My furnace (boiler) burb...

My oil furnace is a Axeman Anderson Model VESTA. Last night, the furnace burb and spit out a lot of water from a copper pipe that was on the side of the furnace. The pipe came out from the top of the furnace with a valve and down by the side of the furnace. I also notice the furnace running kind of hot as well, 220 degree. Is there something I can do to fix this myself or should I call a pro to check this out? Any help would be appreciate.

 

Your pressure relief valve went off. When boilers get hot and get to around 30 psi, it can trip the relief valve.

Now comes the question as to why the high temperature.

Have you monitored this boiler in the recent past? Or is it only now that you came aware of the situation due to water on the floor? I am curious if the boiler has been gradually getting hotter, or if this is a sudden thing.

Why don't you see what the pressure gauge says first and then report back. Also, it be nice if you could let the boiler cool down. Back off the thermostat a few degrees for a while so everything cools down and the pressurre drops to it's lowest point. Then, turn up the heat again and see what the pressure says after it runs for a while, as compared to how it was when you started it.

The reason is to see if your expansion tank is full of water. It's supposed to be basically air. If it gets water logged instead, what happens is that when the water gets heated, the pressure increases way more (and more quickly) than normal. And such an increase could put it up to that 30 psi threshold that trips off the pressure relief valve.

Then get back with us.

 

Thank you for the quick reponse.

I have notice the furnace has been running quite hot since this summer but nothing severe happened. The pressure usually hoover around 8 to 15 psi when temperature is around 190 degree. But when the temperature went over 220 degree, pressure would goes to 20 psi. I guess my question now is why the temperature is so high and what can I do to bring it down to 180 degree? Is it electrical or mechanical??

 

Well. The pressure is in bounds as is not the problem.

What comes to mind is:

Either the wall thermostat is sticking?

Or the part(s) in the boiler that the thermostat wires goes to will not close down when the wall thermostat shuts off. (a more improbable scenario I think)

Or the regulating thermostat that is in/onthe boiler itself is not shutting off when it should.

........................

Run the boiler and then see if the thermostat shuts off and that the fire in the boiler quits when it does. If that does what it should, then it looks like my last scenario is the cause.

 

On your boiler should be a grey box which measures about 4x6". This is the aquastat, the control for the temperature in the boiler. Turn off the power to the boiler, remove the aquastat cover & look at the settings. There should be 3 knobs with pointers. They will be labeled as Hi, Lo, & Diff. Please post back in this same thread with the settings. Generally they are set for 180, 160, & 10-20 respectively.

 

Grady,

The setting is exactly what you mentioned.

 

You need to confirm the accuracy (or lack there of) of the boiler gauge. This can be done by using a digital thermometer attached to the supply pipe of the boiler. When installing this thermometer, be sure to insulate it well. If the gauge & thermometer agree, you can try turning down the settings on the aquastat by about 20º each on the Hi & Lo. Let the boiler go thru a cycle or two & recheck. It is possible the aquastat is reading incorrectly due to deposits on the exterior of the well or it has lost it's calibration.

 

Okay, I think part of my heating system is fixed. It turns out the venting valve was malfunction according to my HVAC guys. They replaced the valve. I can see steam coming out of the valve so air no longer trapped in the pipe. Everything seems to be fine.

However, I still think the aquastat isn't working properly. Since the vent valve replacement, the pressure release valve still open a little bit from time to time. It does not release as much as steam and liquid like it use to but it does trickle out a little. Here is my thought. My current aquastat is a Honeywell L8124 C 1102. Is there a comparable or better replacement? Where can I get one? Also, how difficult is it to replace the aquastat? Is this something I can do myself? I might not know much about HVAC but I can fix car myself so I am fairly mechanical incline.

Thank you for all your help.

 

I prefer the L7124 electronic aquastat from Honeywell. Until you can get it replaced, turn down the settings on your existing aquastat (Hi & Lo) by about 20º each. Let me know if that helps. You should never see steam out of the air vent.

 

Thanks. How much should I expect to pay for a L7124 aquastat? Can I get one from the internet or should I find one from local HVAC supply store?

 

In my area the L7124 retails for around $275. All I can suggest is shopping around.

 

I believe Grady meant the L7224U aquastat. The L7124U is an older analog aquastat. I bought the digital L7224U aquastat at the beginning of this heating season from a seller on ebay for $58.00. The same person has them for sale again, however it is now $79.00. Still alot cheaper than from any wholesaler.

http://cgi.ebay.com/Honeywell-Triple...QQcmdZViewItem

I wish that it had a larger high limit differential though. I have alot of small zones on my system, so I was getting very frequent, but short firings. I was able to solve this problem with the Beckett HeatManager. This has helped to force longer, but less frequent burner cycles.

Michael

 

L7224 is the "upgraded" version of the L7124. BTW, I would be VERY skeptical of contols at that price, especially off of an auction site.

 

Here is what happened.

I managed to bought a L7224U for $170. Replace the control myself, fairly straight forward. The boiler operates back to normal. It fire up when it goes below 160 and shut of went it gets to 180. Just when I thought everything is done. Last night, the pressure relief valve will not stop leaking. It drip constantly. I put a small coffee can under the pipe but I have to empty it every 30 minutes. So much for my sleep.
This morning, I call the HVAC guys again. This time, they replaced the expansion tank and the relief valve. Fire up the boiler again. The relief valve seems to hold up now. I hope that's the end of it.
I also check out the Beckett HeatManager. Is it really worth to install one??? It seems fairly easy to install it myself. Does it really save fuel?? I know I can pick one up for $160 plus an extra sensor wire for domestic water for about 20.
Thank you for all your input.

 

Beckett guarantees a 10% savings in fuel consumption. I seriously doubt this guarantee would apply to a DIY installation. You would have to check with Beckett to be sure.

 

I am having the same problem and I looked in my aquastat and there is only one control in there and it is set at 180. It that the correct setting? Where are the other settings located?

 

180 is a normal and customary setting for a single aquastat, but if this is your friends apartment, I caution again about working on it ... put pressure on the landlord ... he has a legal obligation to provide heat ...

 

The boiler that I am talking about is mine. Why do you think the relief valve is leaking when I turn the thermostat up. I usually leave it at 71 degrees but when I turn it up to 72 or 73 the relief valve drips. Why is that?
Also another question. I am going to install a Taco control valve control box. The two wires that come out of the factory installed transformer are the black and white power wires. They go to 120 VAC INPUT. Can I directly connect them to a circut breaker and can I also connect them to an existing power oulet? Thanks.

 

Probably because the boiler gets hotter, making the pressure higher, and your system pressure is probably already high for some reason ... and the valve does what it's supposed to do, relieve excess pressure. What IS the pressure on the boiler when the system is COLD, and when the system is HOT ... ?

You really should start new threads though... tagging along on an old thread is not the best way to get fresh answers... you do realize that this thread is three years old, right?

 

How do I start a new thread? I don't know how to do that?

 

When yer at the main list of message, see that blue box at the upper left that says "New Thread" ? Push that button.

Please make the title relevant to the question you will be asking ... that will get the most attention ...