Vaporstat test problem??

trivetman

I got a new vaporstat and am in the process of putting it in. No need for heat now in August but the vaporstat instructions say you can test it by reducing the set point through a range greater than the differential at which point the made contact should break. It doesn’t seem to be working and I hope I just am misunderstanding the instructions.

What I think it should be is...If I start with my set point at 16oz (range is 0-16) and gradually turn it to 0 oz, my R-B contact should change from make to break at some point. It is not working. The R-B contact stays at make through the whole range. Ive done this for a few differential amounts from 2oz - 8oz with the same result.

Am I doing something wrong or did I get a dud vaporstat?

gerry gill

Most of the time the new vaporstats don’t even work. I have to put on a test rig and play with the calibration screw to get them to work. I hope Honeywell’s missiles work better than their heating products..lol

Fred

If you bought the right Vaporstat, it should break (based on your settings) at 16 ounces and make at anything below that. What model Vaporstat did you buy? It should be Honeywell L408J1009

trivetman

Yes that is the model number.
Honeywell L408J1009

I think you mean it should break when differential is 16 as I am starting my test with the set at 16. Likewise If I understand this test right, when I set the differential to 8 it should break when the set is at 8 or less. It is not doing this. Maybe I have one of the duds

JUGHNE

Are you trying to test this connected to nothing?
I believe you have to have some pressure applied to it.

trivetman

It does not have any pressure applied to it. The instructions do not say the test needs to be done under pressure. If it needs some pressure above the room pressure to perform the test than that explains why its not working.

neilc

with no boiler pressure on the vaporstat, it should be a made switch, calling the boiler on,
when the boiler pressure hits your cutout, or cutin plus differential, the stat (switch) should open and stop the boiler,
your test should be that you turn the main down till the switch opens(this at no boiler pressure, or "on the bench"),

trivetman

And if the switch stays closed when the main set is turned all the way to zero with no boiler pressure?

EBEBRATT-Ed

@trivetman

You can't test any pressure control without it being connected to a pressure source. You have to use low pressure to test a vaporstat.

How can you expect a control to work without any pressure?

trivetman

> @EBEBRATT-Ed said:
> @trivetman
>
> You can't test any pressure control without it being connected to a pressure source. You have to use low pressure to test a vaporstat.
>
> How can you expect a control to work without any pressure?

I’m just trying to follow the opaque (to me) test instructions in the manual, which don’t say anything about needing boiler pressure. I would not have thought to test like that if it wasn’t in the instructions. I figured I was probably doing something wrong which is why I posted. I’ll fire it up tomorrow to do a test with some boiler pressure.

neilc

trivetman said:

And if the switch stays closed when the main set is turned all the way to zero with no boiler pressure?

in my head it should open, but as others have said, these things need calibrating at times,
or possibly some minimal base pressure to trip that switch.

your wired in series with the other pressuretrol(s),
correct ?

trivetman

> your wired in series with the other pressuretrol(s),
> correct ?

Yes I did. Set a cross on top of a pigtail with the 0-3 gauge, v-stat, and pressuretrol wired in series connected to the 3 outlets of the cross

Steamhead

Here's the manual:

https://customer.honeywell.com/resources/Techlit/TechLitDocuments/65-0000s/65-0287.pdf

On page 6, under "If a Controller Seems to Operate Improperly"

the Vaporstat manual said:

4. Lower the setpoint of the controller (simulating a
pressure increase) through a range greater than the
differential. The switch should either make or break,
depending on the model of the controller. (See Table 1.)
If it makes, the ohmmeter will read zero; if it breaks, the
ohmmeter will read infinity.
5. Raise the setpoint of the controller (simulating a
pressure decrease) through a range greater than the
differential. The switch should break or make, just the
opposite of the result in step 4.

So, if we set the differential to 8 ounces, and turn the Main scale down to less than 8 ounces, the switch should operate.

I tried this on a Vaporstat that @Gordo tested, and the switch did not operate until I turned the Main down to 2 ounces. But the unit tested OK. Interesting................

mikeg2015

Mine seemed off compared to my low range gauge last heating season. I bought a manual pump bulb, a barb Tee fitting and I plan on testing and calibrating it with a manometer.

Jamie Hall

It's worth remembering that these things are microswitches, which have a very definite built in force difference between the two states. With no pressure on the diaphragm, it is possible that they may not transition even with the indicator set at 0; further, as @Steamhead mentioned, the transition pressure may not be the same as it would be with pressure on the diaphragm.

So, as has been said, the only really reliable way to test them, never mind calibrate them, is with a low pressure source and an accurate gauge.

I might also add -- be sure that you are using the correct terminals on the switch. The model you reference has both make on rise and break on rise contacts. You want the break on rise contacts.

trivetman

Dont hate on all the new Vaporstats. Now that its cooled down a bit outside I tested it out and everything checks out and is well calibrated out of the box

AMservices

How I check pressuretrol calibration.

mikeg2015

My vapor stat inverts the disc under vacuum. When the disc is not dented it’s actually fairly accurate.

I’m going to try a basic differential pressure switch for staging the burner. Probably set it to around 4oz for my system. (Regular pressuretrol At 1.5psi for the safety cut out.)

mattmia2

you could probably steal a bulb off of a sphygmomanometer to test. could make a manometer with some tubing too if you just needed it once

mikeg2015

I pickup up a cheap bulb designed for siphoning fuel and just use my manometer to check. The hat when I figured out the disc was popping/inverting. I have a vapor system with fairly large piping and with big mouths unable to break vacuum once closed it pulls hard into vacuum. I added a vacuum bracket but I think it’s cracking pressure is almost 1psi or more.

ChrisJ

I'm sure I'll get torn apart for this but,

What's the difference if a home steamer runs between 1 PSI and 1.9 PSI vs 0.5 PSI and 1.5 PSI?

Or 0.4 - 1.6 or 0.8 - 2.0?

All this talk of calibrating Vaporstats etc, and then I see them connected to a pigtail which I personally was never able to get work even remotely accurate at lower pressures.

Even so, does it really matter?

To me, for your average system as long as it shuts down somewhere around 1.5 PSI and starts back up about as low as you can get it but still have positive pressure, everyone is happy. It doesn't matter if its 1.25 PSI or 1. 75 PSI, the boiler and vents will never care.

Jamie Hall

Right you are, @ChrisJ ! There's such a thing as getting way too fussy...

The only thing I would add is that some systems -- of which Hoffman Equipped is an example, but so are some other vapour systems -- simply won't work as they are intended to work if the pressure goes much over 8 ounces. In fact 7 is better. And there, unless you are extremely well matched, you do need a vapourstat. And a low pressure gauge to calibrate it. And, if you lucky it's the old mercury kind, not the new-fangled microswitch kind, so you can calibrate it by simply tweaking the leveling...

ChrisJ

Jamie Hall said:

Right you are, @ChrisJ ! There's such a thing as getting way too fussy...

The only thing I would add is that some systems -- of which Hoffman Equipped is an example, but so are some other vapour systems -- simply won't work as they are intended to work if the pressure goes much over 8 ounces. In fact 7 is better. And there, unless you are extremely well matched, you do need a vapourstat. And a low pressure gauge to calibrate it. And, if you lucky it's the old mercury kind, not the new-fangled microswitch kind, so you can calibrate it by simply tweaking the leveling...

@Jamie Hall
What happens if you go over 8 ounces on a vapor system?
Return issues?

Jamie Hall

Depends on the system. On a Hoffman Equipped, the Differential Loop trips and closes the main vent -- and equalizes the pressure on the main and the dry returns. Eventually the loop resets and the steam in the dry returns condenses and heating resumes...

On some, if they have been modified, all that happens is that way too much steam bypasses the orifice or passive trap or other widget.

Either way, efficiency drops way down.

trivetman

> On some, if they have been modified, all that happens is that way too much steam bypasses the orifice or passive trap or other widget.
>
> Either way, efficiency drops way down.

This is what’s happening on mine prior to vstat