Pressuretrol Question/ Water level question

nate70500

Should the pressuretrol trip and shut off my boiler on a regular cycle? Or is it more of a safety device that shouldn't really trip ever? I notice that when I get home from work and turn my heat back up from 62 to 68 that the pressuretrol will trip a few times before the thermostat hits the desired temperature. But when its already set at 68 and is just maintaining the temperature in the house it doesn't trip during those cycles. A service tech from the gas company told me that it should not be tripping and that it means there is an issue in my system (he was here to replace the gas meter, not work on the boiler so I don't know if he actually knows anything about steam boilers). I was under the impression that the way it is functioning is normal but want to make sure I don't have an issue.

The other question is during the heating cycle should the water level on my sight glass drop? It drops from 1/2 full to about 1/3 full. It does not trip the LWCO though. From what I know it would make sense for it to drop since the water is being converted to steam and rising into the pipes. When the system cools down the water level goes back to 1/2 full in the sight glass.

nate70500

Pressuretrol is set at 0.5 psi cut in 1.5 psi cut out

ethicalpaul

Ideally the pressuretol shouldn’t have to trip during a heating cycle but some things can make it do so:

- your setback is too large for steam. Set it back 3 degrees only and see if things are better
- do you have good main venting?
- an oversized boiler will produce more steam than your radiators can condense, causing cycling on pressure

Your settings are good. Don’t raise them. It is a safety control ideally.

Your water drop sounds large to me. Your boiler could be throwing water into the main. Have you already submitted photos of your boiler piping for all of us to criticize? 😉

nate70500

ethicalpaul said:

Ideally the pressuretol shouldn’t have to trip during a heating cycle but some things can make it do so:



- your setback is too large for steam. Set it back 3 degrees only and see if things are better

- do you have good main venting?

- an oversized boiler will produce more steam than your radiators can condense, causing cycling on pressure



Your settings are good. Don’t raise them. It is a safety control ideally.



Your water drop sounds large to me. Your boiler could be throwing water into the main. Have you already submitted photos of your boiler piping for all of us to criticize? 😉

Ok I'll try changing the setback. And yes I have had you guys look at my near boiler piping and it is done correctly. If that doesn't help Ill check out the vents on the main, I've never replaced them as they've always worked but maybe they stopped working.

neilc

you show your pressure is set low,
but does your gage agree ?
is the gage on the same pigtail ?

nate70500

neilc said:

you show your pressure is set low,
but does your gage agree ?
is the gage on the same pigtail ?

Yes the gauge agrees (It is a brand new gauge installed less than a week ago). It is not on the same pigtail as my pressuretrol, it is on the side of the boiler.

nate70500

> @ethicalpaul said:
> Ideally the pressuretol shouldn’t have to trip during a heating cycle but some things can make it do so:
>
> - your setback is too large for steam. Set it back 3 degrees only and see if things are better
> - do you have good main venting?
> - an oversized boiler will produce more steam than your radiators can condense, causing cycling on pressure
>
> Your settings are good. Don’t raise them. It is a safety control ideally.
>
> Your water drop sounds large to me. Your boiler could be throwing water into the main. Have you already submitted photos of your boiler piping for all of us to criticize? 😉

So I changed the setback to only 3 degrees and tried that today. I set it at 65 degrees and then turned it back up to 68 a few hours later. The pressuretrol tripped one time after the boiler running for 20-25 mins but the house was just about at 68. When the boiler came back on it only ran for about 2 minutes and that was it. Seems like changing the setback helped. But tomorrow I will be picking up a replacement steam vent for my main and see if that further helps. That is the only one I have not replaced in the house so likely it is contributing to the problem. Thank you for your help!

Fred

If you measure your radiators, you will find that the boiler Sq. Ft. of steam output (on the boiler plate) is greater than the total of the radiator EDR. Probably significantly greater. That's not unusual, although not ideal. When it comes time to replace the boiler, install one as close to the radiator EDR as possible. The reason for the short cycling is because the boiler is producing more steam than the system and radiators can condense. When that happens, pressure builds and the Pressuretrol is doing its job by shutting the boiler down until the pressure drops to .5 PSI and then letting the boiler run again until it either satisfies the Thermostat or the pressure builds to the 1.5 PSI Cut-out pressure. Your system is working as it should. The gas guy doesn't know much about steam heat or he would have explained that to you.
As far as the water dropping, has the boiler ever been skimmed? Skimming is different than draining and refilling. There should be a skim port, above the water line. The goal of skimming is to remove any oils that are on the surface of the water. If there are oils on the water, it makes it difficult for the steam bubbles to break through the surface of the water and that will cause some water to push out into the wet returns. Try a good long, slow skim and see if that stabilizes the water in the sight glass. Normal bounce in the sight glass should be about half to 3/4 of an inch during the heating cycle.

ethicalpaul

You're very welcome. If you really like the big setback, you can maybe come back to daytime temperature in stages if you have a good enough programmable thermostat. Like 3 degrees for an hour, then another 3 degrees the next hour.

Fred has good advice about the carryover from oils requiring skimming.

I look forward to your main vent investigation.

You could also clock your gas meter to see if the boiler is overfired at all. Making sure it's not getting too much gas pressure at the manifold can possibly help an oversized situation. If your steam pro can measure the pressure and check the CO levels, they can make sure it's as low as it safely can be.

EBEBRATT-Ed

You system both the pressure control and the water level sounds completely normal to me.

The fact that the pressure control does not trip during a normal (non setback) cycle and that the water level returns to normal after the boiler shuts down mean everything is ok

nate70500

ethicalpaul said:

You're very welcome. If you really like the big setback, you can maybe come back to daytime temperature in stages if you have a good enough programmable thermostat. Like 3 degrees for an hour, then another 3 degrees the next hour.

Fred has good advice about the carryover from oils requiring skimming.

I look forward to your main vent investigation.

You could also clock your gas meter to see if the boiler is overfired at all. Making sure it's not getting too much gas pressure at the manifold can possibly help an oversized situation. If your steam pro can measure the pressure and check the CO levels, they can make sure it's as low as it safely can be.

Currently have a manual thermostat lol...going to be buying a programmable one soon. The wiring to it the thermostat needs to be replaced just waiting for my electrician friend to come do it

ethicalpaul

Even better! Manually bump it back up in stages 😀

Or don’t sweat the cycling. It’s not really cycling if it gets nearly to temp on a reasonable setback

Is your setback for comfort or because you think it will save you wads of cash? If the latter, then it won’t and you should set it and forget it

nate70500

buyin

ethicalpaul said:

Even better! Manually bump it back up in stages 😀



Or don’t sweat the cycling. It’s not really cycling if it gets nearly to temp on a reasonable setback



Is your setback for comfort or because you think it will save you wads of cash? If the latter, then it won’t and you should set it and forget it

Its for a little of both. And I'll try bumping it back up in stages and see if that helps at all

nate70500

Fred said:

If you measure your radiators, you will find that the boiler Sq. Ft. of steam output (on the boiler plate) is greater than the total of the radiator EDR. Probably significantly greater. That's not unusual, although not ideal. When it comes time to replace the boiler, install one as close to the radiator EDR as possible. The reason for the short cycling is because the boiler is producing more steam than the system and radiators can condense. When that happens, pressure builds and the Pressuretrol is doing its job by shutting the boiler down until the pressure drops to .5 PSI and then letting the boiler run again until it either satisfies the Thermostat or the pressure builds to the 1.5 PSI Cut-out pressure. Your system is working as it should. The gas guy doesn't know much about steam heat or he would have explained that to you.
As far as the water dropping, has the boiler ever been skimmed? Skimming is different than draining and refilling. There should be a skim port, above the water line. The goal of skimming is to remove any oils that are on the surface of the water. If there are oils on the water, it makes it difficult for the steam bubbles to break through the surface of the water and that will cause some water to push out into the wet returns. Try a good long, slow skim and see if that stabilizes the water in the sight glass. Normal bounce in the sight glass should be about half to 3/4 of an inch during the heating cycle.

The boiler was flushed and skimmed about a month ago (by a steam pro). He skimmed it for almost 7 hours after he did some repairs to the piping. The bounce in the sight glass is only 1/4 in during the cycle. But since changing the setback to less, the water doesn't drop down throughout the cycle then fill back up as the system cools down.