Pressure not reading

Paulvar1

On my Brand new Well McClain boiler, my pressure Gauge always reads Zero. The Honeywell Pressuretrol is connected to it on the pigtail. It works great. I tried buying another Gauge and that too reads zero even when steam is built up to the point when the Pressuretrol kicks out. The pigtail basically has a T one leg to the gauge the other to the Pressuretrol control. It is new. I would like to know the pressure in the boiler to adjust the system. The plumbing contractor had the Pressuretrol cut in set at 2 with the cut out wheel set at 2 (additive being 4). I want to dial it down to 1.5 lbs total. How do I get the gauges to read ?

pecmsg

Gauges are most accurate when reading in the middle of the scale. That boiler requires a 0 - 30# gauge by law. you'll never see 1 or 2# reading on that. get a 0-5# gauge and T it in the line with a valve!

HarryL

You are on the right track for sure. Just to be sure though, how do you know that the Pressuretrol is what is shutting down the boiler? What is the range for the gauge? While 4 PSI might register on a 0-30 gauge, if the pressure is in fact lower, you might not see the 0-30 gauge budge. A picture of the pressuretrol and gauge would be good to know what types are involved.

LS123

@Paulvar1 , depending how old your boiler, you may have a 0-30 PSI gauge on front mounted. You may have P-trol and another Pressure gauge on the pig tail. I have a 0-3 PSI on the pig tail, it is the most accurate reading I get, and P-Trol gets activated when cut off, cut in are reached. Often on 0-30 I see PSI about 2, but 0-3 PSI indicates much lower PSI and mine start pushing steam to supply lines and rads when PSI is about 0.25 - 0.5 PSI on the low pressure gauge. Most home boilers should have a cut off at 1.5 PSI on P-trol.

EBEBRATT-Ed

@Paulvar1

You can install all the gauges you want it is not necessary to build pressure to heat your house. If the house is heating well and the system works correctly you may never see pressure on your gauges and everything is fine. It means your boiler is correctly sized

Paulvar1

I bought an additional gauge, both are 0-30 !! What website can I get a 0-5 gauge ? the supply house near me said that they dont have such an animal.

Neild5

You can get it from Amazon,  https://smile.amazon.com/Capsule-Pressure-Connection-Adjustment-blackSteel/dp/B086942GKG/ref=mp_s_a_1_4?dchild=1&keywords=0-3+psi+pressure+gauge&qid=1613695742&sprefix=0-3+ps&sr=8-4

lockdown_lou

I recently installed the gauge linked above on my boiler.   It turns out that unless recovering from a setback I don’t build more that 0.1 psi of pressure.   Some cycles (1 cycle per hour),  the low pressure gauge doesnt even flutter.

Some fast vari-vents and leaky packing nuts undoubtedly help with this. 

ethicalpaul

What about after the vents close against steam? Does your pressure build then?

Regardless, look on ebay for "dwyer magnehelic" and you'll find one with an appropriate range to show you what pressure you are running. I recommend the 0-5 inches of water scale, but 0-10 would be fine too.

SteamingatMohawk

@ethicalpaul is right on. Make sure the label says " max pressure 15psig", which most do. Or spend a little bit more and get a new one.

SteamingatMohawk

@Neild5 The gauge you are using is most likely not suitable at pressures above 130% of the gauge range (3psig *1.3 = 3.9psig), so install a valve so it can be isolated when not in use or don't leave it connected all the time. See other discussions on HH about the low pressure gauges.

SteamingatMohawk

Or get what @ethicalpaul suggests

EBEBRATT-Ed

I don't think we should be promoting the fact that if the boiler doesn't build pressure there is something wrong with it. Why fiddle with a pressure control if the boiler won't build pressure?

If it heats the house well leave it alone

ethicalpaul

Of course you’re right. But seeing the back pressure can still be interesting and informative for some folks

LS123

@EBEBRATT-Ed , @ethicalpaul , you both are right... I have experienced similar with old 0-30 pressure gauge....I spent nearly 4 years with a old but really good boiler. It had a old front mounted 0-30, and one 0-30 on pig tail. sometimes in the past, psi indicators would be t 0 (on old 0-30) but it heated the rads and kept the house heated. When I replaced the pigtail gauge with 0-3, sometimes it would heat the rads at about 0.1 psi, someday it would climb clime and stay between 0.25 and 0.5 psi on low pressure gauge. As I have learned in this forum, old 0-30 don't move the gauge noticeably enough.
Best!

Neild5

SteamingatMohawk said:

@Neild5 The gauge you are using is most likely not suitable at pressures above 130% of the gauge range (3psig *1.3 = 3.9psig), so install a valve so it can be isolated when not in use or don't leave it connected all the time. See other discussions on HH about the low pressure gauges.

Thanks for the tip. There are 2 control circuits and a safety that protects the gauge. There is a pressure transducer that signals the controller to moderate the burner from 100% down to around 30%. Then there is a vaporstat set for 2 ounces above the transducer and a manual reset pressuretrol at 2 psi cutout. I realize failures can occur but 3 independent circuits would all have to fail for the gauge to reach 2 psi.

SteamingatMohawk

Can the gas valve stick open?

With that logic, you don't need the 15psig relief valve.

We can agree we have different perspectives and leave it at that.

EBEBRATT-Ed

And if the boiler never leaks you don't need a low water cutoff. Worked when they burned coal

vincentac1

If it is a steam boiler and you have a gauge that reads psi then you would have a problem if it reads anything due to the fact that it runs in ounces. the psi gauge is the governments little attachment. to give you some perspective the empire state building only runs on 2 pounds of steam.