How do you test Pressuretrol

acl10

I have a Honywell Pressuretroll

loks like this one

<a href="http://www.amazon.com/Honeywell-PA404A1033-Pressuretrol-circuit-pressure/dp/B0006UPPMM">http://www.amazon.com/Honeywell-PA404A1033-Pressuretrol-circuit-pressure/dp/B0006UPPMM</a>



How do I test it to see if it works.

Does this pressuretroll have a mercury switch?

acl10

Also the pigtail comes out of the 67 is that correct?

Also the pigtail comes out of the top of the MM 67 LWCO is that correct?

TomM

need gauge

Its a switch that 'makes' at your setpoint, and 'breaks' at your setpoint plus 1.5 psi.

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you would need an oz/sq ft pressure gauge, in-line with the pressuretrol, to see if it was working correctly.  That way, you would not have to use a voltmeter to see if it was working correctly.  You should have a low pressure gauge anyway.  Those factory gauges are crap.  Mine reads 20 psi when the boiler is off!

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TomM

diaphram

no, the switch is actuated by a diaphram and lever that makes or breaks the switch.

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if you have the pa404a1025, i think that one is subtractive, not additive as the pa404a1033 is.  the 1025 would break at your setpoint, and make at your setpoint minus 1.5psi.  Not 100% sure if the 1025 is subtractive though, but you get the idea.

BobC

Pressuretrol test

In the picture that shows the inside of the pressuretrol, the brown object is a microswitch. The two brass screws are the contacts of that switch, Normally the contacts of this switch are closed until pressure builds enough to trip it off. With the boiler power switched off at the circuit breaker panel, you should measure zero ohms across those two brass screws. You can force that silver arm up and down (1/16 to 1/8") to mimic the action of the internal bellows, when you do you will hear a small click and the reading should go up to many thousands of ohms. Move it the opposite way and the reading should go back to zero ohms.



All that does is tell you that the switch works it does not tell you if the pressure bellows is good or if the pigtail is clear.



With the power back on you can manipulate the silver lever and should be able to turn the burner off and on, assuming the thermostat is calling for heat. Just be careful so you don't get a shock, those screws are carrying 120v.



Bob

acl10

Why should it face the opposite way from the pigtail?

Why should it face the opposite way from the pigtail? I changed it from the picture but I would like to know why as it says in Heating Help book

Charlie from wmass

The direction matters less now.

The older(better models) used a vial with mercury in it so the pressuretrol needed to be level to work accurately. With the old style as the pigtail expanded and contracted if it was install as yours is the pressuretrol would be tilted off level.

jpf321

not important unless mercury...

the book should also say that pigtail try to straighten out when heated .. if you have a mercury p-trol and the pigtail tries to "straighten out" left to right... you will have a false trip due to the mercury floating left or right .. the would be solved by changing orientation to a front/back movement instead .. however, as I said, this only matters if you have mercury switch .. otherwise, makes no difference at all. 

crash2009

I winged it

Looks like I did it the hard way

crash2009

Charlie

If a guy wanted to,,,Could you mount the p-trol on the wall of the boiler room and run the wires and some copper tubing from the pigtail up to it? 

acl10

Is it on right connected to the LWCO 67?

Is it on right connected to the LWCO 67?