PA404A PressureTrol Cut-in inconsistent

parity_check21

It's our first winter in the house, getting accustomed to this gas fired steam boiler.

Sometimes the heat does not kick on right away, it might hours after a heating call is being made. I noticed if I nudge the cut
-in gauge slightly, the system clicks on and energizes the boiler. That tells me maybe once the pressure drops under the cut-in, it is not closing the circuit.

I have a pair of these PA404A these pressuretrol boxes, one is set to approx .5 with diff 1. Second one is about 3. Im guessing the second one is protection in case the first one fails?

Anyway, I just raised the cut-in on the left to .75ish thinking it might help. Trying to avoid replacing the PA404A if it is not necessary.

Still learning about steam, Please educate me.

Thanks!

EBEBRATT-Ed

The PA404A is not the most accurate control. Just raise the cut in slightly

JUGHNE

Have the pigtail under the controls been cleaned?

EdTheHeaterMan

JUGHNE said:

Have the pigtail under the controls been cleaned?

The way your controls are installed, that is not an easy task.
1. Remove the wires from both controls
2. Remove both controls by spinning them off at the elbow
3. Remove the pipe nipples from the tee fitting
4a. If the pigtail trap can be removed then spin it out.
4b. if not, then remove the pressure gauge and tee
5. Remove pigtail trap and flush with water until it is clear. You may need a pipe cleaner or stiff but flexible wire to drive out any debris in the trap.
6. When pigtail trap is clear re-install with pipe sealer on the threads.
7. Charge the trap with a few tablespoons of water
8. Replace all the other parts in reverse order from 4 to 1 with pipe sealer on the threads.
This can be a real PIA, but if the trap is plugged with sludge, then no control or gauge connected thereto will be accurate.

Good luck.

EDIT. the teflon tape on the pipe and fittings indicate that this has been done at least once since the boiler was installed.
Also. there are missing gauge glass guards on the boiler. That glass can get hit and break.

Then you will have an emergency on your hands resulting from breaking glass. LOL https://www.supplyhouse.com/Weil-McLain-563-334-580-Water-Gauge-Glass-Guard. You need two.

HVACNUT

Agree with @JUGHNE. Clean the pigtail and the tapping in the block. Set it back to .5 or as low as you can get it without disconnecting the linkage. 

109A_5

Hello @parity_check21,
If you disassemble the pressuretrol wiring and piping you may want to replace the Brass Tee and the two elbows with Cross fittings and plugs for the unused tappings. That way cleaning and inspection can mostly be done without disassembling the pressuretrol's wiring and piping in the future. Then in the future the plugs only need to be removed. The outer coiled sheathing from a lawn mower throttle cable (or the like) can be used for a mini Snake through the pigtail and into the boiler to maintain the open path.

An example;
https://www.supplyhouse.com/Bluefin-BLX025-1-4-Black-Cross

"parity_check" I like it.

parity_check21

Thanks for the feedback. Raising the cut-in seemed to work. I will look into clearing the pigtail trap if the problem persists. The boiler drain was clogged and took a while to unjam it to flush out sentiment. The water was black and initially just trickled out. The people before me were not doing adequate maintenance.

I will buy some glass guards, makes sense to have them.

parity_check21

It's a few days later and the system is working fine with the slight increase in cut-in. Some of the radiators had to be tightened because that tiny bit of pressure increase, with the differential I'm just under 2psi.

@EdTheHeaterMan before starting the cleanout procedure, does the system need to be completely cooled off?

EdTheHeaterMan

parity_check21 said:

It's a few days later and the system is working fine with the slight increase in cut-in. Some of the radiators had to be tightened because that tiny bit of pressure increase, with the differential I'm just under 2psi.

@EdTheHeaterMan before starting the cleanout procedure, does the system need to be completely cooled off?

No. But you will probably burn your fingers if you try to do it when hot.

Disclaimer: CONTENTS OF STEAM BOILERS ARE HOT WHEN OPERATING.
So keep pressure controls away from sensitive body parts

parity_check21

EdTheHeaterMan said:

JUGHNE said:

Have the pigtail under the controls been cleaned?

The way your controls are installed, that is not an easy task.
1. Remove the wires from both controls
2. Remove both controls by spinning them off at the elbow
3. Remove the pipe nipples from the tee fitting
4a. If the pigtail trap can be removed then spin it out.
4b. if not, then remove the pressure gauge and tee
5. Remove pigtail trap and flush with water until it is clear. You may need a pipe cleaner or stiff but flexible wire to drive out any debris in the trap.
6. When pigtail trap is clear re-install with pipe sealer on the threads.
7. Charge the trap with a few tablespoons of water
8. Replace all the other parts in reverse order from 4 to 1 with pipe sealer on the threads.
This can be a real PIA, but if the trap is plugged with sludge, then no control or gauge connected thereto will be accurate.

Good luck.

EDIT. the teflon tape on the pipe and fittings indicate that this has been done at least once since the boiler was installed.
Also. there are missing gauge glass guards on the boiler. That glass can get hit and break.

Then you will have an emergency on your hands resulting from breaking glass. LOL https://www.supplyhouse.com/Weil-McLain-563-334-580-Water-Gauge-Glass-Guard. You need two.

Towards the end of last winter the system began to require smacking around to kick start it. I finally got around to opening the pigtail up, and yes it was completely blocked. Cleaned it all out. I am ordering a t-fitting and will place an additional 3 psi gauge there. I found the missing glass guards, they were actually on top of the boiler! You can see them in the original picture. I guess we all missed them. Thanks again to everyone who helped. I will post again once this is tested for the upcoming heating season.

PS, I subscribe to the newsletters. I recently visited Fraunces Tavern in NYC which was mentioned a few weeks ag... what an amazing place! Recommend for any history buffs out there.

BobC

Don't buy gauge glass guards, a length of 8-32 threaded rod and a couple of nits does the job just as well. Just cut the rod to length and thread a not onto each one.

parity_check21

BobC said:

Don't buy gauge glass guards, a length of 8-32 threaded rod and a couple of nits does the job just as well. Just cut the rod to length and thread a not onto each one.

The last person to service this left them on top of the boiler. This was before my time here. The guards are back in their home.