TRVs filling with water

mel rowe_2

Anyone have any ideas as to why the TRVs I have installed on my one pipe steam system keep filling up with water and, of course, not operating properly? Most times it is the TRV valve body that fills up, but I have also had to remove and dump out water from the vent that sits on top of the valve body. The TRVs are Honeywell-Braukmann and the vent is marked SA123A. Thanks for any help.

bb_7

The Library

Mel:

Check the library under Thermostatic Radator Valves. There is an aritlce that should help you out.

You need to have the Honeywell valve body w/ the vacum breaker. This allows the radiator to "Breath" in air whilte the boiler is off. Without breathing air in the condensate cann't drain back to the boiler.

Warm Regards,

bb

mel rowe_2

Thanks bb for the help. I'm a HO with only a little knowledge, mostly gained from people like yourself on this board and by trying things myself. Another kind gentleman led me in the same direction on this problem, and I intend to try it out, but I don't get the logic of why this would be the problem, so I was looking for any other ideas as to possible causes. I have Gorton valves on my mains. They have vacuum breakers and I can hear air rushing back into the system when it starts cooling down. Since this would relieve any vacuum in the rads, why wouldn't the condensate flow out of the TRV body and the vent that sits on top. I can't even imagine why so much water is collecting in the TRV in the first place. Doesn't seem like there could be that much condensation collecting there in such a short time. Can the flow of air/steam through the TRV be carrying so much water along with it? Do you think this would be helped or made worse by changing the rate of flow through the the vent. This problem is not happening except on a few of my many TRVs. When I take it off the rad, I find the valve body full of water, and the vent partially filled. All of this, of course, causes a lot of noise and spitting water out the vent. The combination is driving me nuts. Would appreciate any additional thoughts as to potential causes.

bb_7

system pressure

Mel:

Do you know what pressure you are running?
What type of radiator do you have?
Is the shut off vavle completely opened?

If the TRV is closed, and filled with water, the radiator can't breath air in. If no air comes in, no condensate drains out of the rad. Even if the mains are breathing this does not allow the radiator to breath.

Click on the "Find A Pro" link up @ the top of the page.

Warm Regards,

bb

mel rowe_2

The Pressurtrol cut-in is 1/2 and the diff. is set at 1. I installed a 0-5 psi gauge and the boiler hardly every gets over 1psi. I have American radiators. The shutoff valves are always kept fully open when running. Why wouldn't the TRV breathe air in when it cools off and opens up? I know I hear the TRV valve when it closes at set temp. and I thought I heard the TRV valve opening up as it cools. As we discuss this; however, a thought occurs. What if the off cycle is short enough that the room temperature never gets below the set temp. on the TRV? If that is happening and neither the TRV nor the SA123A vent valve has a vacuum breaker, then it would be difficult for the water to flow out. Think I'll check this out by changing the vent valve to an old Hoffman 1A I have lying around. What do you think about this?

bb_7

Vacum breaker

Mel:

This is why the valve needs a vacum breaker. W/O one, air will never get back into the rad when the boiler cycles off. Check with a local supply house. Honeywell does offer a vavle w/ vacum breaker. That would be the best cost solution since you have a Honeywell operator.

Putting the Hoffman on should sovle the problem, but you lose the benefit of zoning you have w/ TRV.

bb

mel rowe_2

Thanks very much, bb. I don't want to give up on my TRVs, I was just going to switch the Hoffman 1A vent for the SA123A vent that was supplied with the TRV, to see if that alleviated the water retention, while I was pursuing the other Honeywell valve body with vacuum breaker.

mel rowe

Well, I tried using the old Hoffman 1A valve in place of the SA123A, and it really did not make a whole lot of difference. Now I'm suspicious that the room is getting warm enough that the TRV does not have enough time to cool off and open up and drain fully before the steam cycle starts again. So I'm still experimenting. FWIW I checked with Honeywell and one of their engineers stated that a vacuum breaker anywhere in the system should be adequate. They had no ideas as to why I am having this problem. Also, they do not make a TRV body that has a built-in vacuum breaker.

bb_7

need a vacum breaker

Mel:

you need a vacum breaker on the rad. Try putting your finger over a straw will it sits in a full cup. Lift the straw out of the cup w/ finger over the top. Fluid stays in... Same thing w/ your rad and the TRV. If it can't get air into the rad, the condensate can't drain out.

bb

mel rowe

bb, wouldn't the vacuum be broken and air supplied to the radiator when the valve in the TRV cools down enough to open?

bb_7

can't guarantee that will happen while the boiler is off!

mel rowe

Got it. Thanks. Interestingly, I just took off one of the TRVs filled with water and found little water coming out of the TRV itself. Even when I opened the TRV up all the way to make sure the valve body was open, almost nothing came out. I had to take off the SA123A vent and shake it to get the water out. There was quite a bit being held in the vent. Are there other vents that might not have this kind of problem, when I use it along with the TRV?

Dave_4

Vacum Breaker

Well I too am suffering from the same problem. I have installed a couple of TRV's in upstairs locations hoping to keep those rooms cooler. These rooms obviously are kept too cool to allow the TRV to open enough to drain the valve. The main issue seems to be that there is no vacum breaker on the honeywell TRV.

Is there a vacum breaker that could be installed inline with the TRV. I have pleanty of room to do this.

I have only found 2 resources on line that actually sell these TRV's. Both places look amazingly alike not in just look and feel but price.

They do sell a Macon Brand TRV which does come with a vacum release on the valve but the price is like double the cost of the honeywell.

I also notice that neither of them are selling the honeywell SA123A anymore but now sell the unit with a Hoffman 41.

Bottom line is I'd like to avoid shelling out another $200+ per room to fix this problem. I'll just go back to using air vents due to the fact that this spitting water coming out of my TRV is wrecking my hardwood floor.

I can find an 1/8 inch vacum breaker that I guess will work but now I will need a Tee fitting with one male end to screw into the radiator, one inline female to put the TRV into and then a female fitting at 90 degrees to screw the vacum breaker. Any idea where I could find something like that?

mel rowe

Just happened to notice that this subject was reopened and thought I'd add some more recent info. Based on the contention that my water in TRV problem was due to the lack of a vacuum breaker in the TRV, I bought a Macon TRV and tried it in the location that has the worst problem. It made no difference at all. As I mentioned in a different post, the only thing that has really helped with my problem is downfiring my boiler to reduce the velocity of the steam and to better match the attached EDR of my system. AS I understand it, this produces drier steam and less water throughout the system.

Paul Pollets

Danfoss RA2000-1PS

Try the Danfoss RA2000-1ps valve (#013G0140) valve body, The TRV head (#013G8200) and an air vent (013L8300)

This will fix it.


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mel rowe

Thanks Paul. I read on this site previously that both the Macon and the Danfoss TRV's, which both have vacuum breakers, should solve the problem. Why is the Danfoss likely to fix it when the Macon did not?

Paul Pollets

Danfoss

I've used hundreds of Danfoss valves, never the Macon. I refer products that I know work, and whose products are widely available.

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JimH

wrong thermostatic valve

this is a common problem. many mechanical companies often make this mistake . they use thermostatic valves intended for two pipe systems on a one pipe system. you need to get the correct valve for a one pipe system and replace the other thermostatic valves. i know it is a lot of work, but it is the only way to fix this problem. you are trapping condensate as soon as the thermostatic valve senses the temperature drop.

mel rowe

Well, this whole thing is really a puzzle. I've had Honeywell TRVs for several years now. Not a problem last year. Over the summer I fixed my near boiler piping, going from one two inch pipe out of the boiler to a drop header with two two inch tappings out of the boiler. I expected this would cut the velocity in half. Now I wonder if the steam was so constrained previously that the velocity was actually slower than it is now? At any rate, I have a few locations where the TRV is very prone to collecting water. Both the Honeywell and the Macon TRVs are for one pipe systems and the Macon has a built in vacuum breaker, yet it still had the water problem. I'm really lost here. Thanks.

ttekushan_3

Hi mel,

I feel your pain.

The near boiler piping change you made reduces the steam's exit velocity from the boiler itself. Very good idea. But the drier steam in the system may have a higher velocity as you surmise. But this shouldn't cause a problem. It could unmask one, though.

You mention the Gorton main vents. Were these changed at the same time? Say you had the reliable yet hopelessly dinky Hoffman 4A main vents. The air would be forced to re-enter through the radiator vents, perhaps clearing the water from the TRVs. This too could mask the problem.

And Hoffman radiator vents and others with the float operation seem more prone to trouble than the gorton or cheapie maid-o-mist vents.

So here comes the fun (!?) part. I've tuned two steam heating systems in succession this last week with the same problem you (and others!) describe. Then something struck me.

See if there are any similarities to your set-up:

Both systems are single pipe. Both systems drip at the end of main into the wet return. Neither system has dripped vertical risers (remember this factoid). Both buildings are two story. Pressure reduction made no difference. Firing rate made no difference (within bounds of reason). The problem radiators in each case are BOTH taken off mid way along the main AND on the second floor, surrounded on the main by a few large first floor radiators. And each one is the LAST second floor radiator on the line. The main's pitch towards the wet return seems minimal too.

There's probably a chorus of the Dead Men saying, "why do you think we bothered to drip risers in the first place?"

I suspect that area doesn't drain well and may be susceptible to condensate carryover (carryup?) from the main or shared radiators on the riser. Therefore the steam reaching the problem radiators is more turbulent with entrained water and air.

I'm picturing a main that at its starting point has higher steam velocity due to the whole of the connected load on it, but with little collected condensate. At its end, the steam velocity is low due to diminished load, but condensate falling into the return at a pretty good clip. Now the middle. Slower steam velocity, and somewhat slower but substantial condensate load given the dimensions, length and pitch of the pipe.

I'm thinking the riser is stacking up with droplets of water, and its showing up higher in altitude because of the condensate load of the first floor radiators. Closure of a trv or vent pretty much stops the process, but the damage is already done.

In my case the valve sizes on the radiators are the same, so thats not it either.

In the coal days the designers figured that they could get away with it. Your formerly screwed up piping had a similar masking effect. And your lousy venting kept the main from filling too quickly. And the re-entry of air has many paths of least resistance now.

In the short term I stuck a maid-o-mist vent on the problem rads (thats what they sell in these parts, other than the Hoffman). No float or tongue, so they don't hold water well.

You want a solution, don't you. I don't have one yet. One thought is to nudge the radiator over and eliminate the angle globe valve and install an elbow and gate valve. This should reduce turbulence. I'm also thinking that a small baffle plate in the horizontal line, open at the top and bottom but tilted with the top edge leaning in the direction of the steam flow would act as a steam separator (picture a butterfly valve with the top and bottom edges cut flat).

I may not be able to experiment with this myself since the property owner is perfectly satisfied with the current but imperfect solution. Believe me, these systems were so bad, the wet vent issues weren't even on the list of symptoms.

Any other ideas out there? I hope this is helpful in visualizing whats probably going on, but I don't want to send you on a wild goose chase based on my impressions and not by experienced solutions.

-Terry

mel rowe

Thanks Terry for taking so much of your time to respond. Just a couple of points of info. With my oversized boiler, even with the second tapping, the velocity just dropped from 54 ft/sec to 27, which is still far too high, but there is nothing further I can do. I made sure the risers to the header were as high as possible (34 in.) to minimize water being carried out. I've had the Honeywell TRVs and Gorton main vents for two seasons now. So the only change that seemed to trigger my problem was the near boiler piping change. One similarity to yours is that the worst problems occur on rads on the second floor in areas that I know have minimal pitch on the runouts to the rads. The only things that have helped are installing a Vaporstat and setting the cutout at 8 oz. and downfiring my big boiler to the real attached load. This took me from a gas flow of about 5.1 cu. ft. /min. to about 3.8. When I get back home I will try the suggested Danfoss valves, and perhaps also try using a slow venting valve on top of the TRV. Will feed back results later. Thanks again to all.

Steamhead (in transit)

You might have something there, Terry

I assume all the pipes were insulated?

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ttekushan_3

yup.

all the pipes are insulated. Sigh.

ttekushan_3

yup.

all the pipes are insulated. Sigh.

ttekushan_3

yup.

all the pipes are insulated. Sigh.

ttekushan_3

yup.

all the pipes are insulated. Sigh.

ttekushan_3

really. Once was enough.

the page was frozen, and I reloaded. I know I can be repetitive but...

I had no idea that stopping the page loading and reloading would have this effect.

ttekushan_3

I think

you're generating quality steam, but its getting enwettified (don't bother looking up that word) as it cools against the condensate flow at or just below the troublesome radiator.

The other vents may be your best bet, and thanks for letting us know.

-Terry

gerry gill

bingo

you got it melrowe..

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gerry gill

bingo

must have a heavy finger today.

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t.p.tunstall

one pipe steam trv

danfoss and macon recommend an off cycle to let air back in the system to let the condensate back just as bb mentioned in his post