Boiler not shutting off. 270 temp 30 degrees pressure help!

[daveswoodhauler]

This is not a wood fired boiler, but I am asking for help as I think we have a problem....was hoping my fellow burners could shed some light.
Boiler kicked on this morning for the heat, and just seemed to run on and on and on....went downstairs to check it out, and the temp was reading 270 degrees, and the pressure was reading 30 psi. (Burnham boiler, forced hot water)
Was thinking that this was not normal, so I shut off the furnace....just didn't want the thing to keep running and had a very quesy feeling.
There are 2 guages on the boiler....temp goes from 0 - 320 and the pressure goes from 0 to 75.
There is a little red arrow on the pressure gauge and seems to be set at 25, so the pressure was over the red mark...was about 30 or 31 when I shut it off. I have lived here 6 years and don't think it has ever been over the red marker.
Also, last night before going to bed and doing the dishes, the water seemed to be very very hot...was coming out of the tap around 160 or so....so I turned the mixing valve on the boiler. This mornings its about 140.
Again, sorry this is not a wood fired furnace....just tough on a Sun morning at 5:30am and wanted to get some help before the furnace blows up as I am afraid to turn it back on if its not going to shut off.

Edit: Just noticed a few drops of oil on the floor next to the boiler. Looks to be an open copper pipe on the side of the boiler that runs vertically then makes a 90 to the top of the boiler at what looks to be a pressure valve of some sort.

 

[peakbagger]

The boiler aquastat is most likely "toast". Most have a bulb that is inserted into the waterjacket of the boiler. As the water heats up its expands a working fluid that opens or closes a relay. Its fairly rare but the bulb or the interconnecting tubing could leak making the aquastat not recognize that the boiler is up to temperature. On older boilers these are fairly standard devices and Home Depot and Lowes may carry them (depends on the store).

Do note that the bulb is not visible as its hidden in the short steel pipe (called a thermowell)that connects the gray box to the boiler.

The aquastat also has internal relays that could have failed.

If you have more sophisitcated controls, the aquastat may have been replaced with a just a single relay and sensing bulb that works as a high limit safety with the controls doing the rest of the aquastat functions.

If you dont feel comfortable working with electricity call a service guy, they carry aquastats in the truck. If possible wait until Monday as the weekend service rate is usually steep. Be aware that the safety relief valve should have opened up to release the pressure and temperature so you should see signs of water at its discharge. If it didnt open up , you need to replace it as this is potentially a dangerous situation.

The piping you described in the edit are the safety relief and its discharge pipe. It should be water coming out of it not oil. When it does open up, ti can release a lot of very hot water and steam so be careful. Based on your description, its time to call a service man to go through the unit as its sounds like its been neglected.

 

[daveswoodhauler]

Thanks for the info Peak. The unit is about 12 years old, and just serviced in October of 2010 for its annual cleaning.
The oil that is coming out of the discharge pipe appears to be very thick/sludgelike...only on or 2 drops on the floor, but inside the pipe is looks to be kinda thick....its not really dripping out..just a few drops of the thick stuff on the floor.
I am guessing that I have 2 issues going on then, one with perhaps the bad aquastat not shutting off the boiler, and second the relief valve being shot.
I am glad that I got up and went downstairs and shut it off.....don't want to know what would have happened if I didn't with the relief valve being not functioning.
Was going to wait until Monday, but I think now I am going to call a tech today.
Thought I was done burning for this year, but glad I have the insert.

 

[woodsmaster]

A lot of relief valves pop off at 32 so yours may have been on the verge of opening if you see a few drops.

 

[daveswoodhauler]

A lot of relief valves pop off at 32 so yours may have been on the verge of opening if you see a few drops.

This is now starting to make sense...A few months ago I noticed a few drops of the oil beneath the discharge pipe..maybe less than a teaspoon full or so, a little less than the size of a dime. So, I am now thinking that the pressure has been getting pretty close over time, and that is what is causing the drops of oil/sludge to come out. I'm feeling a little freaked out if the valve didn't open and what might have happened. The tech would be able to test the valve to make sure it works, correct?

 

[afblue]

It sounds like you are looking at an aquastat and a system flush to see what s in the water in your system. Its most likely sludge in the system. If the boiler is building to 30 PSI for a while you probably have cavitated the circulator pump a few times and the 250+ water vapor cavitates the circulator pump and eats the circulator up.
If the system is heating up and pressurizng to 30psi but not going above 30psi, that tells me your relief valve is working fine.
Drain and flush the system, if you get alot of sludge, take of the circulator and inspect, I dont think the circulator is the problem, but it may be a casualty to the original problem, change the aquastat

 

[daveswoodhauler]

Thanks guys. It was the aquastat....so it seems to be working fine now....goes up to about 200 and then shuts off.
Nothing like a service call on a Sunday to take a few $$$ out of the checking account.....ouch...hopefully one of my kids will go to the tech school and be a plumber/electrician etc...
Thanks for all your help guys!