Can malfunctioning vaporstat be fixed?

GBC_illinois

Short version: My vaporstat seems to be going bad after about 18 months. Its the 5psi version, which I've been using at about 12 oz of pressure. Is there any maintenance I can do to fix it, like lubricating it?

Backstory: When the boiler was replaced in my 1920's era condo building 10 years ago (before I ever lived there), with a Weil Mclain LGB-9, the HVAC geniuses who installed it decided to set the system to a whopping 7psi, and used pressuretrols exclusively. There were so many problems with the boiler and radiators that after I moved in, I had people tell me I should sue the seller for not disclosing all the issues. Anyway, the majority of the problem was that the boiler pressure was set too high. *10 times* too high. After some self-training on the boiler, I discovered it would effectively heat the building at 12oz of pressure, and the water hammer and other issues were gone. So, I replaced the pressuretrol with a vaporstat, but the vaporstat I picked was the 5psi version, because I wasn't sure enough that I could run on sub-1psi pressure at the time. Anyway, after 18 months the vaporstat seems to be acting up. It lets the pressure go much higher than 12oz, but when I tap on it aggressively after it gets above the set pressure, it seems to unstick whatever is stuck in it, cycling the boiler off. Then the boiler fires again, and it goes over pressure again until I tap on the vaporstat. Other times, it cycles as intended.

So, it seems like something is sticking in there. Is there any way to lubricate it? Or any other maintenance I could be doing to salvage it? Is the 12oz pressure setting simply too low for the 5psi vaporstat?

If I have to replace it, I plan to get the 1psi vaporstat this time. It would be a shame if I have to replace these every 18 months though :-(

Mad Dog_2

You've experienced the Post-Mercury Version of the Vapostat!  I save the old Vaporstats, pressure tools and T 87s...I wouldn't waste your valuable time. Buy a new 160z max version (?Steamhead...model #?? Ha ha) off of Supplyhouse.com.  their prices are fair, service outstanding 👏 return policy the best...Honeywell made a whole bad run of them for awhile.....Mad Dog

GBC_illinois

Mad Dog_2 said:

You've experienced the Post-Mercury Version of the Vapostat!  I save the old Vaporstats, pressure tools and T 87s...I wouldn't waste your valuable time. Buy a new 160z max version (?Steamhead...model #?? Ha ha) off of Supplyhouse.com.  their prices are fair, service outstanding 👏 return policy the best...Honeywell made a whole bad run of them for awhile.....Mad Dog

I buy all of my boiler parts from Supplyhouse!

And yes, I've been reading about the post-mercury Vaporstat tragedy :-( . All the same, if there are any tricks any of you guys know, I'd be happy to tinker with it.

mattmia2

It is to some extent a safety control, i don't think i'd screw with it too much, at least not without teeing in the old pressuretrol as a safety in series.

Mad Dog_2

I guess if you got time to tinker, you can take it apart and play with the calibration but ZERO guarantees you'll not ruin it permanently.  I have found, in close to 40 yrs doing this, older, Pre-Mercury ban P trols  & Vaporstats almost never go bad..  very rarely. That being said, I've never done anything more than adjust it or fix the springs.  You're time could be spent doing something with much greater positive results.   Mad Dog 

bburd

Are you certain that the pigtail is clear and the vaporstat is actually seeing unobstructed boiler pressure?

109A_5

Hello Fdarby82,

Many things you could do, depending on your skills.
Just replacing it is the simplest and most typical resolution.
Replace it with a Mercury version (if you can find one).
Depending how handy you are, tinker with it, build a test setup for maintenance (YouTube videos for examples), replace the micro-switch inside it.

If it was me and my boiler needed active pressure control supervision. I would have a Honeywell device (Vaporstat / Presuretrol) wired in series for overall safety (and show), for normal cyclic pressure control operation it would never trip.

I would use a Dwyer pressure switch device for the pressure control. Many to choose from. A single switch and a separate delay timer (minimize switching cycles on pressure). Or a unit that has a two switches to set up a differential pressure control. I believe the Dwyer equipment is more reliable, durable and probably more accurate. If bought new probably way more expensive than the Honeywell stuff, however there is a lot of options on the NOS and used market.

The down side with Dwyer equipment is if you are not handy with electrical devices the difficulty of installing and setup may be overwhelming depending on what product you choose. And some require a separate power source.

It all depends on your electrical skills and how much you want to confuse the next boiler Tech.

My boiler never goes over 2 inches of water column (1.16 Ounces), so I don't need any pressure supervision other than for safety issues.

Jamie Hall

Before you get all wound up on this -- although it could be a problem with the control -- make sure that the pigtail is clear all the way through into the boiler and that the opening into the base of the vapourstat is also clear.

GBC_illinois

We do have a secondary pressure controller in series, (a pressuretrol), so that is what is currently preventing the high limit pressure controller from getting tripped. As far as cleaning out the pigtail: 

We have a control tee (or is it tree?) with all the gauges and pressure controllers. How does one inspect that to make sure it's clear? Should I just open the plugs, drain the water out of the tree, and use pipe brushes? (Btw I know I have to fill the tree with water again when I'm done to create a steam trap). Is there something specific I should be looking for when doing this cleaning?

Separate question: you recommended a pressuretrol specifically as a backup controller in series. Are pressuretrols less prone to failure than non-mercury vaporstats?

mattmia2

I just recommended the presuretrol because you already had it. But you already have a manual reset safety control anyhow.

Jamie Hall

That arrangement of control piping very rarely gets blocked -- so it's unlikely to be the source of the problem. Sadly, it's more likely to be in the vapourstat.

As to whether the pressuretrols are more or less likely to fail or get out of calibration -- not really. The basic mechanism is pretty much the same in all of the microswitch types; the differences are in the diaphragm used and the springs.

GBC_illinois

I ordered a new one, the 16oz Vaporstat. With any luck, maybe this version will last longer than the 5psi one I have now , with the low operating pressures I've set it to. 

GBC_illinois

Jamie Hall said:

That arrangement of control piping very rarely gets blocked -- so it's unlikely to be the source of the problem. Sadly, it's more likely to be in the vapourstat. As to whether the pressuretrols are more or less likely to fail or get out of calibration -- not really. The basic mechanism is pretty much the same in all of the microswitch types; the differences are in the diaphragm used and the springs.

Do you have advice on how I can independently test the functionality of each of my three controls, with the control tree arrangement I have?

neilc

that trap assembly in kinda upside down,
your water seal, which you ask how to replenish, is the long horizontal that all the trols and gages are nippled into, you would just drop water, lots of water, down into that upper back tee plug,
odd too is the 2 gages, one pegged, the other at 0, makes me suspect that horizontal is plugging at or in the nipples,
could be your issue at the trols also,
check and clean that long horizontal, and each of the nipples into it, check the bottom holes to the trols, and the gages as mentioned above.

GBC_illinois

neilc said:

that trap assembly in kinda upside down,
your water seal, which you ask how to replenish, is the long horizontal that all the trols and gages are nippled into, you would just drop water, lots of water, down into that upper back tee plug,
odd too is the 2 gages, one pegged, the other at 0, makes me suspect that horizontal is plugging at or in the nipples,
could be your issue at the trols also,
check and clean that long horizontal, and each of the nipples into it, check the bottom holes to the trols, and the gages as mentioned above.

The picture isn't very clear, but I have two gauges because of the low pressures I operate at. One is a 30psi gauge which is required by my local code. Of course, at sub-1psi, it barely moves. The other is a 32" WC gauge which has the accuracy I need below 1psi. I have a valve installed on each gauge -- which I keep off except when reading them -- to minimize the chances of blowout (especially the 32" WC gauge, which you can see in this pic is near the max of it's capacity now that my vaporstat has malfunctioned).

I do know how to refill the trap, but I appreciate your detailed explanation nonetheless! Seems like I have conflicting opinions here about whether the control tree is likely to be clogged, but I might try clean it as you detailed anyway.

Here's a full res pic of the gauges:

Chris_L

You can easily test the Vaporstat if you have a squeeze bulb. Remove the right branch of your tree with the two gauges on it, and the Vaporstat. Replace the high pressure gauge with the Vaporstat, and attach the squeeze bulb (or other source of air pressure) to the end of branch where you disconnected it.

You can then test the cut-in and cut-out using the squeeze bulb. You'll need a higher pressure gauge to do the same test with the Pressuretrols though.

And while you have the branch off, you can see how clear the long horizontal line is. Remove the few other plugs to check the other branches back to the boiler.

109A_5

Hello @Fdarby82,

Fdarby82 said:

Do you have advice on how I can independently test the functionality of each of my three controls, with the control tree arrangement I have?

I would say it is best to test them off the boiler one at a time. To test them on the existing manifold in place would require a valve to isolate the manifold from the boiler, then pressurize the manifold. This valve could inadvertently disable the safety features of the devices, since if the valve is left closed the safety devices can no longer see the boiler's actual pressure. You could use boiler's pressure and your low pressure gauge but that is a slow process especially if you want to cycle the switch a lot.

Honeywell L404F-1367 Steam Pressuretrol - #@&$% TRASH!
https://youtu.be/3AnN99dfxgY

Checking a Honeywell Vaporstat with custom rig and ohm meter
https://youtu.be/3dBTUp7SAMo


There are more videos if you look.

GBC_illinois

109A_5 said:

Hello @Fdarby82,

Fdarby82 said:

Do you have advice on how I can independently test the functionality of each of my three controls, with the control tree arrangement I have?

I would say it is best to test them off the boiler one at a time. To test them on the existing manifold in place would require a valve to isolate the manifold from the boiler, then pressurize the manifold. This valve could inadvertently disable the safety features of the devices, since if the valve is left closed the safety devices can no longer see the boiler's actual pressure. You could use boiler's pressure and your low pressure gauge but that is a slow process especially if you want to cycle the switch a lot.

Honeywell L404F-1367 Steam Pressuretrol - #@&$% TRASH!
https://youtu.be/3AnN99dfxgY

Checking a Honeywell Vaporstat with custom rig and ohm meter
https://youtu.be/3dBTUp7SAMo


There are more videos if you look.

These videos are very helpful! I thought about adding the valve to my tree too, but I had the same concern you mentioned: human error of leaving the valve closed, disconnecting all the safety controls from the boiler in normal operation. This could easily happen, and its a shared condo building. I think I'll build a test setup like shown in your video.

GBC_illinois

Chris_L said:

You can easily test the Vaporstat if you have a squeeze bulb. Remove the right branch of your tree with the two gauges on it, and the Vaporstat. Replace the high pressure gauge with the Vaporstat, and attach the squeeze bulb (or other source of air pressure) to the end of branch where you disconnected it.

You can then test the cut-in and cut-out using the squeeze bulb. You'll need a higher pressure gauge to do the same test with the Pressuretrols though.

And while you have the branch off, you can see how clear the long horizontal line is. Remove the few other plugs to check the other branches back to the boiler.

Thanks for this detailed explanation! Unless I'm missing something (I'm not a plumber), I don't think I can just disconnect the whole part of the tree at once because I don't have clearance around the tree to spin that section without first disconnecting all the nipples. So, I think I'll just build a test setup like shown in the videos posted by 109A_5.

109A_5

Hello @Fdarby82,

Fdarby82 said:

I think I'll build a test setup like shown in your video.

As much as I'd like to take credit for the videos they are not mine, I believe they are @Gordo videos.

I just like to use on-line information like that since it is efficient for all.

GBC_illinois

I had one more thought about making an "easy" test setup to validate the functionality of my boiler controls: If I add a pipe union to the "trunk" of my control tree coming off the boiler, I could in theory remove the whole tree at once, and then connect that trunk to a squeeze bulb for testing all of them at once. If I'm right, this would involve a lot less disconnecting and reconnecting pieces, (and all the associated re-taping / re-doping the pipe threads). Does that work?

109A_5

Hello @Fdarby82,
That method could be made to work. You probably would still have to disconnect the wires to actually test the switches, just because they 'click' does not mean they work correctly. And the heat would be off too. I guess it depends on when you want to do this.

If you did them one at a time and capped the open pipe you still could have heat by connecting the disconnected wires from each device one at a time. Be careful and and shut of the power when working with the wires there could be 120 Volts there.

mattmia2

You could make the test rig out of pvc, the fittings are cheaper and it would be fine at the pressures you are dealing with.

I'd have to double check, but i'm pretty sure the code prohibits a valve between the control and the boiler.

A couple unions could work but they would have to all be the same since they aren't standardized, one manufacturer doesn't fit another.

GBC_illinois

mattmia2 said:

You could make the test rig out of pvc, the fittings are cheaper and it would be fine at the pressures you are dealing with.

I'd have to double check, but i'm pretty sure the code prohibits a valve between the control and the boiler.

A couple unions could work but they would have to all be the same since they aren't standardized, one manufacturer doesn't fit another.

I had forgotten PVC was possible with a test rig. I will do exactly that. Thanks for the recommendation!

I won't be doing the valve between the boiler & controls -- too dangerous and I'm sure you are right that it will fail inspection.

Mad Dog_2

I know you are talking very low psi test, but be careful. PVC under alot of air pressure can shatter and send sharps shards flying.  I haven't seen it in a while, but I could swear its against code to test pvc with compressed air because of this possibility.   Just beware. Mad Dog