Which is Wrong in New Boiler--Pressuretrol or Pressure Gauge?

Captain Who

Maybe the pressure gauge is located below the waterline at first until enough water gets up into the system, thus lowering the waterline in the boiler? Would this explain why the gauge does not read any steam pressure during the first burns of the day? Or maybe it is just sticking and needs to be excercised a little each morning to get it unstuck?

Larry in Elkins Park_4

Hello all--I have an issue wih my new steamer that we can't seem to pinpoint.
New Crown 207BTU installed last month. Piping is correct, in fact, making use of basement height it is 34" from NWL to the header. Boiler size is correct for my EDR, I was able to confirm the measurements. Radiators through the house have primarily new vents, and system is balanced by valve sizes. Also found and fixed 6 leaks on several radiators involving their shut-off valves.

Here's the issue: System is controlled by factory-installed CycleGard 400, wired for the intermittent test (every 20 minutes on this model), and factory-installed L404F pressuretrol.
During the first 60 minutes of operation, or 3 cycles, no pressure registers on the pressure gauge (I've a 3 story house, and although only 1 main, and thus 1 long loop, lots of piping.) After that time, the system starts to build pressure.
And here's where we (me, and the contractor) are confused. Once pressure starts showing, it will get up to 5 psi on the gauge before the pressuretrol kicks it off. The pressuretrol is set at under 2, with subtractive around 1 1/4. As I said, the pressuretrol was preinstalled on the factory pigtail. The pressure gauge was preinstalled by the factory directly into the side of the boiler, a few inches lower than where the pigtail comes out, above the CG400. The system has been well cleaned, including removing and cleaning the pigtail.
So which one is correct? Is there a reason for the pressure gauge in this installation to read higher than the pressuretrol, but this to be okay in operation? Can one of these be wrong?
For what it's worth, on the boiler that was replaced, the gauge was top-mounted to where the riser should have been leaving, and it never registered any pressure, with the older Honeywell dial additive pressuretrol working fine. That installation, from 1979, was probably not even correct as it was a larger boiler (225BTU) with only one riser, out the side and then up to a very short header.
On last cleaning, contractor pulled and cleaned the pressure gauge and felt that it may be affected by crud bits that caught on it and are causing it to read high once it starts getting pressure.
Should I just trust the pressuretrol and not worry? Is it worth asking for a second pressure gauge to be installed on a tee alongside the pressuretrol?

Unknown

I'd change the gauge first

I've seen them crap out in less than a few months when mounted directly into the boiler . Best thing to do is pull the old one out , thread in a pigtail to protect the gauge , and install a new one that reads to 30 psi . You can even add another gauge next to that one that reads to a lesser number . Which might be more accurate than the 30 psi .

bklynick

similar issue

Larry,

I have a very similar issue, check out this thread:
http://forums.invision.net/Index.cfm?CFApp=2&Message_ID=370039

In summary:
* check for clogged pigtail
* check for clogged pressure gauge
* don't trust the pressure gauge
* cracked pressuretrol switch assembly (fails at 5psi)

Since the boiler has been heating fine, and it's the middle of the heating season, I really don't want to fiddle with it now.

In the spring I plan on installing brass pigtail w/ a vaporstat and 5psi pressure gauge.

nicholas bonham-carter

accurate gauge

where can one buy a really accurate gauge for our low pressure one pipe systems-say up to five pounds??

Jon Held

http://www.gaugestore.com/prodinfo.asp?number=33041

Captain Who

This company specifically says that their gauges are for heating applications: http://www.wal-rich.com/Online_Catalog/gauges.pdf. Although the pigtail definitely protects the gauge from high temps., it might be better to buy one of theirs. I haven't been able to find a max. temp. specification from them yet, though. They specifically state, however, that their low pressure "diaphragm" gauges will definitely be damaged by overpressure, so we need to take that into consideration.

Larry in Elkins Park_4

Update as requested

I have not yet added a new gauge via a tee, my people are not coming in until this week, it was too cold and windy for them to do the additional chimney lining.

However, I've done some additional work. I had to clean the boiler Wednesday, it was suddenly filthy. I took that opportunity to clean the pigtail again, and again yesterday. I also removed the pressure gauge yesterday and cleaned it. I noted that the pressure now maxed at under 4 psi. Last night, I cleaned it again, following some advice posted recently. This time I got a pin into the little hole at the base, and also shook crud out through there into my hand. I checked today, and was pleasantly surprised to see that the pressuretrol shut-off was at 2.6 psi (plus whatever it lost by the tiome I ran down to see it). The cut-out on this 'trol was set at just under 2 psi.
So I am more convinced that the system is operating correctly - but will still have an additional and better gauge mounted on a tee with the 'trol.

I can't understand why the boiler manufacturer does not do this in the first place instead of mounting the crappy gauge directly into the boiler. Given the overall costs involved in a boiler purchase this addition is not a significant increase. They can at least put the 30 psi gauge on the pigtail--or on its own pigtail.

Larry in Elkins Park_4

Pressuretrol is accurate

Pressuretrol and a smaller pressure gauge now on the pigtail via a tee.
And the pressuretrol is shutting the system in synch with the smaller gauge--just about 2 psi on it, and at a similar mark on the 'trol. The 0-30 psi gauge on the boiler reads just about 3 now. I've adjusted to have it kick back on at .5, adn this is what the 'trol shows.
So I am now satisfied wiht the operation.

Sure wish some day I can have a team to post "Go __! for.

Peter Zelchenko_2

I have a PA404A Pressuretrol (additive) on a similar arrangement, a 3-floor building but we have 16 radiators and a 700 sq. ft./hr. boiler. It's -2 degrees out. I found the Pressuretrol set way too high: the gauge had been reading about 6 psi. A vent in the basement was dripping. I took it down about 3 full turns and it is hard to read the mark on it so I don't know what it is at now, but the flame did cut out.

The problem is that, okay, let's say the pressure limit is now at a more reasonable level for this system (let's say an absolute maximum of 4 psi). Now the building is going to be too cold. Why do I need that much pressure to heat up this building?

Larry in Elkins Park_4

You Dont'

Need that much pressure--you need it to cut at 2lbs--it should actually run less.
If this was running that high, it may nave damaged vents..
Remove the 'trol and make sure the opening from the pigtail is clear--when my T was added, the plumber sloppily left some wisps of teflon tape across the opening, and this affected the 'trol's ability to sense the correct pressure, it ran too high. Also check the pigtial, water level, etc.