Hi, I am replacing a Mater pressurestat (after 6 years of use) with a Sirai - does anyone know the corresponding terminals between the Mater and the Sirai? Any help would be greatly appreciated.

George

George -

It would help if you identify what machine is scheduled for this surgery.

The MA-TER pstats typically have three terminals, C (Common), NC (Normally Closed), and NO (Normally Open). Sirai pstats typically have three electrically independent sets of contacts and usually only one set (C & NC) is used.

Hi Eric,
It is an ECM Cellini (same internals as the ECM/Rocket Giotto). I don't have the machine right in front of me, but I know the NO terminal is left open. The white wire (if the colours even mean anything) is coming from the, I believe, high limit temperature switch, and the black wire from somewhere else (never tried to trace where it went). Is that the kind of info that sheds any light on the question?
Best regards,
George

Well George, it is pretty simple now as it sounds like the existing MA-TER only has two active terminals and they are connected to the existing pstat with female spades. Just get some short sections of similar colored (and gage) wire and crimp male spades on one end of each. Crimp a forked terminal on the other end. Cover any exposed metal with electrical tape or heat shrink tubing.

The Sirai pstat is best wired with fork terminals but it can accept simple stripped leads. The Sirai pstat has 6 connections in two rows. Connect one wire to a terminal in the top row and the other to the corresponding terminal in the bottom row. It does not matter which wire goes where.

As an aside, why are you replacing this MA-TER pstat - six years is faithful service ??

Thanks for clearing that up for me! As for the Mater, it is not actually being replaced (yet, anyway). The Sirai was recently purchased (for about $20cdn more than a Mater would have cost me) as a back-up for the day that the Mater does finally quit on me. Just wanted to test drive the Sirai to make sure it works properly so that I am not stuck when the day comes with no replacement p-stat. The Mater has worked beautifully everyday for several hours per day (not 24/7) for just over 4 years (I was wrong in my earlier post as I forgot that it was a replacement for the original CEME that lasted for just over a year before it got stuck and kept letting the boiler overheat). Given how many people seem to scorn the Mater p-stat, I have had the opposite experience with a good one that has had a consistently steady deadband of just over 0.1 bar the entire time. I would not hesitate buying it again in the future, but thought for $20 more I would give the Sirai a shot (and I understand that they use a different material for their membrane than the one that used to harden up on certain machines).

George

On a different note, anybody ever try cramming a Sirai into an Anita? I'm probably about due for a p-stat failure and would like to upgrade a bit...

Mike

That I don't know, but Sirai now makes a smaller p-stat (model 303) that is the same height and width but almost half the weight and length - this might be of interest to you.

George