Low pressure gauge

Zipper13

I want to add a low pressure gauge paralell to my pressuretrol - on a tee after the pigtail. I'm debating spending the money on a vaporstat for this hoffman system, but first I really want to understand how often the pressure actually ticks up so I can weight if it's worth it and understand the trends in how it runs.

I notice that many low pressure gauges on supply house .com for example state that they are not for permanent installation and only for "temporary" diagnostic use.

Is that just stated for the manufacturer's own legal protection in case they do fail or are they really only meant for temporary installation/use?

Can anyone point me to to a lp gauge that would work for me to add permanently on my residential burnham?

Fred

@Zipper13 , This is the one a lot of us use:
https://www.pressureworx.com/product/low-pressure-gauge-25-0-3-psi

EBEBRATT-Ed

@Zipper13

Install the low pressure gage. Put a 1/4" ball valve or pet cock under the gage. Leave it shut off. You only need to open it when your down there checking the pressure.

I would spend some time adjuasting the pressure control you have. With some tweaking you may avoid a costly vapor stat

Keep in mind residential steam systems are not supposed to build pressure. Not building pressure is a result of having proper venting and a boiler of the proper size

Jamie Hall

Does your Hoffman system still have the Differential Loop connected?

If so -- first, a vapourstat is not an option. The maximum pressure differential for a Hoffman system is 6 ounces per square inch, and there is no way you are going to achieve that without a vapourstat as your control. You can leave the pressurestat as a backup safety, if you like.

Second, check the arrangement of your venting. The Hoffman system is designed to be used with crossover traps and all the venting concentrated where the dry return(s) enter the top of the Differential Loop. Any other arrangement will not work properly, and lead to either no heat in all or part of the system or very poor heat. I repeat: there must be no venting anywhere on the system except right where the dry return(s) come into the Differential Loop.

mikeg2015

0-15” here: https://www.supplyhouse.com/Winters-Instruments-PLP300-2-5-Steel-Low-Pressure-Gauge-0-15-Water-OZ?gclid=CjwKCAjw-4_mBRBuEiwA5xnFIBjvX0EGXILbLMmZ2wXLlKjag4X4tG2BFEl3BzfwvASdrXgnm25j7RoCtdUQAvD_BwE

For very low control (but not safety limit) I’m going to try out using a adjustable furnace pressure switch that I can dial down to less that 1oz for engaging low stage.

Jamie Hall

ON a Horrman Equipped -- that will be OK certainly for the high to low -- but unless your venting is correct, you still need to cut out the low fire at 6 ounces. If your venting is correct, you can go over that without damaging anything -- you'll just waste a lot of fuel without much to show for it.

Zipper13

Thanks for the input everyone. I hadn't thought about just putting a valve before gague duhh.

Yes, Jamie, still have the diff loop with original #11 vent on top Its the Only vent on the system, I do plan to to add a bigmouth on an antler with the hoffman 11 to speed venting. Cross over trap is working great too.

I've heard so many complaints about the honeywell vaporstats lately that I guess I'm maybe I'm trying to convince myself a way not to buy one...like maybe with the gauge there I could calibrate the pressuretrol to do it, but rationally I know it's not designed to be that precise.

Jamie Hall

The problem with the pressuretrol is really two problems -- first, it's not designed to be reliable that low, and so it isn't. The second, related, is that at very low pressure they are erratic -- not so much that they won't turn off (eventually) -- they will -- but that they may not turn back on.

The newer microswitch vapourstats do tend to be a bit twitchy, and often need to be calibrated (with that handy low pressure gauge!). They aren't impossible, though. That said, the mercury switch ones do show up on Ebay from time to time -- this one is up as I type: https://www.ebay.com/itm/Honeywell-L408B-Vaporstat-NEW-in-Box/302907476037?epid=884722077&hash=item4686b14845:g:QN0AAOSwdzRbtROG:sc:USPSPriority!06057!US!-1

They are bullet proof. They do need to be mounted very carefully and levelled very carefully, but you can't kill them.