New vaporstat
Just installed a Honeywell vaporstat L408J 1009. I set the main to 3 oz. and the Diff to 1 oz. The boiler is currently running just over 1 psi, and the vaporstat never cut out. I tried moving the Main screw up and down, but it did not do anything. Any help is appreciated. Thanks.
Comments
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I'm assuming you're reading the 1 pound on a fairly good low pressure gauge?
Take off the Vaporstat and test it by blowing through it. Make certain it works at all on a low pressure.
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I have a 0-3 psi gauge on there. Is there something special you need to do to the vaporstat before putting it in service for the first time?
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First off, that's a pretty tight setting — even for a vapourstat. I'd rather see 8 ounce main and 4 ounce differential.
However, that's probably irrelevant. Two things to check (assuming your pressure gauge is accuate — if it's the 0 to 30 psig gauge, it isn't). First, the pigtail into the boiler. If it's plugged, the vapourstat will never see pressure and will just sit there. Second, the wiring of the vapourstat. Is it wired into the circuit properly? Is the circuit wired through the open on rise contacts?
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England0 -
Everything is brand new coming out of the boiler. Nipples, unions, tees, elbows, brass pigtail tail etc. Just recently found out it's a Mouant vapor system and should only need 3-4 oz. of pressure. I meant to say the diff was set for 2oz.
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Could the wires be backwards?
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Breaks R & B on pressure rise. The connections photographed above are correct.
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If you are comfortable fiddling with it and you tried blowing through it, take the cover off and make sure the actuating lever is causing the switch to depress…
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To the left of the wire connections in the vapor stat down low you will see that steel plate whih is part of the trip mechanism.
Put a small screwdriver under that plate and gently pry that plate upwards with the burner running. You should here a click and the burner should shut off.
Your settings are a little off but you may have a bad vapor stat. Your wires are hooked up to R & B which is correct.
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How would I do that?
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I test all vaporstats/pressuretrols against a low pressure gauge. They’re rarely calibrated properly. There is a flat head adjustment screw (which it sounds like you’ll need to tighten) that is covered in the back of the vaporstat by a small circular plate.
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How do you access that?
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How do you access that? Also, if I turn down the main to 0, it won't trip the boiler
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@KJB basically the scales on any Honeywell pressure control are fairly inaccurate.
The first thing to do is with the boiler running use a screwdriver as I posted above to manually trip the vaporstat. That will prove that the wiring is correct and that the vapor stat switch works….you will hear it click.
Attached is the instructions. The check out procedure is in there. It doesn't tell you much except how to adjust.
If it doesn't seem to work you have 2 choices:
Return it
Or take it apart and fiddle with it. Its possible something came apart during shipping
If you take it apart you may not be able to return it and void the warranty
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Fixing A Failed Honeywell L408J 1009 Vaporstat - "Look Ma, No Mercury!"
https://youtu.be/BLpuWRmwVmYNational - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
Ha. I just found that video. Crazy it can be off that much. I'm glad they can justify $350, and it not even work properly out of the box.
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Ok. So I got the vapor stat as close as I can get it to the settings. I'll adjust more when I get a 0-16oz gauge. Was using a 0-3 psi gauge to fine tune it. Onto the next problem. 2 of my Mouat valves are leaking through and blowing through the water seal. Does anyone know where I can source a replacement valve? I'm aware of the orifice plates, but just want to explore my options. I know the valve has to be specific to the Mouat system.
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you can probably carefully rebuild the valve. An orifice plate in the union might be the way to temporarily fix it until the heating season is over and you can take the valve out to rebuild it on a bench. if you find a valve it will likely be used and you will have to rebuild it.
i think there are some nos hoffman vapor valves on ebay. i think someone also makes a new metering valve. unless your valves have something like a damaged casting or broken bellows if they are that style of packless valve, rebuilding them will be easier. The new valve won't be exactly the same size and you will have to change the spud in the radiator.
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Is an orifice plates a long term solution, or will it wear fairly quick? Here is a pic of the valve that is blowing through the water seal.
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Orifice plates don't really wear. If you close it part way does it not completely fill the radiator?
I'm not quite sure how that one works but there should be a stop in those holes that limits how far the valve opens based on the size of the radiator and therebefore how much steam it can condense. Ii'm not sure if it is a separate nut and screw that goes in the hole or it is in how this is positioned:
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That is a lovely valve. All you need to do to keep it from blowing through the water seal (I assume that you have already reduced the system cutout pressure to no more than 8 ounces per square inch, where it belongs on that system) is to partly close that valve… close it just to the point where the radiator gets hot almost all the way across on a long run, but not quite.
Those valves never wear out. It's all metal inside.
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England0 -
The handle seems to be the weakest part there, a lot of them rot or split and fall off. i wonder if you could find a wood or plastic knob you could drill a hole in and cut down to fit so you can turn it while it is hot. not sure if the original was wood or early plastic or hard rubber.
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I keep almost all of them closed. That one in particular is closed as much as it can be. I've moved it all around to see if it stops blowing through and no matter where the valve is, it still blows through. The water seal is just as hot as the steam valve inlet. Cut out pressure is roughly 4 oz.
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A better pic of the valve
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I have it closed as much as it can close, and the steam still rips through the radiator and right out the water seal.
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very odd. I'd be inclined — this summer! — to take it off the radiator and the pipe, and see if the internal valve is connected to the handle. Or if you're a little braver, leave it on and unscrew the mechanism from the valve body (the big hex nut under the punched plate). Be gentle. Take pictures. Use a very high quality box wrench if possible — don't even think of using a pipe wrench. You may need a backup wrench on the valve body.
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
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You're starting to scare me. Lol. The last thing I want to do is ruin it. The other radiator that leaks through has a round handle. Looks like a needle valve handle. There is only 1 other radiator in the house with that round handle, and that one does not blow through.
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Is it leaking anyway ? Drip at Yellow arrow.
To me its a DIY Summer project. Then there is time to figure it out. Meanwhile you can search for replacements, maybe used to rebuild while waiting for warmer weather.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
That pic was from when I had the pressurtrol and was running at roughly 1.5 psi cutout. With the new vaporstat, the boiler cuts out at roughly 4 oz. That valve no longer leaks at the lower cut out pressure.
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Looking again at those pictures… there's something not right about the way the rotation stops are set on that valve…
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England0 -
Do elaborate....
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So to add to the madness, I just went to check on the boiler cause it was about 66 degrees in the house and the stat was set to 71°. The boiler wasn't coming on. I turned it on and off, adjusted the main and diff on the vaporstat around and nothing. When I started to take the pigtail off, it when through the starting sequence, but only after I attempted to take the pigtail off. Brass pigtail, associated piping and vaporstat were all new as of yesterday afternoon.
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It's probably because you jiggled the vaporstat and it made its connection.
NJ Steam Homeowner.
Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
See my sight glass boiler videos: https://bit.ly/3sZW1el0 -
probably the vaporstat and its calibration. that design is kind of notorious for cutting out then never cutting in again intermittently if you have the main set too low on the non mercury switch version.
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Yeah and pressuretrols can fail in a similar way. They are all really bad.
NJ Steam Homeowner.
Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
See my sight glass boiler videos: https://bit.ly/3sZW1el0 -
If you have a Multi-meter I'd have verified the vaporstat switch was actually open, 24 VAC across it. You may have other issues that you are blaming on the vaporstat. With electrical stuff there is no guarantee that there is one and only one issue.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
I just came down and pushed on the metal plate to make the connection, and the boiler kicked back on.
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What would be considered too low? From what I'm reading and what I've been told, the Mouat system operates at very low pressure.....3 oz. or less
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the problem isn't the pressure, the problem is the mechanism in that vaporstat design. it gets a little iffy near the bottom of the scale. Dwyer makes some combination gauges and switches that some people like. If you go that route i'd wire it in series with the vaporstat but set the vaporstat a a high setpoint as a backup if the dwyer switch fails to open.
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Crazy that something that cost that much doesn't perform as advertised.
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