Furnace always building pressure

I have never installed the pressure tank in a horizontal plane like yours is. I've done then hanging and upside down only. I've had remote floor mounted units for large systems, but never the way yours is. I'm not saying it is wrong, just looking over the layout. Many of the old style galvie tanks up in the floor joists were horizontal, but they never had a bladder inside them.
I've never seen a well Xtrol tank in a horizontal configuration either. Let's see what others notice, but that one slaps me up side the noggin' immediately. If all else fails, do you have access to any C-4? That could permanently resolve this dilema. Just kidding, you are very near a solution. The damned trouble all started when you called it a furnace!! It's a Hex on a fine BOILER!

I have to hit the shower after getting a stiff neck.

What kind of setup do you have in the return lines? Looks like you're returning to the aquastat side and the other side is a bypass.

Sting, as I read the original post, I got the impression that there was an immediate increase in pressure as the hot water was being used. I agree with you that the pressure would increase as the stoker warmed the water.

The expansion tank looks like at least a #60 Extrol. That's starting to seem like the problem.

Oddsneds4u Where dose this line go to? Is this a feed to one of your zones? If so I haven't seen it done like that before.

Razzler wrote:Oddsneds4u Where dose this line go to? Is this a feed to one of your zones? If so I haven't seen it done like that before.

That is a cold water line to feed the boiler. If you are seeing the one with the valve on it.
Den
Next to that valve is the taco feedvalve I just bought.

Question on this valve. Should this be turned on or off and what is it for?
Den

ODDSNENDS4U wrote:That is a cold water line to feed the boiler

You had the gate valve turned off and the presure still went up?

ODDSNENDS4U wrote:Question on this valve. Should this be turned on or off and what is it for?

That valve should be about half way to three quarters the way open. It's to add hot water to the cold water returning from the zones so the boiler dosen't get a big cold water shock and it helps in maintaining the boilers temperature.

Razzler wrote:

ODDSNENDS4U wrote:That is a cold water line to feed the boiler

You had the gate valve turned off and the presure still went up? ?

Yes that was an overnight experiment. It still over pressured.
Den

whistlenut wrote:I have never installed the pressure tank in a horizontal plane like yours is. I've done then hanging and upside down only. I've had remote floor mounted units for large systems, but never the way yours is. I'm not saying it is wrong, just looking over the layout. Many of the old style galvie tanks up in the floor joists were horizontal, but they never had a bladder inside them.
I've never seen a well Xtrol tank in a horizontal configuration either. Let's see what others notice, but that one slaps me up side the noggin' immediately. If all else fails, do you have access to any C-4? That could permanently resolve this dilema. Just kidding, you are very near a solution. The damned trouble all started when you called it a furnace!! It's a Hex on a fine BOILER!

Electric Furnace Man

OK it seems you need to do some tests to find your problem. I guarantee you will find it in less than 3 days. Here we go: Step 1: Shut off your boiler and let it cool. Step 2: drain off any excess water/pressure until your gauge reads 12 psi at 120 degrees. Step 3: leave the domestic water coil and the boiler feed lines open like normal and keep the boiler TURNED OFF. Step 4: Check the pressure in 24 hours.

Diagnosis: If your pressure rises then you have a problem with excess water getting into your boiler.

Diagnosis #2: If your pressure remains the same your fill valve and HW coil are good, you have an expansion tank issue.

Shortcuts will lead to confusion so I would just live without your EFM for a day or so and find the trouble. It's easy to restart.

the improper naming definitly negates the hex caused by the furnace vs boiler quandry


I guess the electric boiler man would have a BM in the name and no bowels allwed...... just ask Vanna white

e.alleg wrote:OK it seems you need to do some tests to find your problem. I guarantee you will find it in less than 3 days. Here we go: Step 1: Shut off your boiler and let it cool. Step 2: drain off any excess water/pressure until your gauge reads 12 psi at 120 degrees. Step 3: leave the domestic water coil and the boiler feed lines open like normal and keep the boiler TURNED OFF. Step 4: Check the pressure in 24 hours.

Diagnosis: If your pressure rises then you have a problem with excess water getting into your boiler.

Diagnosis #2: If your pressure remains the same your fill valve and HW coil are good, you have an expansion tank issue.

Shortcuts will lead to confusion so I would just live without your EFM for a day or so and find the trouble. It's easy to restart.

that sound like soild flow chart diagonois! gives ya a chance to shop for the new expansion tank. (thats my secret gut feeling also, due to the sidways mounting...)

The Extrol tank can be mounted horizontally, but supposedly it decreases the life span of the tank. Mine has been like that for over 30 years.

The life cycle was the reason we were always taught to hang them, plus it can be mounted anywhere, not just at the boiler, on the air scoop. I've used the same supply house for 35 years, and that advice is from dozens of plumbing and heating folks over the years.
If it turns out to be the expansion tank causing this issue, the amount of aggravation it has caused would certainly make me re-mount the damned thing just for the time lost. Life is an accumulation of educational experiences, this just being another annoying footnote on that road.......

The feedvalve and DHW coil issue search can be worsened if you have a bad shutoff valve in front of them too, so keep that in mind.

I have a similar problem with my cold water feed valve.

I know it must be bad as if I leave the shutoff in front of the feed valve open the pressure will slowly creep up.

So after I get the pressure set I usually just shut the 'shutoff" in front of the auto fill valve for the Year.

Maybe not the best solution though. I need to replace the auto fill ..