Vaporstat model

RyanC

I would like to put a vaporstat on my system.  Right now I have an ancient pressuretrol on a  one pipe system. Can someone suggest what model vaportstat I should use?  I cant really seem to tell the differences between them.

Thanks,

Ryan

SteamHeat

Most Folks Use

The Honeywell 16oz. unit.  Some people have had trouble with them, but more folks seem to be okay with them. They chatter at about 8 oz. for a second or two. Make sure you have good venting on your mains or pressure will build up too quickly and you will hit cut out prematurely.

Alan (California Radiant) Forbes

Honeywell

L408J1009 Vaporstat (non-mercury) 0-16 oz. (4-16oz. subtractive differential).  They seem to be the only ones available now that mercury is verboten.



Here is a thread on them:

http://www.heatinghelp.com/forum-thread/128249/why-do-Honeywell-vaporstats-suck-so-badly

RyanC

Thank you!

Thanks for the info!

Mike Kusiak_2

Check on ebay

There are aways some NOS mercury vaporstats on sale on ebay. Right now there are 3 mercury L408B models offered at $14.99 with no bidders. Just do an ebay search for vaporstat.

FJL

Why So Cheap . . .

Are those v-stats priced at $14.99 because they are made with mercury?  The non-mercury v-stats are priced at $169 or higher.

Mike Kusiak_2

Old discontinued model

Those particular vaporstats are long discontinued, and look like they have been sitting on the shelf for years. Probably built a lot better than what they make now, though.



I have seen the most recent mercury model, new in box sell in the $40 range. A lot of the controls sold on ebay are surplus from companies going out of business and sell for way under wholesale prices.

FJL

Most Recent Model

The most recent mercury model would be on in which the mercury switch is visible in a clear plastic box?  I have a 0-4 psi mercury v-stat, but I would have preferred a 0-16oz mercury v-stat.  The latter are easier to set for under 1 psi assuming the indicator is accurate. 

Mike Kusiak_2

Last mercury model

Yes, the latest mercury model has the clear plastic face, and the 16 oz model does turn up on ebay occasionally. Save the search for vaporstat on ebay and they will notify you by email when one is listed for sale.



You are probably better off with the 4 PSI mercury model you have , than with the current non mercury 16 oz. model. The non mercury model uses a mechanical microswitch controlled by the pressure diaphragm, which requires significant force to actuate. The mercury switch only needed a slight force to tip the glass mercury tube, making its action more accurate and repeatable.



Too bad Honeywell did not redesign the vaporstat using an optical or Hall effect sensor. They could have produced a product even more accurate than the mercury model, but instead chose the easiest and cheapest way out.

jpf321

vaporstat models...

If you are referring to the confusion between the 4 different L408J models .. have a look at http://customer.honeywell.com/techlit/pdf/PackedLit/65-0287.pdf the table in upper right of Pg. 2 where it describes the diffferent "switching actions" of the different models .. i ordered mine from patriot-supply.com (ACTUALLY from ebay with them as the seller, I do not think they had the 1009 on their website) .. i got the 1009 (0-16oz break RB; make RW) for $193 and wired it in just fine in series with my p-trol.



HTH, jpf

FJL

1009

What is the signifcance of the "Breaks RB; makes RW"?

jpf321

RB RW

There are 3 screw terminals .. I only used the RB terminals .. when the pressure is achieved, it "breaks" the circuit using 2 screws .. it would "make" another circuit at that point. perhaps another way to think about it .. screws: B R W .. R being used in always .. pressure down .. BR is connected .. pressure up .. RW is connected. I do not have anything connected to W .. only BR (which is break circuit when pressure reaches cut-out) ..



This is the way that I understand it .. since this is line voltage electricity DO NOT TAKE WHAT I SAY AS ABSOLUTE OR CORRECTNOR RISK YOU OR YOUR FAMILY'S LIVES ON IT .. check with a Professional or a licensed electrician.



I think they have circuit diagrams in the above PDF.

FJL

No Need To Worry

DO NOT TAKE WHAT I SAY AS ABSOLUTE OR CORRECTNOR RISK YOU OR YOUR FAMILY'S LIVES ON IT

LOL.  No need to worry about that.  I'm relucant to install a pressure gauge on my boiler for fear of messing it up.  I would have no reluctance but for the fact that there are three other families that share the boiler in my building and they'd crucify me if I did something wrong and damaged something. 

jpf321

but wouldn't they

but wouldn't they love you for saving overall heating costs if you properly cycled at the lowest possible pressure? 

FJL

I did lower the pressure . . .

I did lower the pressure recently, and I've noticed some things.  The rads are quieter.  The pressure inside the rads (at least the one for which I have attached a low pressure gauge) doesn't rise as quickly and it is more stable.  Also, the boiler runs longer after cycling off due to pressure than it did before, the latter occurring mostly during setback recovery.  I still get that "whoosh" sound of air returning into the system after the boiler cycles off.  Not sure how to reduce or eliminate that.