Faulty pressurestrol or gauge

Ying

blew the compress air when i was cleaning everything and making sure the connections were not clogged before I put on the new pigtail last week. You think that might have broke the pressuretrol?

Thermostat is a Honeywell 1 Week Programmable Thermostat with 4 different temperature setting periods for the day. When it is calling, temperature is set at a constant. There are not setback option.

Boiler is definitely over-sized, we had 2 radiators removed when we redid the house and turned those spaces into closets and storage space on 1st and 2nd floor.

Is oversize boiler my issue for the readings at the gauge? Don't want it to be same after I put in a new pressuretrol.

Might as well try to recalibrate the existing one if I intend on replacing it anyway, @Fred are the instructions you posted for the L404F1367 model? Can't seem to locate the hex screw you are talking about.

Thanks again

ethicalpaul

- no one can tell if your compressed air broke it—just don’t use it on the next one 😅

- no matter how oversized a boiler is, the pressuretrol should shut it off at the cut-out pressure

- the hex screw is so tiny it’s tough to see the hex part! But as Fred said, I wouldn’t mess around, you need a good pressuretrol. The adjustment I’m pretty sure isn’t meant to be used except at the factory which is why they put strong loctite on it and don’t document it

Jamie Hall

The maximum surge (instantaneous) pressure for the newer pressuretrols is 50 psi. Anything over that will rupture the diaphragm. Did you go over that with the compressed air? Hard to say. The only way to find out for sure is to rig up a little test rig with it in which you can vary -- and measure -- the pressure and see where it switches, if it does.

The oversize only influences how long it takes for the pressure to rise -- not what it will rise to. If the boiler runs with the pressuretrol out of the circuit -- one wire disconnected completely -- then the pressuretrol isn't switching.

Fred

@Ying No those instructions are for the 404A. Sorry, I don't know how/if your model can be calibrated.

Ying

Upate on the situation, put in a 0-15 psi on the pigtail with the pressuretrol. Skim the boiler via the pressure relief value for 2 hours at the same time.

The new gauge readings match the 30 psi gauge thats already there. So confirmed, honeywell L404F pressuretrol is toasted.

Took the cover of and watch the pressuretrol to see it working or not working. Diaphragm does push up the operating lever due to pressure. So play around with the operating lever and the scale. Looks like there is a disconnect somewhere between that scale and the operating lever, as changing the adjusting screw have no effect on the cut in and cut out pressure.

As I don't have a replacement pressuretrol on hand, decided to do so out of the box fixes. I started stuffing thin sheets of paper between the lever to assist the leverage.

That did change the cut off psi but somehow cutin remains at 2-2.5 psi.

I was able to get the following 2 results that is somewhat ok to me.

Boiler cut off between 5-5.5 psi, 3 minutes for psi to drop to 2-2.5 and boiler will fire up then reach 5-5.5, and bolier cuts off. Cycle repeats at this rate.

Also able to get the cut off to 3 psi, but cut in still stays at 2 psi. So it will be 1 minute 15 second with boiler one to get to 3 psi to shut the boiler off and 1 minute for the psi to get to 2 that will turn the boiler on.

Which cycling is better for the system? I kind of want the extra psi push as I don't have a main vent.

It did take about 20-25, since boiler was off for 2 hours for the system to build any pressure. About 5 minutes for the steam from the cold start to reach the end of the main pipe. So, I think system is doing petty well without a main vent. Maybe the C vent valve on the radiator right on top of the end of the main pipe helped with venting the air in the main pipes.

Fred

Given a relatively short time, any system pressure over about 3PSI will ruin most, if not all of your vents.

The higher the pressure, the slower steam moves so you don't want higher pressure because you don't have main vents. You want main vents. that higher pressure is just exacerbating an already bad situation.
A 0 _15 PSI gauge isn't much better than a 0 - 30 PSI gauge. You need a 0 -3 or 0 - 5 PSI gauge.
gerry rigging the Pressuretrol is not good either. It is not reliable or safe.
If you need a Pro to fix this system, call one. Look on the "Find a Contractor" tab at the top of this page and see who is in your area.

Jamie Hall

OK. First, as @Fred said, anything over 3 psi will ruin your vents; I'd plan on replacing them all now, since they have already been overpressured.

Then, before you turn the boiler power back on, get a new, reliable pressuretrol on there. What you have now is unsafe, unreliable, and will have no insurance coverage if something goes wrong -- you are now liable for any damages which might occur.

While you are waiting for the new pressuretrol so you can turn the system back on, figure out how to put main vents on the system and do it.

Set the new pressuretrol to 0.7 psi cutin, 1.7 psi cutout (1 psi differential).

Ying

Yeah, pressuretrol ordered and and on its way, just did to held over the next day or two till the new one arrives. Will need to add another gauge to that order then.

As for the repiping and putting in a main vent, waiting till it gets warmer. I have a good idea on how to get it done, hardest part will be cuting out a pipe to replace it with a union so I can work on just that section of the pipe.

Going back to the main vent. Will it make a difference in the cycle time? I've reached out to someone who just replaced their old not working main vent with a big mouth, I think thats what it is called, and the results are about the same as my current time. 25 minutes from cold start to get to 2 psi, then about a minute to drop to .5 psi and 1.5 minutes to get back to 2 psi, and the cycle continues till tstat is satisfied.

Curious to know if I will get the same results if I add a main to my system and replace the valves on the radiators.

Fred

The build up of Pressure, in the system is the result of an over-sized boiler. The main venting will save you fuel by easily pushing air out of the main and not spending the first half of the heating cycle just getting air out. Saving time on getting air out means you will also have a shorter heating cycle to satisfy the thermostat and that should save on the number of short cycles you have before the thermostat is satisfied.
Have you ever measured your total radiator EDR and compared it to the Sq. Ft. of steam on the boiler plate? That will tell you how much your boiler is over-sized. In any case, I hope you are not using any temperature set-backs at night or when you are not home. That just makes the boiler run even longer to bring the house back up to temp and make the short cycles even more numerous.

Ying

Plate on boiler says 450 sq ft. Remembering back to the original radiators, it was petty close at about 430ish.

Unfortunatly, did not know a quarter of the things I knew about steam heating compare to now when I did the renovation, don't think the contractor at that time is knowledge about steam either. We propose taking out 2 radiators in 2 rooms and convert them to built in closets to connected rooms and storage for whatever space is left, thinking that there was no need for heat there, the radiators were removed without any input by the contractor.

And after that we also have to replace 2 radiator after replacing the shut off valve did not stop the leaks from the connections.

Adding to the nightmare, tenant on the second floor has parents that like sleeping in colder conditions, about 55F, so they have told me one time that the shut off valve to that radiator is completly off for that room.

So estimating based on what I know at this moment, EDR is less than 300 sq ft compared to the 450 boiler.

As for the set back, 2 degree difference, between the 4 periods. 71 awake, 69 work, 71 return and 69 sleep. You think I should just keep it all at about 70?

Fred

Once the Pressuretrol is replaced and most likely many of the vents, When you replaced those two radiator valves, did you also replace the matching spuds that came with them? If not, you need to have that done. There is no need to replace the radiators unless you know they have a rust hole in them. The spuds that came with the valves must be installed or they will leak, regardless of replacing the radiators.
If you also know you need to add two radiators back in, I would do that as soon as you can.
Once you do that, the tenant upstairs may be able to leave that radiator shut off with minimal short cycling.
Until all of these things are done, I wouldn't use any set-backs. Even two degrees will cause longer heating cycles, in the morning and in the afternoon and that will cause more short cycling on those cycles.

Ying

Yeah, they wont come out. Using s spud wrench broke the 2 things in the spud that held the wrench. I think the guy that was there to replace the shutoff cut too deep when he tried to cut the old spud out. So threads will not seal tight, ended up having to replace the whole radiator.

Putting the radiator back might not be that simple. Floor plans has changed and there might not be room for a radiator where the old pipes got capped off. Might have to redo the whole system when this boiler fails. As it was pointed out to me that my pipes might be piped wrong too.

For now, change the pressuretrol and put in a main and see how long it will last me.

Big thanks to all that commented

Fred

@Ying , watch the video towards the bottom of this thread that @Ironman posted:
https://forum.heatinghelp.com/discussion/168770/threading-a-damage-pipe-in-place-with-the-harbor-freight-ratcheting-pipe-threader#latest

Ying

Replaced the pressuretrol with the new one today. Works great with the settings and gauge reading.

curious though, people on this site always recommend cut in psi of .2 or .5. why not set the cut in at 0 psi? This is doable on the subtractive pressuretrols right.

JUGHNE

I believe the intent is not to drop to zero which might allow air back into the system. Not all air vents would necessarily be closed and the system could go into a vacuum sucking air back in.
The next pressure controlled cycle would then have to vent all air again.

You would not want this to happen until the T-stat was satisfied and the system off for a length of time for the air vents to cool off to open.

Jamie Hall

The reason for not going to 0 is that if the system doesn't quite drop to whatever the pressuretrol thinks of as zero, it won't reset -- and you won't get heat. Tiresome.