Safe to close balancing valves over the summer?

jace_in_nh

I have an oil-burning boiler system with two baseboard heating zones and an indirect water heater for DHW. Recently I'm experiencing a lot of ghost flow heating going to parts of both baseboard heating zones, first and second floor. The only zone calling for heat is the indirect water heater, yet my DHW never heats up because it seems most of the heat is being diverted to the two baseboard heating zones. I have Taco 219 Swetcheks on the supply side of each zone, but they do not seem to be stopping the ghost flow. I have circulator pumps on the return side of all three zones and before each of the two baseboard heating zone circulator pumps, each pipe has a Watts PB-56 Purge and Balancing Valve. I closed the balancing valves just the other day when I was bleeding each zone and that worked great, but is closing the balancing valves helpful (and safe) for trying to solve the ghost flow problem? I don't need heat on either floor right now, but I do still want DHW.

Jamie Hall

Sure. That will work fine. It won't solve the underlying ghost flow problem, but it will do what you need for the summer.

A suggestion: mark where the balancing valves are set to now. Save you a lot of grief next fall...

STEVEusaPA

I'd turn of the thermostats too. One cool night and you could deadhead a circulator.

jace_in_nh

Jamie Hall said:

Sure. That will work fine. It won't solve the underlying ghost flow problem, but it will do what you need for the summer.

A suggestion: mark where the balancing valves are set to now. Save you a lot of grief next fall...

Yeah, I know I will need to actually get the problem solved, but in the short term I'm just trying to deal with having the baseboard heaters heat up when it's already 70 degrees out. And hopefully still have hot water while I'm at it.

And the balancing valves are set to fully open right now, parallel to the pipe direction.

jace_in_nh

STEVEusaPA said:

I'd turn of the thermostats too. One cool night and you could deadhead a circulator.

The thermostats are both off right now, unfortunately that wasn't keeping the ghost flow from heating up sections of the baseboard heaters on both floors. One of those sections being my bedroom, so that could get pretty miserable as it warms up.

mattmia2

Do the flow checks by any chance have manual levers that have been left in the open position?

jace_in_nh

mattmia2 said:

Do the flow checks by any chance have manual levers that have been left in the open position?

They have a thumbscrew at the top that can manually open them, but none of them are manually open. I've attached an image of what they look like. I really have no idea why they aren't stopping the hot water from flowing into the baseboard heating pipes. Both the first and second floor are getting ghost flow heat in sections and it seems unlikely to me that they would both fail around the same time.

jace_in_nh

Just an update here. I had turned off the boiler for a couple of days, because the ghost flow heating combined with the warm weather was making some rooms unbearably hot (including my bedroom). The downside there being that I had no hot water either, since I have an indirect water heater for DHW. Today I turned the boiler back on, but I closed the two balancing valves for the 1st and 2nd floor heating zones, leaving the valve for the indirect water heater open. I kept an eye on it and the boiler pressure seems fine, thankfully. Hot water still started to go to the 1st and 2nd floor heating circuits, but my hope is that with the return balancing valve closed, the whole convection loop won't be able to continue. Some water will go to the heaters but it will cool and new hot water from the boiler won't be able to replace it. I'm hoping that the boiler will continue to feed the only circuit still open to it: the indirect water heater for DHW.

But I'm still learning a lot here. Does my theory make sense?

Dave H_2

Technically yes, you don't have the "loop" to facilitate the gravity flow but it can still happen. Hot water rising and cold water falling in the same pipe can occur.
I do have one question though, has anything changed at all in the system? Circulator change, component replacement...you said you were purging the system? Why?

jace_in_nh

Dave H_2 said:

Technically yes, you don't have the "loop" to facilitate the gravity flow but it can still happen. Hot water rising and cold water falling in the same pipe can occur.
I do have one question though, has anything changed at all in the system? Circulator change, component replacement...you said you were purging the system? Why?

No components have changed yet. I purged the system because I was getting a lot of this ghost flow problem and I was hearing a lot of air in the pipes (sometimes quite loud). When I purged the system, I got a lot of air out and the water was initially really murky. And the day after I purged the system, everything seemed to be working perfectly well again, then the ghost flow came back.

There is corrosion on the boiler near the Honeywell aquastat that went unnoticed for some time and the boiler does run a bit too hot right now. I suspect maybe the boiler running too hot pushes the water into the heating zone circuits past the flow check valves that would normally stop it.

EdTheHeaterMan

Did you check the FloCheck (Sweat Check) valve thumb screw?

Think of that thumbscrew as either OPEN or AUTOMATIC. You want it on AUTOMATIC or completely closed (unless a circulator opens it).

Here is a test you can do...
if a Flo Check valve is working properly, the hot water may reach the valve by gravity or ghost flow. If the valve is closed completely the outlet side of the pipe should be much cooler. You should be able to feel the pipe a foot away from the flo check and there should be no heat. If the pipe is just as hot on both sides of the flo check valve, then the valve is open.

See if the thumb screen will move... open it and then close it... check the pipe temperature in one hour to see if there is a temperature difference. The outlet should be much cooler. If there is no difference, then you need to repair or replace the flo check valve(s) or see if the circulator is rynning.

To more fully understand what that valve is doing read column 2 on page 9 of this book. The valve is the book is made by another company but it is essentially the same thing. That company called their valve "Flow Control" valves while TACO calls them Flo Check or Sweat Check.
http://media.blueridgecompany.com/documents/ZoningMadeEasy.pdf

If this is a new problem then something has changed to cause the problem.

One other thing you mentioned is that the boiler "runs a bit too hot right now". This implies that the boiler was running cooler in the past. Two things come to mind. #1 is a heat zone circulator be operating even though there is no call for heat. That could be a problem with the relay that operates that circulator. #2 could the high limit control on the boiler be a problem? if there is a closed (welded/burned together) contact on that control, then the boiler is overheating and if the water is near boiling temperature you would hear that and that may cause the flo valve to pop open intermittently to let off some pressure to the other side of the flo valve.

After the water heater is up to temperature the burner should stop and the boiler should go cold. If your boiler is always hot, then there is a control that is keeping the burner ON somewhere

If you are not comfortable with or qualified to determine that, It may be cheaper to hire a pro to solve the problem. All that fuel wasted from a defective control isn't free.

Hope this information is helpful.

Respectfully submitted,
Mr.Ed

jace_in_nh

EdTheHeaterMan said:

Did you check the FloCheck (Sweat Check) valve thumb screw?

I have three Taco 219 swet-chek valves, one for each floor of baseboard heaters and one for the indirect water heater supply line. I'm not a huge fan of how the indirect water heater installers did this, because the supply pipe from the boiler first branches off to a pipe with a swet-chek valve that feeds the first floor baseboard heaters, then a few inches down the supply pipe it branches off to the indirect water heater supply, and then it continues to go to the second floor baseboard heating. I would have preferred that the DHW supply be the first branch in the supply line, personally, rather than sitting between two baseboard heating zones.

The pipe on both sides of all three valves is hot. The thumbscrews are not open. I did briefly open the swet-chek valve manually for the second floor heating zone the other day just to make sure it would open and then I closed it again.

My guess here is that the boiler, because it is running a bit hot, is pushing this water through with more pressure than standard. The swet-chek valves are designed to open when the water is coming through with enough force (usually created by the circulator pump). I think in this case the overheated water might just have enough force on its own to open the valves.

jace_in_nh

EdTheHeaterMan said:

To more fully understand what that valve is doing read column 2 on page 9 of this book. The valve is the book is made by another company but it is essentially the same thing. That company called their valve "Flow Control" valves while TACO calls them Flo Check or Sweat Check.
http://media.blueridgecompany.com/documents/ZoningMadeEasy.pdf

Thank you for the document, though. I'm going to read through that, because I've been trying to learn as much as I can about how this all works.

EdTheHeaterMan

Why is the boiler water hotter than usual?

jace_in_nh

EdTheHeaterMan said:

Why is the boiler water hotter than usual?

I'm not certain, but I think it might be something like #2 that you mentioned above. There is corrosion on the boiler where the aquastat is mounted and where the immersion well for the temperature probe goes. I haven't gotten a good look at the inside of the aquastat itself yet (and if it has a high limit setting that I can set) because the corrosion has the outer case sticking on.

The boiler doesn't constantly stay on, but I do think it is going on more than it needs to, which you're right, is a waste of heating oil. I do want to have someone come out and look at it soon, I'm just hoping to see if I can get DHW without also heating my rooms in the meantime.

EdTheHeaterMan

Your piping description is a little ambiguous. When I first read your description, this is what I pictured.

Then I read it two more times and I believe this is what you are describing.


The second diagram should be fine.

From your description, I believe you may have a control problem that is keeping the burner on when there is no call for heat.

BTW. when @STEVEusaPA mentioned you should turn off the zone thermostats, it was to keep the circulator from operating against a close valve. That is called deadheading. If you forget to set the thermostats OFF, then a cold night could make the thermostat operate the pump without you being aware and maybe causing the circulator pump to fail.

jace_in_nh

The second diagram is correct. And it does work; it has in the past, but I honestly wish I had an isolation valve or two where I could just block off the heating while still feeding to the DHW. The swet-chek valves are supposed to do effectively that, but they aren't a manual isolation valve that I can close.

And my zone thermostats are off. One of them (2nd floor) is entirely off of the wall right now. The first floor one is turned all the way down and I have not seen it call for heat. Another design criticism I have is that my first floor thermostat and my indirect water heater feed into a Taco SR503 switching relay and the zones light up if they are calling for heat. My 2nd floor thermostat appears to be wired to the Honeywell aquastat attached to the boiler (even though I have an open third relay switch on the SR503) and I can't see any indication if it is calling for heat and my Taco circulator pumps run so quiet that it's hard to tell when they are on. So I took that thermostat off of the wall entirely for now.

mattmia2

This really sounds like a control problem. Maybe there is a control wire touching something it shouldn't, or maybe controls are cascaded in such a way that something is stuck but only shows up if the DHW is calling.

The leak at the aquastat on the boiler that is all crusty may be letting enough fresh water in that you are having issues with the dissolved air that comes out of that water as it is heated the first few times.

Dave H_2

The "hotter" water will not increase the buoyancy that much in order to open a SwetChek, they have a high opening pressure that will open when a circulator runs.
However, one note you told me is that the water is very dirty, The weight (check) rides along a shaft (up and down) and if it can't move smoothly, then it may be getting hung up and not settling back into place. It could also deposit on the seat therefore preventing it from closing all the way.
You could take it apart and inspect. If cleaning works, then you are good to go.
If it can't or shouldnt be cleaned, there are replacement parts available

jace_in_nh

Dave H_2 said:

The "hotter" water will not increase the buoyancy that much in order to open a SwetChek, they have a high opening pressure that will open when a circulator runs.
However, one note you told me is that the water is very dirty, The weight (check) rides along a shaft (up and down) and if it can't move smoothly, then it may be getting hung up and not settling back into place. It could also deposit on the seat therefore preventing it from closing all the way.
You could take it apart and inspect. If cleaning works, then you are good to go.
If it can't or shouldnt be cleaned, there are replacement parts available

The water was very dirty, yes. I bled/purged all of the zones last Sunday until all of the air was out and the water was clean. But there could still be something stuck in these valves. I'm not clear how the SwetChek valve comes apart. If I continue to loosen the knob on the top, will that eventually remove these pieces for cleaning? Or is there another part of it that I have to loosen to get it apart?

Dave H_2

The knob will only go so far and stop. In order to take it apart (make sure boiler is cold and pressure is reduced to zero) and use a 1-1/4 wrench to loosen the assembly at the cap