Gravity Feeding

My EFM has been running since October 5, 2008. It has been only shut down for cleaning and the installation of my DHW coil last May. During the summer myfirst floor zone has been gravity feeding. This wasn't a problem last year so I thought maybe the flow check valve was broke. I opened it, banged on it and re-closed it with no results. I closed the valve for the zone at the circulator pump which stopped the problem. I was going to change out the flow check valve but now the second floor radiators are getting hot. The upstairs is getting up to 74 when the tstat is set at 60. I was keeping the aquastat at 150 low, 190 high because of the DHW (probably a mistake). I turned the low on the aquastat down to 140, high 180. Could the boiler water just be to hot for this time of year or am I looking at two broken flow check valves? I somehow can't see two valves failing within such a short period of time. Any thoughts?

Whatever the problem is you just pushed it to the other zone by cutting off the first floor zone...
Now the heat just finds the other open zone and rises up to the second floor to release the heat, then fall back down...
Just close the other zone valve...
And kill the circulator pump...
She no like closed valves...
Flow check valve just keeps water from falling back.
If there is enough pressure from the hot water it will push it open...
And warm you unnecessarily

Thanks, from what you're saying I think I created my own problem by keeping the boiler so hot. Boiler pressure was up to 20lb with the aquastat set at 150 forcing the water through the radiators. I cut off both zones for tonight. Once the boiler temp drops I'll open the valves and see what happens. I was running the temp that high for hot water not realizing all I have to do if the hot water gets to cold is adjust the mixing valve. Hopefully this is only a balancing act that I messed up and not anything more serious. I don't have time for another project right now. I have my living room torn apart putting wainscoting and a new banister in. If it's not done by my daughter's wedding in December I may as well build a dog house cause that's where I'll be for the next decade. Thanks again.

The 'rents oil boiler was set higher than that...
before I got ahold of it.
They never had any self circulating issues.
I don't think it is your temps that are causing the problem.
How tall is the house, 20 psi seems a bit high for 2 story house.
Finish the walls and open the window or you will find out how cold it can really get!

like you stated the idea of two flow checks going bad makes no sense as far as pressure goes you need 1# of pressure for 27" of altitude or 2.31' x press = altitude or height of h2o in feet .i have seen circ problems because of press especially on monoflow systems so I guess excessive press could exaserbate an existing problem you could feel the pipe with your hand working backwards to find out where the heat is migrating from there has to be a connection somewhere that is allowing a bypass or your circ is running periodically

It's a two story house. The boiler is in the basement so the second floor zone is about 15 feet above the boiler. The water temp dropped and now the pressure is around 13 lb. The pipe for the first floor zone is lukewarm and all others are cold. I guess I can live with it for now but I'd sure like to know the cause. The weird thing is I have a zone in the basement/workshop that isn't being effected. It's dead cold and it's on the same level as the boiler.

billw wrote:It's a two story house. The boiler is in the basement so the second floor zone is about 15 feet above the boiler. The water temp dropped and now the pressure is around 13 lb. The pipe for the first floor zone is lukewarm and all others are cold. I guess I can live with it for now but I'd sure like to know the cause. The weird thing is I have a zone in the basement/workshop that isn't being effected. It's dead cold and it's on the same level as the boiler.

The pressure should not change that much. Check your air tank and drain it to recharge with air, if you have one, or if you have the type with a bladder perhaps it is bad.

The workshop zone is too low to gravity feed readily.

Richard

Thanks Richard. I have the bladder type, actually two, one near the oil unit that was installed in 94 and the other near the coal unit installed last year. The boilers are series connected. Lowering the water temp didn't really change anything. Yesterday both first and second floor zones were gravity feeding. I did learn that the water flow is the same direction as if the circulator was on. Supply side of the zone gets warm first followed by the return. For now I'm turning both zones off and living with it cause I'm up to my ass in aligators. Hopefully Monday I'll have the chance to take a look. How do I know if the tank is bad?

billw wrote:Thanks Richard. I have the bladder type, actually two, one near the oil unit that was installed in 94 and the other near the coal unit installed last year. The boilers are series connected. Lowering the water temp didn't really change anything. Yesterday both first and second floor zones were gravity feeding. I did learn that the water flow is the same direction as if the circulator was on. Supply side of the zone gets warm first followed by the return. For now I'm turning both zones off and living with it cause I'm up to my ass in aligators. Hopefully Monday I'll have the chance to take a look. How do I know if the tank is bad?

I would go by the behavior. If a tank is full of water then any rise in temperature will rapidly cause the pressure to rise to 30 and start to bleed out of the pressure relief valve. As long as that is not happening I would not be concerned. Pressure only needs to be high enough to raise the water to the highest points of the system. It has nothing to do with pushing past the flow control since in a closed system the pressure is equal on both sides. The only thing I have seen that pushes water past the flow control is if the heat is high enough to cause steam, which will push past the control. If that happens though you will hear it as a rattling sound coming from the flow control. I would bite the bullet and take one of those flow valves off so you can see the seat and judge condition. Hard water over the years could make the seal bad. I don't think you can do it in place without damaging your piping, especially if it is copper.

The other thing that caught my eye in your post was the aqua stats. Normally one of them is reverse acting to prevent the circulator from pumping cold water, and the other is the limit control. Older units had three. A reverse set at about 140, a limit set at about 160 to 180 and a high limit set at about 190 to 200. Modern units have all 3 combined into one control. I just wonder if the one you have set at 140 is a reverse and not the controlling aqua stat.

Richard

a couple questions but bear with me....

#1 which side is your flow check on?

#2 which side is your pump on?

#3 is your water pipe hot before the check and hot after, or does it cooler after the check?

#4 is your return pipe hot.

why I ask these questions is because your boiler could gravity flow thru one side if your pipes are large enough, the cool water and hot water can slide past one another of the return or supply. that is one reason I use flow checks on both side on my boiler.

U235a4 wrote:a couple questions but bear with me....

#1 which side is your flow check on?
Flow checks are on the supply side about 4 feet above the boiler

#2 which side is your pump on?
Circulators are on the return side

#3 is your water pipe hot before the check and hot after, or does it cooler after the check?
Pipes are hot on both sides of the flow check.

#4 is your return pipe hot.
Yes, but not as hot as the supply. My oil unit is in series with my coal unit. The oil unit temp goes up over 100 degrees. The oil unit isn't coming on. There is no power to it and no flue connection to the chimney right now.

why I ask these questions is because your boiler could gravity flow thru one side if your pipes are large enough, the cool water and hot water can slide past one another of the return or supply. that is one reason I use flow checks on both side on my boiler.

Today I left both zones open and neither is gravity feeding. I haven't changed anything. Boiler is the same temp, around 140 and it's about the same temp outside as it has been in the last couple of days.

Richard, I have a honeywell triple aquastat. I believe it is an L8124.

what type of flow checks

Watts 2 way. I'm not sure of the model number. They were originally installed in 1995.

Finally figured this out. It was two flow check valves. I reused my old ones from the oil unit when I installed the EFM. Last Saturday I changed the check valve for the first floor and the problem stopped. The second floor is still acting up so I'll be changing it next Saturday. Thanks for the input.