Adjusting Pressuretrol Options

MikeBlue

I haven't had any luck being able to adjust my pressuretrol down to 0.5 psi. I've turned it down to the lowest point possible before the screw and spring pop out. Even though the pressuretrol's little gauge is below 0.5 and set to cut out at at 1psi above cut in, the boiler is cutting out at 2 psi. I haven't heard anything positive regarding the Honeywell pressuretrols. Is this problem common, is there someway to still go lower, is there another control I can use to replace the pressuretrol and more accurate control? Thanks.

Jamie Hall

It isn't a problem...

it's just the way pressuretrols are built, and what they are meant to do.  They aren't meant to control pressure in the 1 to 4 psi range, really, although they can be persuaded to run with a cutout below 2...  most of the time...



The solution is a vapourstat.  Pricier.  They come in two flavours; one group has a 0 to 16 ounce per square inch range, the other group has a 0 to 4 pound range.  If you have a "normal" two pipe system, or a one pipe system, perhaps the 0 to 4 pound is the way to go; a vapour system would use the 0 to 16 ounce.



That said, how accurate is your pressure gauge?  If it is the code required 0 to 30 psi gauge, it may not be all that accurate at the low end.  What does it read when the system is cold?  That can be a hint... they often don't quite read 0.

BobC

Vaporstat and or a low pressure gauge.

I assume you have the internal wheel set to one.



Pressuretrols are just not very good and the newest ones appear to be worse than the old style was. A vaporstat gives much better low pressure control but they cost about $80 more. Also trying set either one using the 0-30PSI gauge is usually fruitless, try installing an auxiliary 0-3PSI gauge so you can see whats really going on.



Bob

AlexT

I had the same problem

Mike - I had the exactly same problem with my Pressurtrol (see http://www.heatinghelp.com/forum-thread/134267/Pressurtrol-or-Vaporstat for my experience).



Mine would cut in and out at 1.5 - 2.5 pounds no matter what I did. I found a cheap replacement on Ebay and now I get .5-1.5 pounds consistently.



A Vaporstat is in my future since I can tell my system generates a lot of steam at just a few ounces of pressure. Too bad they're so expensive.

JohnLaPlante

Cutout Plus Differential

Hi Mike,

Forgive me if you know this...but I had the same question about 3 weeks ago:)

The boiler cutout is controlled by the screw at the top PLUS the dial inside the pressuretrol (differential).  So if you have the screw at the top set to 0.5, but the dial inside the pressuretrol set to 1.5, then the boiler will cutout at 2psi.

I am a total newbie to this, but I had the same question and this is how the great people here answered it.