Never saw this before- Baffled!

[joemach]

So I did a maintenance on a hot water oil boiler. All tuned it up and was running clean & great.

Pressure 12 psi cold 14-15 when running.

Just before leaving I check the auto air bleeder and push the schrader valve in and release a bunch of air. Now I can't get the pressure above 4 psi. Cold or running even just the pump (has domestic). The pressure will not move.

Here are some pics of the fill regulator. Never say this before either.

What the heck did I do wrong here. Not cold enough for heat just yet so no big deal right now, domestic is fine at 60 psi. So he can use that.

I am at a real loss here as to what the heck is going on.

I put a separate gauge on one of the drain valves and confirmed the pressure at around 5 psi.

That thing below the air scoop is the regulator. Do they ever go bad? I see no way to adjust.

I did a power purge and I did see it fill so I have no idea what is going on here.

[pageyjim]

The "extrol" tank pressure controls the system pressure. What was the air pressure in the tank? The tank should be isolated to properly check. I believe it has a removable strainer also. I imagine the check valve could be stuck. I forget without one in front of me if it has an external adjustment.

I don't see how a proper maintenance could have been done if it was so low on water. (Since you only let air out acc. to your post.) JS

[pageyjim]

The Amtrol filtrol comes as a set with the tank and autofill. I would change the air vent while you are at it. Does it have a LWCO? Good time to consider that while you have the system open. I assume the system is shut down in this unsafe low water condition.

[Metalman0880]

That’s way old style. Better off replacing the tank and fill valve with a newer style FB 38. And if the tank is bad, you can’t just replace the tank.


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[joemach]

The "extrol" tank pressure controls the system pressure. What was the air pressure in the tank? The tank should be isolated to properly check. I believe it has a removable strainer also. I imagine the check valve could be stuck. I forget without one in front of me if it has an external adjustment.

I don't see how a proper maintenance could have been done if it was so low on water. (Since you only let air out acc. to your post.) JS

I did not have an air gauge to check the air pressure in the tank. Going back tomorrow with a good one. First boiler of the season and need to get my boiler tools all together.

While doing the maintenance the pressure in the boiler maintained 14-15 psi while running and escribed in my first post. The boiler pressure only dropped after I released some air. I don't get it either. Makes no sense.

[joemach]

That’s way old style. Better off replacing the tank and fill valve with a newer style FB 38. And if the tank is bad, you can’t just replace the tank.


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When I did a power purge on the whole system, new water did come into the boiler.

[pageyjim]

I did not have an air gauge to check the air pressure in the tank. Going back tomorrow with a good one. First boiler of the season and need to get my boiler tools all together.

While doing the maintenance the pressure in the boiler maintained 14-15 psi while running and escribed in my first post. The boiler pressure only dropped after I released some air. I don't get it either. Makes no sense.

I suggested to replace the same with same bc it would be much easier and quicker and less costly than having to repipe anything. Also people can get themselves in "trouble" with a homeowner by saying everything is all right then something happens at the last minute like it seemed to on this call. I was assuming that could have happened. Upgrading to a more modern auto fill is of course better to do.

I meant that a proper maintenance couldn't have been done because I couldn't imagine the baseboard or radiators all getting hot being low on water. You could tell that even by being downstairs because the boiler temp would raise quickly and not lower when the burner is off and the pump running.

[joemach]

I suggested to replace the same with same bc it would be much easier and quicker and less costly than having to repipe anything. Also people can get themselves in "trouble" with a homeowner by saying everything is all right then something happens at the last minute like it seemed to on this call. I was assuming that could have happened. Upgrading to a more modern auto fill is of course better to do.

I meant that a proper maintenance couldn't have been done because I couldn't imagine the baseboard or radiators all getting hot being low on water. You could tell that even by being downstairs because the boiler temp would raise quickly and not lower when the burner is off and the pump running.

Jim,

This is what is so confusing to me. All radiators were getting hot and operating as normal until I drained some for the air from the air bleeder. The temp in the boiler did not rise quickly at all. Somewhat close to what I would expect.

Now that I think about it, I wonder if this is just a slow fill valve. I have seen them fill very slowly when do a purge on the system. Guess I will see tomorrow.

[pageyjim]

Jim,

This is what is so confusing to me. All radiators were getting hot and operating as normal until I drained some for the air from the air bleeder. The temp in the boiler did not rise quickly at all. Somewhat close to what I would expect.

Now that I think about it, I wonder if this is just a slow fill valve. I have seen them fill very slowly when do a purge on the system. Guess I will see tomorrow.

Sorry that I assumed too much. Yeah that doesn't make much sense to me either then. Good luck. Love to hear how it turns out.

[Metalman0880]

Jim,

This is what is so confusing to me. All radiators were getting hot and operating as normal until I drained some for the air from the air bleeder. The temp in the boiler did not rise quickly at all. Somewhat close to what I would expect.

Now that I think about it, I wonder if this is just a slow fill valve. I have seen them fill very slowly when do a purge on the system. Guess I will see tomorrow.

Couple of things I’d be looking at.

Possible you have a bad tridicator. Possible your filling slow and valve is failing or you have a restriction in the water feed line. I see copper, is it galvanized upstream?

Those are pretty simple to replace. Galvanized close nipple and tee. 3 male adapters and your off to the races.

Tap on the tank with something metallic. If it doesn’t feel hollow, your tank is waterlogged and the bladder inside has burst.


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[pecmsg]

I did not have an air gauge to check the air pressure in the tank. Going back tomorrow with a good one. First boiler of the season and need to get my boiler tools all together.

While doing the maintenance the pressure in the boiler maintained 14-15 psi while running and escribed in my first post. The boiler pressure only dropped after I released some air. I don't get it either. Makes no sense.

You have gauges don't you?

[pageyjim]

Couple of things I’d be looking at.

Possible you have a bad tridicator. Possible your filling slow and valve is failing or you have a restriction in the water feed line. I see copper, is it galvanized upstream?

Those are pretty simple to replace. Galvanized close nipple and tee. 3 male adapters and your off to the races.

Tap on the tank with something metallic. If it doesn’t feel hollow, your tank is waterlogged and the bladder inside has burst.


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He double checked and confirmed low pressure condition at a drain valve.

[icy78]

First thing to do is pull that expansion tank and check its condition. If water comes out of the Schrader it is shot. If water does not come out it's probably just leaked air through its membrane and you can recharge it. That is something that happens at a slow rate every year.
I would change the fill valve while at tank is off and yes they do fill slowly. The tank pressure controls the system and that needs to be set up right first.
If the pressure dropped to 4 PSI that is more than likely not enough pressure now to get to the top of the radiators on the second floor and maybe not on the first floor.

Also the pump needs to be pumping away from the pressure tank /fill, and towards the rads.

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[pageyjim]

First thing to do is pull that expansion tank and check its condition. If water comes out of the Schrader it is shot. If water does not come out it's probably just leaked air through its membrane and you can recharge it. That is something that happens at a slow rate every year.
I would change the fill valve while at tank is off and yes they do fill slowly. The tank pressure controls the system and that needs to be set up right first.
If the pressure dropped to 4 PSI that is more than likely not enough pressure now to get to the top of the radiators on the second floor and maybe not on the first floor.

Also the pump needs to be pumping away from the pressure tank /fill, and towards the rads.

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Good advice but replace them both while you are there along with the air vent. I assume the homeowner had heat last year. It is normal to lose app 1 lb of pressure or so/year. If this is 4-5 lbs psi then it is ready to go. It will be less expensive to do it together and the homeowner would only get upset after paying for a repair only to have another one possibly happen. The air vent was either closed or not working so that should be replaced too.

To the OP forgot to ask if there was a backflow preventer installed already. Always good to mention it at least

[joemach]

First thing to do is pull that expansion tank and check its condition. If water comes out of the Schrader it is shot. If water does not come out it's probably just leaked air through its membrane and you can recharge it. That is something that happens at a slow rate every year.
I would change the fill valve while at tank is off and yes they do fill slowly. The tank pressure controls the system and that needs to be set up right first.
If the pressure dropped to 4 PSI that is more than likely not enough pressure now to get to the top of the radiators on the second floor and maybe not on the first floor.

Also the pump needs to be pumping away from the pressure tank /fill, and towards the rads.

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Checked the tank and no water came out, only air. Found out the expansion tank only had 4 psi. Pumped it up to 12 and all is good again.

Just don't understand how bleeding off a little air from the auto bleeder caused this whole issue.

This is a 50 year old boiler (oldest I have see).

[icy78]

I think what happened here is that your tank pressure, unbeknownst to you was only at 4 PSI. Your system pressure was 12 to 14 PSI. But that pressure included the air trapped in the system. Then when you let that trapped air out, the system pressure dropped to 4 PSI. If the fill valve is not filling the tank then it would stay at 4 PSI and probably not circulate properly to the high points. Then when the pressure had come back up, assuming now a good fill valve, the room for expansion in that system would have been very small , and there's a good chance the relief would have blown especially later on this year when that old boiler will likely be putting out 210 degree water .

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[joemach]

I think what happened here is that your tank pressure, unbeknownst to you was only at 4 PSI. Your system pressure was 12 to 14 PSI. But that pressure included the air trapped in the system. Then when you let that trapped air out, the system pressure dropped to 4 PSI. If the fill valve is not filling the tank then it would stay at 4 PSI and probably not circulate properly to the high points. Then when the pressure had come back up, assuming now a good fill valve, the room for expansion in that system would have been very small , and there's a good chance the relief would have blown especially later on this year when that old boiler will likely be putting out 210 degree water .

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Thanks Icy. That makes sense.

How ever I am still somewhat baffled to understand how only having 4 psi in the expansion tank would not all the fill valve to allow the boiler to fill to 12-14 psi. It seems counter-intuitive to me. I am still trying to get my head around this and how it san operate this way. It may have something to do with this old style fill valve (which does now seem to be operating correctly).

[servicefitter]

Don't see a water regulating valve just a gate valve if thats what u have the gate valve is broke gate. Ex tank will not stop a fill valve from filling.

[pageyjim]

Don't see a water regulating valve just a gate valve if thats what u have the gate valve is broke gate. Ex tank will not stop a fill valve from filling.

No it has one it is an Amtrol Filtrol.

[servicefitter]

Don't see a water regulating valve just a gate valve if thats what u have the gate valve is broke gate. Ex tank will not stop a fill valve from filling.