Pressuretrol wiring?

nowhere182

Hi everyone, and thanks for the help that you all provide. I've learned so much here, and now have another question. I have a steam boiler, and last weekend, it got to around 4 pcs internal siphon. I removed the pressuretrol, and replaced the pigtail. Here's the thing - I may have reverse wired the pressuretrol back. Is this possible? It's a Honeywell P404A 1009. I don't think I did, but what can happen if it's backwards? Since I've changed the pigtail, the pressure is still high. Any ideas? Thanks so much in advance!

Fred

No, you can't wire it backwards. Make sure the tiny orifice inside the hex base that screws onto the pigtail isn't clogged. If it still runs high, you can re-calibrate the Pressuretrol by following this procedure:
Inside the Pressuretrol, right below the micro switch, there is a pivot arm. At the end of that arm you will see a screw pin that is activated by the diaphragm at the bottom of the Pressuretrol. If you look very carefully at that screw pin, you will see it actually has a tiny (I mean tiny) hex head on it. It takes a .050 hex wrench and you can turn it clockwise (Towards the bottom of the Pressuretrol to decrease the Cut-out pressure or counter clockwise to increase the cut-out pressure (which none of us want to do but who knows, your Pressuretrol may be really screwed up!). Turn the power to the unit off first. You may find the first attempt to turn that screw a little bit stubborn (relatively speaking) because it has some Locktite on it but it does turn. Don't turn too much, a fraction of a turn goes a long way towards getting it adjusted where you want it (maybe 1/32 inch turn to start with). You may need to play with it to get it exactly where you want cut out to be.

neilc

take a quick picture of the wires landing on your pressuretrol,
some of them have a third screw terminal there,
if yours does, are you landed on common and normally closed ?

EBEBRATT-Ed

can't wire a PA404A backwards as long as it was correctly wired to start with

neilc

EBEBRATT-Ed said:

can't wire a PA404A backwards as long as it was correctly wired to start with

yup,
agreed,
missed the model # on the first read thru,

mpkozar

Not trying to hijack this thread, but I calibrated my pressuretrol this weekend according to the above procedure. Adjusted cut-out pressure to 1.5 psi and with the differential set at 1, it doesn't cut back in until the pressure drops to 0 psi. It's only off by 0.5 psi, but is that the best I can expect or is there a way to adjust the differential?

Fred

@mpkozar Did you or someone else ever bend the indicator on the Cut-in scale or stretch the spring trying to adjust the Pressuretrol? Typically, following the procedure above for the set Cut-Out (White wheel setting + Differential) will not affect the Cut-In. I would say first make sure the link behind the Cut-In scale has not come loose and then set the Cut-in indicator where it needs to be to give you the Cut-in you want, ignoring the actual scale. There really isn't anything wrong with a 0 PSI Cut-in if the Pressuretrol consistently operates.

mpkozar

@Fred I didn't and I doubt that anyone has before me. The pressure drops from 1.5 psi to 0 in about a minute or two so I think you're right and I'll just leave the cut in at 0 psi.

Thanks, this forum is extremely responsive and helpful!

StevenSchunk

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