Pressuretrol PA404A Wiring

Boiler Talk

After one year I'm very much a newbie, but my 5 PSI gauge recorded 4 pounds of pressure.  Can it be the wiring is backward?  The Diagram for the 404A shows the top connector being the hot one.  I'm not sure I understand the following diagram. 



<a href="http://www.heatinghelp.com/files/posts/15976/Honeywell%20404A%20Pressuretrol.pdf">http://www.heatinghelp.com/files/posts/15976/Honeywell%20404A%20Pressuretrol.pdf</a>



I run on oil and have a Beckett AF/AFG burner and a Cyclegard CG450 LWCO.



It's hard to follow the wires. It appears the wire on the top contact goes to the LWCO contact P2, which is for Limit Controls.  I guess this from the Cyclegard wiring diagram.



The wire on the lower contact goes to the burner control (7505) Limit contact, which I guess is the burner circuit.  I also guess there is a jumper at this point, because the connection is offset a bit from the other contacts. 



So does it make any difference if the wiring is reversed? 



 

BobC

Blockage?

It's just a switch so the wiring is not at fault, did this just start showing to much pressure?



Check the base of the pressuretrol and make sure the little hole at the base of that brass fitting is clear. Something is probably blocking the pressuretrol from being able to see the boilers pressure.



if you move that silver lever under the switch you should be able to shut the boiler down. If you can't the switch may have failed shut.



Bob

Boiler Talk

Reply to Blockage

No, I noticed a high reading a few months ago.  The cutout is 1.  I'll have to remove the pressuretrol tomorrow and look.  Also, I'll try to move slightly the lever on the right side of the unit.  I hope it's just a blockage.  Can you get parts for this thing if the switch is bad? 

BobC

Rocker

The silver piston below the switch is acting on the silver rocker and as pressure increases that piston moves and will actuate the switch. Your picture looks like the piston is extended and i would expect that switch to be off when it's like that. Actually it only takes a little movement so you probably can't tell by eye.



Is that piston's position different when there is no pressure in the boiler? The white wheel should be set to one.



Before doing the test below try moving that rocker switch when the circuit breaker is off, you should here it click as you move the rocker up and down - it only takes a little movement to actuate that switch.



If moving that silver rocker does not shut the boiler down, shut off the circuit breaker that feeds the boiler and remove one wire from the switch and then turn the circuit breaker back on. The boiler should not start even if the thermostat is calling for heat. be careful because those wires carry 120 volts don't touch them when the circuit breaker is on.



Bob

Boiler Talk

Misaligned spring. Probably.

I moved the rocker while the boiler was running and it shut off.   But I found movement rather difficult.  I turned the wheel to a higher number and of course the movement was even more difficult.   Why was it so hard to move?  I removed the Pressuretrol and saw the spring connected to the other side of the rocker wasn't set properly.  I push the spring to where I think it needed to be and found movement of the rocker much easier.  Nevertheless, I took the pressuretrol further apart to examine everything.  I think the spring was the problem. 



In fact you can see the bottom of the spring in the first picture.  It was not set. 

BobC

Good news!

That makes sense,  hopefully everything will work normally now.



Bob