Boiler heating problem

nd_alex

Hydro-Therm natural gas fired boiler.



100 y.o. 2-story home, cast-iron radiators. Boiler is in the basement, lot of vertical rise.



For the last couple of days (this problem has just started), we wake up in the morning to a 66 degree house, even though the thermostat is set at 70 degrees. Battery in the thermostat is new. Weather has been very mild, only in the 30s at night. Checked the tridicator, water temp was at 200 degrees or so, but pressure was below 5 lbs. Added water. Pressure got up to about 30. House started warming up. Came home that evening to find water in the bucket under the 30 psi high-pressure release pipe.



The next morning, same thing.



It's acting like it's 30 degrees below out, rather than 30 above.



What could be the problem?



TIA



Alex

Jamie Hall

Expansion tank

lost air charge... what to do depends on the kind of tank you have.  Need a little more detail...

nd_alex

Expansion tank

Well, there are two expansion tanks, each slightly larger than a 20 lb. propane tank, right next to the boiler. They are connected together, and there is a "tee" fitting between them, that is connected into the main piping near the ceiling of the basement, with a valve in-line (the valve is open). Both tanks are cool to the touch, but near the top of the feed pipe it is warm. The tanks have "reflex" printed on the top of them. It looks like they have a Schrader valve on them, but if that is what they are, I can't remove the cap by hand, and I am worried about trying to use a tool on the caps to remove them, until I know for sure they are indeed caps.



Does that help?

Steve Whitbeck

tank pressure

Drop the boiler pressure to o and check the air pressure in both tanks - it should be 12 PSI. If there isn't any air in the tanks and you get some water out of the schreader valve then the tank has to be replaced. If no water comes out you can try just putting air in.

As you add air have the relief valve propped open to let the water out that the air is going to push out of the tank. The goal is to have all of the water out of the tank and 12 PSI of air in the tank.

kcopp

Sounds more like....

a circulator issue than a expansion tank issue. How many zones? If its just one zone you could be getting gravity flow.... just enough to give you some heat, just not a lot of heat.

Paul48

?

Those expansion tanks may be charged with nitrogen?

STEVEusaPA

I'd go with kcopp

The original post said he had 200 degree water and no heat. Most likely shut off on high limit because the water wasnt circulating. The high pressure issue only came up when he added water. Get a pro over there to check out your system.

nd_alex

Heat

Just to clarify, on the mornings that we had the problem, the main floor radiators were warm (not hot), and the second-floor radiators were cold... Now, last night, the temperature maintained at the setting that I chose before bed, even though I haven't done anything or changed anything. So this seems to be kind of an intermittent problem?

kcopp

I still think...

Its a circulation issue. May be a bad relay. Sometime they get a little funky and don't always turn on.

nd_alex

power

Ahhh.... I'll start testing with a voltmeter during a heating cycle, see if power is getting to the pump...

nd_alex

Tanks

I decided to troubleshoot the tanks too, even though the latest advice is pump. Lo and behold, no pressure in the bladders. So, I try to pump them up... Nope. No go. So, I remove them from the system, and drain them. Still not able to pump them up. Remove the valve stems - same problem.



Is it possible the bladder is now a pancake, and the opening is now fused together? I suppose that could happen after enough time has elapsed. I have never checked them before, so they may have been like this for a while now.



Any ideas? Any advice on where to purchase, what brand, whether I need two or just one, etc?



TIA

ChasMan

Hate to state the obvious...

Buy a new tank? The pressure should be checked every year. At least every two. The drop a pound or so a year. Well, at least mine do.

ChasMan

Tanks.

The size and quantity of tanks you need is based on the volume of water in your system, the static fill pressure, and the temperature rise, and the desired pressure you want after you heat the water up.

The pressure you need depends on the amount of lift you need. You can get tanks anywhere, there are several makes but folks seem partial to Amtrol. I have an Amtrol tank. Two actually, they are both oversized. You cn;t have too big of a tank. It makes setting the pressure much easier with great big tanks. But you don;t need too big of  a tank. You can download tanks software from some manufacturers sites. I think Amtrol has a chart. If you don;t know how much water is in your system you can guesstimate by looking up your boilers specs, your water heater's specs, and then measuring all your pipes. One thing you can do if you oversize your tanks is to raise the static fill pressure to whatever you want because heating the water up won't raise the pressure. 2 stories = 12 PSI static in most cases but with a regular tank it might go to 17 or more when the water heats up.