Steam boiler gauge correct? Seeking advice to optimize performance and eradicate water hammer

ChrisF

I am in the process of trying to get my steam boiler to run efficiently and properly. The main issues I've been having is some banging noise (water hammer), in a few radiators. Someone here advised to check the pressure of the boiler, so I'm trying to do a few things to get that squared away. I had a skimming tap installed recently, and have been skimming the boiler every week. I took the pigtail off, and noticed it was clogged up, so I cleaned it out, put it back. I installed two new Gorton #1 main vents, and I also replaced the pressuretrol for a brand new one. After doing all that, I am still getting a high psi reading of around 12 pounds (see photo) on the boiler gauge. I've been reading that the 0-30 psi gauge on the boiler is not the greatest in terms of accuracy, and I should add another one, possibly off the pigtail. If that is the case, should I run a 'T' off the pigtail before the pressuretrol? The two radiators farthest from the boiler are making banging noise when the boiler is firing up. Everything heats up well, I'm just trying to resolve the water hammer and make sure that everything is running as it should.

ethicalpaul

I have a concern that your pressuretrol isn’t wired correctly into your other control wiring.

You might:
- Power down the boiler
- Disconnect either one of the ptrol wires, leave it hanging in the air
- power up the boiler
- turn up the thermostat to make it ask for heat

The boiler shouldn’t fire up. If it does, then the boiler is ignoring the ptrol

ethicalpaul

Also, does that gauge rise from zero during the heat cycle to that point? Does it go higher?

The piping looks OK but with it being a Dunkirk, we all wish they had piped both steam supply ports.

Chris_L

I doubt you are operating at 12 psi. If you were, you'd hear your radiator vents screaming well before then.

You can easily check the accuracy of your pressure gauge. Is that a nipple and valve (with the yellow handle) attached to your sight glass? If so, put a hose barb into the bottom of the valve and attach some clear vinyl tubing. Run the tubing up to the floor joists above, and leave the top end open. Then fire up the boiler and open the valve the tubing is attached to.

The difference between the height of the water in the tubing and in the sight glass indicates the pressure in the boiler (28" = 1 psi). See how high the water goes in the tubing before the boiler shuts off on pressure. Shouldn't be more than 60" if you have your Pressuretrol turned down all the way (and it is working).

But be careful. If the water in the tubing starts rising too much you'll have to turn the boiler off or get hot shower of boiler water.

JUGHNE

Do Paul's remove the wire test.

Correct wiring if needed.

Add tee-nipple-90-coupling-0-3 PSI gauge above your pigtail.
Use brass or stainless steel 1/4" fittings.

Do the tubing test at your own risk...tubing gets pretty soft at 200+ degrees.

Ying

0-30 gauge is not that accurate, but usually not off by that much, if they still work. That is that it will start at 0 on cold start and takes a while to build up any pressure and then slowly goes up.

Get another guage on the pigtail. It is a very easy job, took me less than 10 minutes to put everything in and it was my first time doing it for my boiler.

ChrisF

Thank you. I'll have to do the wire test mentioned above, and see what happens. When the boiler fires up from cold, the gauge starts at zero. The funny thing is, it takes a long time for the needle to drop back down to zero, when the heat is off. There could be no more steam pressure left in the system, but it will read 5 pounds, and gradually decrease.

ethicalpaul

I think that would point to a clogged pigtail or gunked up ptrol, but I know you said you fixed both of those possibilities, so it's a puzzler to me.

Chris_L

When the boiler fires up from cold, the gauge starts at zero. The funny thing is, it takes a long time for the needle to drop back down to zero, when the heat is off.

This tells you the gauge is not working properly. When the boiler is shut off, the gauge should return to zero (or less if it can read vacuum) within a matter of seconds.

Fred

How much water do you have in that boiler? It looks pretty full. Those side tap boilers should not be more than half, maybe 2/3's full (if both sides are used. With just one side in use, water in the boiler will tend to push to that side so I'd keep it at about half full..

Jamie Hall

Chris_L said:

When the boiler fires up from cold, the gauge starts at zero. The funny thing is, it takes a long time for the needle to drop back down to zero, when the heat is off.

This tells you the gauge is not working properly. When the boiler is shut off, the gauge should return to zero (or less if it can read vacuum) within a matter of seconds.

Define "long time". As sort of a rule of thumb, a moderately large system can be expected to drop around a pound to a pound and a half a minute -- but not seconds. But it's quite variable.

ChrisF

So I tried the wire test suggested earlier by Paul, and disconnected one wire from the pressuretrol, and tried to run heat, but the boiler wouldn't kick on, so that eliminates a bad pressuretrol or it not being wired correctly.

I haven't monitored the gauge for longer than a few minutes, but it definitely doesn't drop to zero that quick....maybe takes half an hour or even more. Seems like my gauge isn't working properly.

Do you think there is too much water in the boiler? Currently the water level is a little below half on the sight glass. I do get two or three radiator vents spitting water on the radiators in the rooms furthest from the boiler.

Chris_L

@ChrisF, have you seen this video?
https://heatinghelp.com/systems-help-center/wet-steam/
Isn't that the same boiler (possibly rebadged) as yours, with the steam coming out of the side not far above the water line?

Try what @Fred says, maybe even a lower water level, and see what happens with your banging.

@Jamie Hall I don't think we disagree. When I said the pressure should go down in seconds, I wasn't thinking single digits. If the boiler is running at less than 2 psi, I'd say 90 seconds is seconds not minutes. (Mine goes down to zero much faster, but I never exceed 1/4 psi).

ChrisF

@Chris_L , Wow! That is a lot of wet steam being produced!! I'm wondering if I have the same problem? However, if I drain some water out of the boiler, it won't want to fire up, and the (low water) red light comes on, on the low water cut off. The boiler will come on, only

after I add more water.

@ethicalpaul I saw your wet steam video. Hoping I don't have that same kind of issue.

Fred

@ChrisF , yes, when I looked through you first set of pictures, I thought the LWCO seemed to be sitting pretty high on the boiler. 'M wondering if the probe is in the right boiler tapping? Check your Owner's/Installation manual.

Jamie Hall

@Chris_L -- yes, 90 seconds sounds reasonable. Cedric drops from 7 ounces to 2 ounces in the length of time the burner goes through its post purge... which is about 30 seconds.

ethicalpaul

@ethicalpaul I saw your wet steam video. Hoping I don't have that same kind of issue.

It's not actually too horrible of a situation, and probably fixable for not much cost or effort if you do. Your piping is way better than mine and I have mine a lot better now. Even when mine was throwing all that water into the main, I had no spitting vents, nor any other noticeable problem, due to good main venting which you should also check into if you haven't. Contrary to popular belief, steam heat is VERY forgiving and it usually takes several bad things stacked up to result in poor performance.

So I tried the wire test suggested earlier by Paul, and disconnected one wire from the pressuretrol, and tried to run heat, but the boiler wouldn't kick on, so that eliminates a bad pressuretrol or it not being wired correctly.

It does look good for the wiring, that's great! But the only full test for the ptrol is to get your pressure high enough to trigger it. It may still not be activating on pressure, but it being a new one I think the odds of that are slim. A new gauge should help you get to the truth. You're going to get a 0-3psi one I hope, to test with at least temporarily, then code dictates you have to have a 0-30 one on there. You can mount both if you feel like it.