Identify this valve type in a hydronic system (check valve or not?)

[Brad500]

I need to add glycol to my hydronic system. The system does not have purge valves for the various zones. There is a purge valve (not shown) but it is on a common line with the water intake and all 4 zone return lines. The only way I can think to add glycol (or purge air, etc) is by pumping into the bottom drain valve, cycling through each zone and out the common purge valve. But this will only work if I can isolate the bottom drain valve from the water intake upstream of the circ pump. The valve/fixture in question should do this, but I don't know what I'm looking at. Is it a check valve (I can't find an arrow on it)? Or is does that little knob inside a "nut" on the side of the valve need to be turned to close the valve? Or is this fixture something else entirely?

A separate but related question: I also can't figure out how the heck this system was originally filled and purged of air. It has an auto-refill reducer valve but that goes into a common line with all the zone return piping and the only purge valve I can see. So I can't figure out how to force the water to loop from the refill line, through the zones and back to the return line. it can add water to top up pressure just fine, but there is no way I can see for the air to get out and really purge an empty system, except a little auto air ejector on the boiler (and the indirect water heater) and the microbubble ejector with the expansion tank on the boiler outlet side. If I try to fill the system from the auto-refill, I can't open the purge valve that is common with the return lines, because there is no way to force a loop, and the incoming water would just shoot out the purge valve a few feet to the side. Are you meant to fill this setup initially from the boiler drain as I mention above, rather than from the auto-refill line? The system is in a one-story house with in-floor heat (3 zones) plus an indirect water heater.

Many thanks for any help/advice.

 

[GReynolds929]

The circled item is a ball valve with the handle removed. I would guess it is used to throttle the flow and then the handle was removed to prevent tampering.

 

[Brad500]

The circled item is a ball valve with the handle removed. I would guess it is used to throttle the flow and then the handle was removed to prevent tampering.

Thanks!

 

[MicEd69]

GReynolds929 is likely correct. The last picture shows that the ball valve is slightly closed. The hole in the ball is aligned with the two flats on the valve stem where the handle attaches.

 

[Mitchell-DIY-Guy]

I need to add glycol to my hydronic system. The system does not have purge valves for the various zones.

Brad, my experience is limited to the snow melt hydronic system I added to my driveway, back in 2011 or so, and several homes I've lived in (and my father's present home) which have oil fired hydronic systems. This is baseboard radiators.

In the former, the snow melt system, this was a stand-alone and "sealed" system not connected to any water source. I worked with a firm out of Cincinnati called Kost https://kostusa.com/kostchill/ and they blended a 40% glycol solution for me. That provided anti-freeze capability to what I perceived as the worst-case scenario. They blended enough for a 30 gallon drum, and we used 28 gallons to fill the system. My system was designed with central purge and fill lines on the hot and cold sides. The valves were Webstone brand from Supply House. They had garden hose fittings and we filled the system from the drum with a small utility pump. The air eliminator, like most, was at the "top" of the system. Did not seem to have any issues with air in the system. Kost offered a testing service where every few years you drain a few ounces out of the system, send it to them, and they'll blend an additive package to "restore" the system. The plumbing in the system was all PEX, with some copper, copper manifolds, and bronze and stainless pumps so rust was not an issue ever. Sold that house in 2020. I don't think the new owners ever turned on the snow melt system.

In the homes with baseboard heat, all of them were designed probably much like yours. They don't normally contain glycol because it isn't generally necessary in conditioned space. They normally have automatic water re-supply since some of the circulating hot water seems to disappear over time. However, if the conditioned space (such as a vacation home in the mountains) were to be subject to freezing, then for certain you'd need glycol in the system. Surely somewhere on your heater/boiler or system there's a tag from one of the service people and I'd call them to modify your system such that you can easily add a glycol mix. If the home is anywhere near where second homes or vacation homes are, and there is below freezing temps in the winter, those local service folks have experience with what you are trying to do.

There may be some rules about having an automatic water filler connected to a glycol based system, regardless of whether you use PG or EG based glycol. Your local guys will be your best source of information.

 

[Brad500]

I need to add glycol to my hydronic system. The system does not have purge valves for the various zones. There is a purge valve (not shown) but it is on a common line with the water intake and all 4 zone return lines. The only way I can think to add glycol (or purge air, etc) is by pumping into the bottom drain valve, cycling through each zone and out the common purge valve. But this will only work if I can isolate the bottom drain valve from the water intake upstream of the circ pump. The valve/fixture in question should do this, but I don't know what I'm looking at. Is it a check valve (I can't find an arrow on it)? Or is does that little knob inside a "nut" on the side of the valve need to be turned to close the valve? Or is this fixture something else entirely?

A separate but related question: I also can't figure out how the heck this system was originally filled and purged of air. It has an auto-refill reducer valve but that goes into a common line with all the zone return piping and the only purge valve I can see. So I can't figure out how to force the water to loop from the refill line, through the zones and back to the return line. it can add water to top up pressure just fine, but there is no way I can see for the air to get out and really purge an empty system, except a little auto air ejector on the boiler (and the indirect water heater) and the microbubble ejector with the expansion tank on the boiler outlet side. If I try to fill the system from the auto-refill, I can't open the purge valve that is common with the return lines, because there is no way to force a loop, and the incoming water would just shoot out the purge valve a few feet to the side. Are you meant to fill this setup initially from the boiler drain as I mention above, rather than from the auto-refill line? The system is in a one-story house with in-floor heat (3 zones) plus an indirect water heater.

Many thanks for any help/advice.

View attachment 46229


View attachment 46231

Thank

I need to add glycol to my hydronic system. The system does not have purge valves for the various zones. There is a purge valve (not shown) but it is on a common line with the water intake and all 4 zone return lines. The only way I can think to add glycol (or purge air, etc) is by pumping into the bottom drain valve, cycling through each zone and out the common purge valve. But this will only work if I can isolate the bottom drain valve from the water intake upstream of the circ pump. The valve/fixture in question should do this, but I don't know what I'm looking at. Is it a check valve (I can't find an arrow on it)? Or is does that little knob inside a "nut" on the side of the valve need to be turned to close the valve? Or is this fixture something else entirely?

A separate but related question: I also can't figure out how the heck this system was originally filled and purged of air. It has an auto-refill reducer valve but that goes into a common line with all the zone return piping and the only purge valve I can see. So I can't figure out how to force the water to loop from the refill line, through the zones and back to the return line. it can add water to top up pressure just fine, but there is no way I can see for the air to get out and really purge an empty system, except a little auto air ejector on the boiler (and the indirect water heater) and the microbubble ejector with the expansion tank on the boiler outlet side. If I try to fill the system from the auto-refill, I can't open the purge valve that is common with the return lines, because there is no way to force a loop, and the incoming water would just shoot out the purge valve a few feet to the side. Are you meant to fill this setup initially from the boiler drain as I mention above, rather than from the auto-refill line? The system is in a one-story house with in-floor heat (3 zones) plus an indirect water heater.

Many thanks for any help/advice.

View attachment 46229


View attachment 46231

Thanks to everyone for your input. As soon as I saw "ball valve with the handle removed" it clicked in my mind what I was looking at.

But that raises a new question of why that valve on the inlet side of the circ pump would be throttled and why the installer thought it was so important to keep it exactly so that he would remove the handle?

 

[Brad500]

Brad, my experience is limited to the snow melt hydronic system I added to my driveway, back in 2011 or so, and several homes I've lived in (and my father's present home) which have oil fired hydronic systems. This is baseboard radiators.

In the former, the snow melt system, this was a stand-alone and "sealed" system not connected to any water source. I worked with a firm out of Cincinnati called Kost https://kostusa.com/kostchill/ and they blended a 40% glycol solution for me. That provided anti-freeze capability to what I perceived as the worst-case scenario. They blended enough for a 30 gallon drum, and we used 28 gallons to fill the system. My system was designed with central purge and fill lines on the hot and cold sides. The valves were Webstone brand from Supply House. They had garden hose fittings and we filled the system from the drum with a small utility pump. The air eliminator, like most, was at the "top" of the system. Did not seem to have any issues with air in the system. Kost offered a testing service where every few years you drain a few ounces out of the system, send it to them, and they'll blend an additive package to "restore" the system. The plumbing in the system was all PEX, with some copper, copper manifolds, and bronze and stainless pumps so rust was not an issue ever. Sold that house in 2020. I don't think the new owners ever turned on the snow melt system.

In the homes with baseboard heat, all of them were designed probably much like yours. They don't normally contain glycol because it isn't generally necessary in conditioned space. They normally have automatic water re-supply since some of the circulating hot water seems to disappear over time. However, if the conditioned space (such as a vacation home in the mountains) were to be subject to freezing, then for certain you'd need glycol in the system. Surely somewhere on your heater/boiler or system there's a tag from one of the service people and I'd call them to modify your system such that you can easily add a glycol mix. If the home is anywhere near where second homes or vacation homes are, and there is below freezing temps in the winter, those local service folks have experience with what you are trying to do.

There may be some rules about having an automatic water filler connected to a glycol based system, regardless of whether you use PG or EG based glycol. Your local guys will be your best source of information.

Thanks Mitchell - I am definitely in cold country and there should be antifreeze in the system. There are check valves in the auto refill line. I think the system lost a good bit of water/glycol many years ago when there was a leak and it was some time before we got the water cut off. No one at the time mentioned testing the protection level afterwards and I didn't think of it. There have been a couple of different guys out for servicing in the past years and when I mentioned freezing protection they just said it's probably fine. I got the idea they really didn't want to get into it. I did find a useful video online of a guy adding pure glycol to a system and using a 5 gallon bucket as a mixer as he was circulating the mix through the zones. I think I can do something similar now that I know I can simply close that ball valve to create the loop I need when adding glycol. I can't picture any other way that it's possible to push fluid through each zone, actually, and the original installer had to have done it somehow!