiler ran nicely and the new LWCO and feeder worked without a hitch. Sure, we still need to blow these units down every week, but they work with no moving parts except a relay. That alone should make them a lot more reliable than the old-school float-type units.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • Long Beach Ed
    Long Beach Ed Member Posts: 1,212
    edited February 2012
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    Haven't seen that one...

    Thanks for sharing.   A shame the old 51-2 was destroyed by neglect.  Always thought they were cool looking controls.



    That looks like a cast iron manifold the new one sits in.  Hydrolevel makes several manifolds like that but I hadn't seen one with quick connects for a sight glass.



    Seems like a nice control that lets you disassemble and clean the probes.   Nice unit for a backup on those boilers without extra tappings too.
  • Thanks for sharing....

    I wasn't aware of this product and it will be a nice addition.  I've wondered about something like this on and off for a while. 

    There was an error rendering this rich post.

  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
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    Missing parts

    It might not be Hydrolevel's fault. I once ordered a VXT-24 and got a VXT-120 in a VXT-24 case and box. I hooked it up and wondered why it didn't work, then I noticed the transformer on the circuit board. I don't think Hydrolevel would have shipped it that way, and the box looked like it had been opened previously, so I think someone had returned it to the dealer that way.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • Gordo
    Gordo Member Posts: 857
    edited February 2012
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    We Also Ordered

    the 120 volt version just to have it in stock.  As with the 24 volt version, the brass work all came sealed in a blue plastic bag.  It too had a random assortment of  mismatched fittings and nipples, so that tells me they got issues with packaging.  We'll be checking the probe tightness on our 120 volt version, too.  The probes all had "teflon" tape on them
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
    https://heatinghelp.com/find-a-contractor/detail/all-steamed-up-inc
  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
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    probes all had "teflon" tape on them

    I used to design electronic stuff used by the US Navy. The navy was pleased we used Teflon-insulated wire in our stuff because our stuff had to work from -55C to +85C to pass an environmental spec. Teflon is a very good insulator. How is a probe-type insulator supposed to work with teflon insulating the device from the return ground?



    THIMK and the world THINKs with you. GAFOO and you GOOF alone.
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
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    For the record...

    Apparently DuPont is very upset about people throwing around their trademark whenever they talk about PTFE or fluoropolymers in general, so they've launched a big campaign to educate the public. They want us all to know that they have never manufactured plumber's tape nor licensed their product or trademark for any such purpose.



    It makes me chuckle, but I guess they have a point. I recently bought a package of packing rope that actually said "teflon" right on the package, but there was no "TM" or "(R)", and the DuPont name was nowhere to be found.



    Maybe we should all xerox that article and scotch tape it to the wall, right next to the kleenex dispenser. :-)
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • Gordo
    Gordo Member Posts: 857
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    Educating the Public?

    Hummm.  I think it's more like a case of enforcing the trademark.  If they don't do this "educating"  periodically, they'll lose it .  I'd say they already have.  Their lawyers have a big headache on their hands.  They'll have to take aspirin.
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
    https://heatinghelp.com/find-a-contractor/detail/all-steamed-up-inc
This discussion has been closed.