Residio PA404A

EBEBRATT-Ed

These controls are awful.

I just installed a new one to replace one that was full of gunk and replaced a steel pigtail that was blocked up with a new brass pigtail and a new control and checked the connection into the boiler. The safety valve was relieving at 15psi and scared the HO half to death.

I played with this thing for a while and with the diff set to 1 the lowest it will go is 2 1/2 CO and 1 1/2 CI and I put a temp new 0-5 psi gauge on a tee under the pressure control that I used to adjust the control

Junk and it ought to work for the $$$ it cost

ethicalpaul

They've been bad for probably decades, don't let the new name fool you it's still the same old Honeywell product.

Alan (California Radiant) Forbes

What's the better replacement? These have been around forever.

mattmia2

the ones with the mercury switch...

SteamingatMohawk

I traded emails with Resideo with the following situation:

I bought a new one, set it at 0.5 cut in and 1.5 cut out. They said the tolerance on the cut out is +/- 1.0 psi, which means the cut out could be 2.5 more than the cut in or a total of 3.0. Since my cut out was 2.6 they said it was in spec.

After that set of emails, I got frustrated and went on to something else.

A few days later, I consulted with a very well known and revered retired steam guy who told me, "They're officially telling you that the thing is not suitable for steam heating at low pressure. It hasn't been since they got rid of the mercury switch."

I think the pressuretrol in its modified form even without the mercury switch is such a cash cow for Honeywell/Resideo that they aren't going to do anything, even if the installers and users scream and yell.

Maybe the vaporstat or something from a different manufacturer is the long term solution.

Since low pressure is "King", maybe we all should replace the pressuretrols and send them to the president of the company as gifts.

Jamie Hall

You'll have to pry my mercury vapourstat out of my cold dead hands.

The Steam Whisperer

You may want to try the Penn P47AA-1C. I have had about 10 of these in service for awhile and will be seeing this week how well they operate at low pressures.... 0.5 cut in and 1 psi cut out.

ethicalpaul

The answer is to make sure your boiler is sized right then the switch will never have to activate

ChrisJ

ethicalpaul said:

The answer is to make sure your boiler is sized right then the switch will never have to activate

Agreed

They're plenty suitable as a high limit that shouldn't normally be hit.

Proper boiler sizing and proper venting should avoid the issue.

Jamie Hall

ChrisJ said:

ethicalpaul said:

The answer is to make sure your boiler is sized right then the switch will never have to activate

Agreed

They're plenty suitable as a high limit that shouldn't normally be hit.

Proper boiler sizing and proper venting should avoid the issue.

I really enjoy optimists... whether for better or worse, engineers cannot be optimists (or if they are, they'd better have very good errors and omissions insurance...)

EBEBRATT-Ed

I agree about the proper boiler sizing but we all live in the real world. The Penn sounds interesting. Too bad the boiler mfg won't buy in.

Maybe Hydrolevel should come out with something

ChrisJ

Jamie Hall said:

ChrisJ said:

ethicalpaul said:

The answer is to make sure your boiler is sized right then the switch will never have to activate

Agreed

They're plenty suitable as a high limit that shouldn't normally be hit.

Proper boiler sizing and proper venting should avoid the issue.

I really enjoy optimists... whether for better or worse, engineers cannot be optimists (or if they are, they'd better have very good errors and omissions insurance...)

EBEBRATT-Ed said:

I agree about the proper boiler sizing but we all live in the real world. The Penn sounds interesting. Too bad the boiler mfg won't buy in.

Maybe Hydrolevel should come out with something

Just keep that in mind the next time guys are complaining about doing manual J's or air conditioners not being sized properly. It's the real world.

I've had two different size boilers on my setup, first 150K input now 125K input. Both work more than good enough. If a steamer is building pressure fast enough to trip a Pressuretrol during normal heating cycles something is grossly wrong, either the boiler size or the venting.

Obviously boilers that are already in place are what they are, but replacements don't have to be.

That's my story and I'm sticking to it.


For a decent control to keep on the truck I'd go with : https://www.supplyhouse.com/Honeywell-L408J1017-Vaporstat-Controllers-0-psi-to-4-psi

I've always thought a 0-4 PSI was a good size for most normal things. Gives guys a good range to mess with.

The Steam Whisperer

Jamie Hall said:

ChrisJ said:

ethicalpaul said:

The answer is to make sure your boiler is sized right then the switch will never have to activate

Agreed

They're plenty suitable as a high limit that shouldn't normally be hit.

Proper boiler sizing and proper venting should avoid the issue.

I really enjoy optimists... whether for better or worse, engineers cannot be optimists (or if they are, they'd better have very good errors and omissions insurance...)

Yeah, except they are known to physically fall apart after 18 months of initial installation.

SteamingatMohawk

Is there any advantage to going with the 0 - 16 oz vaporstat?

ChrisJ

SteamingatMohawk said:

Is there any advantage to going with the 0 - 16 oz vaporstat?

Should give better control, and is more appropriate but it may also be more fragile.
The reason I picked the 4 PSI for most is it seems like many insist their systems should run at 1-2 PSI.

IMO anything over 1/4 PSI is annoying and unnecessary for residential.

EBEBRATT-Ed

problem is the MFGs won't go for the cost of a vaporstat so most residential boilers are installed with the "wrong" controls"

My problem is a brand new PA404A "should" be able to be adjusted to cut out at 1 1/2-2 psi and cut in at 1/4-1-1/2" psi and it can't be done reliably without mickey mousing the thing

SteamingatMohawk

In my situation, with the Cyclegard set at 10 minutes between and 90 seconds for the level test, I wonder if it would ever go above 16 oz/in2.

It's obviously safer to use the higher range unit, but an interesting speculation. Maybe some day when I am there for a while, I'll put in my 0-5 gauge (or get a 0-3 or make a 3 foot long manometer) and see what really happens.

Has anyone tried to modify the Pressuretrol to get the diff closer to what's on the dial? I looked at the mechanism a couple of years ago, but never tried anything on the unit I removed.

ChrisJ

SteamingatMohawk said:

In my situation, with the Cyclegard set at 10 minutes between and 90 seconds for the level test, I wonder if it would ever go above 16 oz/in2. It's obviously safer to use the higher range unit, but an interesting speculation. Maybe some day when I am there for a while, I'll put in my 0-5 gauge (or get a 0-3 or make a 3 foot long manometer) and see what really happens. Has anyone tried to modify the Pressuretrol to get the diff closer to what's on the dial? I looked at the mechanism a couple of years ago, but never tried anything on the unit I removed.

I'm not sure but if you do please make sure you have another unmodified unit in series with it just to keep things safe and code compliant.

SteamingatMohawk

@ChrisJ You got that right, even if it is one of those that can't get down below 1.5psig cut out.

My recollection is that I am not smart enough to correctly figure out what to tweak to get the switch to trip on a smaller differential. Obviously, if I did do anything I would bench test it many times to ensure repeatability. But as you have seen in my other posts, I am risk/liability averse, so it's probably a tinkerer's dream to think I could actually git 'er done.

archibald tuttle

@SteamingatMohawk "repeatability". lmk how that works out. in the NFN department I have had some luck downfiring to keep the pressure from rising to where I need a reliable operational cutout (almost any standard pressurtrol will get the safety work done). It will take longer to make steam and will affect the theoretical efficiency but I've found the additional firing to make steam is offset by the lower firing rate through out the cycle.