Fittings to add gauge and vaporstat

RedHerring

Hi,
I’m trying to get on top of some issues in my one-pipe steam system including dirty water and hissing vents. I’m trying Rectorseal 8-way and I will be replacing some radiator vents. Both mains have Gorton #2’s that seem to be doing at least some venting and get warm within 10 minutes of firing the boiler. But I think it will also help to lower the system pressure. I have my pressuretrol set all the way down at 1.5 psi cut-out, but I recently babysat my boiler for an extended run and found that it took 54 minutes to cutout, at which time the pressure gauge (0-30 psi, not ideal) read almost 3 psi. At 44 minutes a couple radiators were hissing loudly and this thing was blasting a full 10 minutes beyond that before cutout. I think I have a significantly oversized boiler (10-year old Williamson gas-fired).
Below is a picture of my existing pressuretrol and gauge. With all the dirty water I’ve had I imagine the pigtail might be clogged which might be part of the problem, but I also don’t have a good pressure measurement. My plan, also shown below in a crude sketch, is to remove the pigtail and replace with two branches, with the left side holding the existing control and gauge, and the right side having a new 0-4 psi gauge with a spot for potentially adding a vaporstat, with a valve so I can close it off if it starts misbehaving and go back to relying on the pressuretrol. This is all brass 1/4” of course. This will immediately at least give me a clean pigtail and a much better gauge and I am thinking to add the vaporstat soon.
I have a few questions about this setup:
- Is this a lot of weight to sit on one nipple connecting this to the boiler? I don’t seem to have any other tapping on the boiler I can use.
- I’m concerned about the long horizontal stretch where water can pool. I thought about using some kind of wye and a 45 elbow to make the horizontal branches be angled up instead, but supplyhouse doesn’t seem to carry anything to do this. I suppose I could at least have a 90 elbow on the 4” nipple so the first tee is sitting vertical.
- From what I’ve read here I can just wrap threads in teflon tape and it should suffice for a good seal--right?
- With the union there, would it be ok to open the right-side union to dump in liquid Rectorseal? It would be a lot easier than removing the safety valve, but I wonder if brass would not like being in contact with undiluted Rectorseal. I’d flush it down with water of course.
Thanks for any advice!

Jamie Hall

That will work nicely. Make sure that you have enough clearance from the boiler to turn those pigtails -- or just move those two unions to below the pigtails rather than above them.

JUGHNE

Often the pipe nipple going into the boiler needs to be cleaned/checked.

Usually there is a reducing bushing into the boiler. I remove that and use a full size nipple there with a tee and plug to clean into the boiler.

Then nipple up to another tee and nipple either way to another tee with plugs.

You could use 1/2” for fittings, just reducing for the pigtails.

You could use cross fittings for more clean outs if desired.

Just less to take apart each year.

EBEBRATT-Ed

I wouldn't put all that on 1 pigtail. Too much to take apart and clean

Take the relief valve off the boiler and take the coupling off the relief valve nipple and install a 3/4 x 3/4 x 1/4" tee (or 1 x 1 x 1/4" depending on the size of the relief valve) and a 1/4" 90 and your pigtail with the new gauge and vaporstat.

RedHerring

@Jamie Hall that's a good idea--the more I think about it the more it makes sense to move the unions below the pigtails. Also good for cleaning or replacing them.
@JUGHNE I thought the pigtail went straight into the tapping, but you're right if I look closely I can see a bushing, but it's mostly buried in insulation. I'm thinking I might just leave that one alone. Actually I didn't ask about removing the existing pigtail but I'm hoping I can just unscrew it and screw in a new one and nothing will get mad at me.
@EBEBRATT-Ed that's a really neat idea. I'll still want to replace my existing pigtail which is probably full of gunk, but I like the idea of putting the new stuff off of the safety release port instead of having this big branched contraption.
Thanks everyone for your input!

ethicalpaul

It was suggested to me by the group to use 1/2" pipes to create a water trap. Everything after the trap is safe from steam. You can put drain valves or plugs wherever it makes sense to make cleaning a piece of cake. I used various professionals' install photos from this fine forum to make mine shown below:

https://us.v-cdn.net/5021738/uploads/editor/4n/39arh789bkak.jpeg

RedHerring

@ethicalpaul gosh, that's beautiful. But it leaves me with a bunch of questions.
-I see that the trap takes the function of the pigtail. But why have the 0-30 gauge off the wet part of the trap?
-What's with the little hose on top at the left side?
-What kind of metal am I supposed to use for this? I thought brass was the way to go but that's not what you used.

ethicalpaul

Great questions!

1. The 0-30 gauge is the one that shipped with the boiler and has an internal syphon. It's purely decorative (for code conformance). It doesn't work at all, especially at the pressures I run.
2. The little tube is to attach a very low pressure Magnahelic gauge that I like so much
3. You can use steel pipe and iron fittings for this. Brass is advised on a 1/4" pigtail because they are so easy to clog. I used 3/4 but the pros all use 1/2. I just had a lot of 3/4 fittings on hand.

veteransteamhvac

Here's some pics of a relief valve install. It works fine.

reggi

@ethicalpaul Curious if you have tested your pressure through a more conventional setup with your ultra low pressure gauge to see if there's any variation as opposed to drop manifold as I've wondered if the boiler pressure VS the water volume in the manifold would skew the precision that the gauge affords in the results. Purely something of my own curiosity...

JUGHNE

This had the bushing removed from the boiler and piped full size 1/2" with black fittings.
The 1/4" risers are SS or brass, (waiting for low pressure gauge on last riser).

The 1/2" union lets you rotate the tree to get controls screwed on.

You just drain the trap, remove plugs, brush thru the 1/2" pipe, if that is clear then you can assume that the SS risers are clear.
Reinstall plugs and re-prime the trap after that.

EBEBRATT-Ed

I just can never understand the need to reprime the pigtail or trap after cleaning. It automatically refills the first time the boiler runs. Nothing gets damaged with one dose of steam

ethicalpaul

reggi said:

@ethicalpaul Curious if you have tested your pressure through a more conventional setup with your ultra low pressure gauge to see if there's any variation as opposed to drop manifold as I've wondered if the boiler pressure VS the water volume in the manifold would skew the precision that the gauge affords in the results. Purely something of my own curiosity...

There is a very small amount of variation that can occur. Like the gauge will show a slight negative pressure between firings due to the water trap. That can happen with a pigtail too. Not enough to bother me but it bothers some.

RedHerring

OK... this noob is now really wondering what metal I should use. I had been planning all brass. If I instead have the pigtail etc attached to a tee coming off the safety release valve, should I use something other than brass? The existing coupling there is some flavor of iron.

ethicalpaul

If you're using a pigtail, make it brass. They are only a few bucks more than steel. If you are using 1/2" pipe you can use steel.

Don_175

I also would like to add a low pressure gauge. In my current installation, there is a straight brass pigtail. Then above that is a tee with the standard gauge on one leg and then the Pressuretol above the gauge on the remaining leg. I would like to replace the tee with a brass 4-way cross. The gauge and pressuretrol would then be reinstalled as existing now. I would then take a 1/4" brass nipple off the 4th connection (horizontal) on the cross and elbow up to the low pressure gauge. Does this seem reasonable? I know some people have recommended a shutoff valve to protect the low pressure gauge. Is that necessary? I see that some installations, like Paul's don't have it. Thanks

ethicalpaul

Yes that is fine. You don’t need a valve if you’re above the pigtail and your pressure stays within the range of your meter’s allowable pressure.

put a union on there so it’s easy to remove the cross to allow cleaning the pigtail

Don_175

ethicalpaul said:

Yes that is fine. You don’t need a valve if you’re above the pigtail and your pressure stays within the range of your meter’s allowable pressure.

put a union on there so it’s easy to remove the cross to allow cleaning the pigtail

Sounds like a great idea. Also, I was going to put an elbow on the horizontal 4" nipple that comes off the cross and then screw the low pressure gauge directly onto the elbow. Since it is above the pigtail, it shouldn't need a nipple to make it higher than the elbow?

ethicalpaul

Right, it doesn't know or care how high it is above the water trap in the pigtail. Height after that is meaningless, there's just air up there.

SteamingatMohawk

Valve or no valve is a constant, consistent subject of conversation on HH.

The issue is that most low pressure gauges are structurally capable of something like 130% of full range. It depends on the gauge. So, a 0-3 psig gauge will only be good to 3.9 psig. The relief valve is set at 15 psig. If a pressure excursion occurred the gauge could leak or worse depending on how high the pressure goes.

For technical and risk avoidance reasons, I strongly urge anyone adding a low pressure gauge to either not have it permanently installed (that's an annoyance) or install an isolation valve immediately before the low pressure gauge, so it can be on line only when it is needed for monitoring. Do not let it isolate anything else needed for routine operation.

Some don't have that same perspective. To me, it's a small price to pay.

Don_175

SteamingatMohawk said:

Valve or no valve is a constant, consistent subject of conversation on HH.

The issue is that most low pressure gauges are structurally capable of something like 130% of full range. It depends on the gauge. So, a 0-3 psig gauge will only be good to 3.9 psig. The relief valve is set at 15 psig. If a pressure excursion occurred the gauge could leak or worse depending on how high the pressure goes.

For technical and risk avoidance reasons, I strongly urge anyone adding a low pressure gauge to either not have it permanently installed (that's an annoyance) or install an isolation valve immediately before the low pressure gauge, so it can be on line only when it is needed for monitoring. Do not let it isolate anything else needed for routine operation.

Some don't have that same perspective. To me, it's a small price to pay.

I hadn't thought of the gauge coming apart. I was thinking more of just malfunction. This would require the pressuretrol to malfunction as mine is set for a cutout of 1.5 psi. I agree that a shutoff valve is cheap insurance.

SteamingatMohawk

True, but if the pressuretrol doesn't trip, what could the pressure in the system become? Failure of the system to shut down for whatever reason is the concern.

ethicalpaul

It could become 15 psi then the relief valve blows, if it's not gunked up that is. But at that point the last thing I care about is my low pressure gauge.

ChrisJ

Ditch the valve and use a quality low pressure gauge like a Magnehelic.

They will tolerate 15 PSIG without any damage or effecting their calibration. Even one intended to measure pressures as low as 1oz full scale. And they can be found on eBay all of the time for prices in the neighborhood of cheaper gauges.


I have a 1/2" valve on the siphonless setup I use with my Magnehlic but it's only there in case I need to replace something with the boiler running. My low pressure switch is on the same assembly so I can't turn it off during normal operation.



Or, use a valve, it's not hurting anyone.
Except if you shut a valve off while it and the piping are hot, but reading 0 pressure it will pull the gauge into a vacuum as it cools. I have a feeling this isn't good for a Bourdon tube gauge.

reggi

I have a 30 ounce gauge valved off for the simple reason if I'm not there to look at it, it doesn't need to be turned on..
And I do go into vacuum and the gauge doesn't, And if the Gauge at least than 2 psi ruptures it will release the boiler Steam into the basement and not satisfy the thermostat nor trip off in pressure... just cut off on low water.. until it auto refills and continues until I get home or the steam attracts attention
So I leave the 30-0-30 on...and the 30 ounce valved off
Just my way of thinking though..I sleep well

Don_175

I bought a shutoff valve. I'd like to sleep well too!!

ChrisJ

Honestly.

If a $30-40 pressure gauge that doesn't even do anything useful 99% of the time is stopping anyone from sleeping, there's something seriously wrong.

SteamingatMohawk

@ChrisJ I fundamentally like the Magnehelic option. Anything that can handle 15 or above is probably OK. I just don't know if it should be the full range of the required gauge (30), which I admit is kind of overkill.

Yesterday I looked at the Ptrol P404A cut sheet and it says max operating pressure of 20psig and ambient temperature of 150F.

So, what is the right number? Probably a fair argument would be the Ptrol number, since they have been around for decades more than us and have certification.

You have a lot more experience with Magnehelics. Can you identify a model that has the right range and can handle 20psig?

ChrisJ

@SteamingatMohawk

20psig for a home heating system?

What about the vents?

The block is literally tested and rated for 15 psig.

reggi

ChrisJ said:

Honestly. If a $30-40 pressure gauge that doesn't even do anything useful 99% of the time is stopping anyone from sleeping, there's something seriously wrong.

You are certainly entitled to your opinion and as long as you aren't Stating this as FACT then a person is of free will to decide what is best option for their safety, investment, household, family,peace of mind, and on and on...
Just because you do it doesn't mean it's right for everyone to... you installed your own boiler and threaded your own pipes if I recall... you're intimate with your system 👀

Edit: And don't you use a 18" pipe off the top of boiler for your gage anyway?

ChrisJ

Jeez it's been a long day and I just deleted what I typed.

I'm heading to bed.

EBEBRATT-Ed

Low pressure gauges are easy to damage especially the cheap one's. Valve or no valve doesn't matter to me

SteamingatMohawk

We all have our own perspectives. After having my son live through a baseboard hot water system failure in a house I owned while he was away at college, including condemnation of the house until repairs were made and being a landlord, I tend to be risk averse.

Protective devices are meant to avoid major problems; the assumption is that components in the system are of sufficient structural and functional capability. Permanently installing a low pressure gauge without adequate isolation violates the concept.

That's why I advise against it.

@EBEBRATT-Ed The valve costs about as much as a replacement gauge, anyhow.