Replacing an old Honeywell pressuretrol with a newer model - which one?

Powe

I tested my pressuretrols this weekend (micro switch not mercury) and the differential on the high limit control has failed. Cut in and cut out are the same and adjusting the differential makes no difference, across the entire pressure range of the control.


I've been thinking about replacing these with the newer pressuretrol or vapourstat but I am confused about which model to select. I seen pictures of boilers with two installed, just like mine with the older model, and some where only one is installed. What is the proper way to do this?

First, I am unclear what the difference is between a Pressuretrol and a Vapourstat?
What pressure range should I get? 0-4psi? 0-15? 2-15?

I am thinking I should get one with the manual reset for the high limit cut off (assuming I get 2 of these or just leave the (still functioning) older ptrol in place for now).
Do I need two? Or do the newer models have the high limit built in?

FYI, the still functioning old model is set as low as it goes (.5psi) with at 1psi differential and my tests show the cut-in at 1.2psi and cut out at 2.2. The highest pressure I've ever seen on my low pressure (0-3 psi) gauge is .5psi.

Thanks.

Jamie Hall

If your system is comfortable running at 1. 5 psi -- it's not a vapour system -- you don't need a vapourstat. They are nice to have -- much more precise and can be set to a lower pressure range -- but kind of pricey. The pressuretrol you show in the second pricture will do just fine.

Many residential codes do not require two pressuretrols on residential boilers. I like to see two, and larger boilers require one. The higher pressure one should be manual reset, if only to encourage the operator to think for a bit about why it tripped.

ethicalpaul

Many residential codes do not require two pressuretrols on residential boilers. I like to see two, and larger boilers require one

Did you mean "larger boilers require two"?

Powe

Jamie Hall said:

If your system is comfortable running at 1. 5 psi -- it's not a vapour system -- you don't need a vapourstat. They are nice to have -- much more precise and can be set to a lower pressure range -- but kind of pricey. The pressuretrol you show in the second pricture will do just fine.

Many residential codes do not require two pressuretrols on residential boilers. I like to see two, and larger boilers require one. The higher pressure one should be manual reset, if only to encourage the operator to think for a bit about why it tripped.

With my limited knowledge and experience, and what I've read, I agree about having two pressuretrols.

You didn't reply about the pressure range...
I see Supply House has a 2-15psi manual reset that looks like the one I should use for the high limit?

And if I replace the low pressure switch, I am thinking that this 1-8psi auto-cycle model (differential is subtractive) would be the best one to choose. As I mentioned in my original post, I rarely see any pressure on my gauges at all, so my system is running at a few ounces at most.

Am I on the right track here?

Jamie Hall

Yes. And @ethicalpaul caught me... I did mean two. Oops...

Powe

Jamie Hall said:

Yes. And @ethicalpaul caught me... I did mean two. Oops...

I wasn't fooled! Lol. I took you to mean that the commercial boilers need the "secon" one. 
Thanks for the feedback. I've got a few things on my list for Supply House. Not sure I'll buy the second pressuretrol right away but it's on my wish list!
Thanks.