My Low Pressure Gauge Readings

Unknown

What is the boiler water line doing? Is it jumping up and down? Can you look in the glass tube to see? Do you have pictures of the near boiler piping? Are the mains insulated? This looks like a continuation of another post.

Kool Rod

What to Conclude

Here is what I learned after installing the gauge yesterday. During the remainder of the day, when the boiler turned on to maintain the 68 degree t-stat setting, not much happened. The boiler ran for a short time, and the needle jiggled, but did not move enough to get a reading. During these short run times, the valves were silent.

The setback was set down to 65 degrees, and the boiler turned on once that I know, at about 5:00 a.m. or so. I don't know how long it ran, but we can assume that the t-stat was reading 65 degrees at 6:30 a.m. when the boiler cycled on to recover from the setback. The recovery temp was 70 degrees, the usual setting for the t-stat this heating season.

Here is what I noticed. The boiler had been on for about 30 mins before the air valve started to hiss. The radiator had been getting hot during this time, although it was not all-the-way hot. Over the course of the next 30 mins or so, until the t-stat was satisfied, the gauge basically showed that the pressure would rise and drop and rise and drop. When the pressure dropped, the valve would become silent, and stay silent as the pressure dropped below zero, at which point it started to rise. When the pressure rose to one half ounce, the valve started hissing.

During these pressure swings, the pressure got at a little bit higher each time, until it topped out at 6 ozs, which it reached two times at least, and maybe a third. I did not hear a swooshing, sucking sound as the pressure dropped during these little cycles. That sound did not occur until the boiler turned off, presumably because the t-stat had been satisifed.

So what does that tell me about my hissing and the performance of the system as a whole?

Timco

You will never know what is really going on until a pro tests the combustion gasses, gas (manifold) pressure, and clocks the meter to see what the unit is really firing at. (for natural gas) You could be under-fired and never know it, or you could be all sooted up. Vents hissing when pressure is being read is good, but it should not drop during a heat call. It should build pressure until vap stat or presstrol cuts off on pressure, and then t-stat will stop all action when satisfied. The more rads that get hot and vents close, the faster boiler should make desired pressure and cycle off on pressure. Half hot rads are not satisfied fully for one reason or another.

Tim

Kool Rod

The rad . . .

eventually did get fully hot, so it is not like the rad stayed half cold throughout the entire cycle. The last time I checked, the water line is pretty stable when the boiler fires, and the water inside is clean.

Timco

eventually? Sounds like it firing for a looooong time before everything gets steam. Clock the meter, check for soot or rust in bottom.

Tim

Kool Rod

Probably Should Have Said . . .

This is a four unit apt bldg. I'm on the second floor, and steam hits the rad that feeds the riser about 10-11 mins after boiler fires from cold start. Riser is vented w/two Gorton 1s, and rad is vented w/Gorton 5 valve.

Timco

I get steam to the farthest unit on the 3rd floor of a 40 unit building in that amount of time...at 1lb steam. That is from a 'warm' start, on a call for heat with a 'warm' boiler and cold rads. Boiler is likely oversized in this scenario and I never did a heatloss because the boiler is there and working...not my install.

Tim

Kool Rod

This Morning

My bldg is four stories tall, and I've got about 23 rads to heat. The main is about 50 feet long, and steam hits the farthest riser, in the corner of my bedroom, about 13 mins after a cold start. It then must travel one more story before it hits the end of the line. Needless to say, on a warm boiler, steam hits the rads and that riser faster.

My main setting on my vaportat is set inbetween 1 and .5 psi; it is not delineated into ounces, unfortunately. I've tried to set it for 12oz cut out.

This morning, t-stat for 70 degree was satisfied in about 55 minutes. Pressure got to about 6oz, maybe a litle bit above, two times, falling to below zero each time. After the second, it rose to 3ozs before the boiler turned off when the t-stat was satisfied. This time, there was less hissing. The valve started hissing around 1 ounce of pressure, and the valve was silent during times when the pressure was rising. So there was no correlation this time between hissing and when the pressure would rise and drop, like there was last time.