Pressuretrol malfunction?

Peter Sagan

I have a brand new steam oil fired boiler.
Pressuretrol is set up to cut-in at 0.5 psi and cut out at 1.5 psi. Nevertheless pressure goes all the way up to 2 psi or so (at least according the pressure gauge), then the burner shuts off. I think (but I am not sure) it does it on low-water cutoff. Some 2 minutes later it starts again, and after 3-5 minutes it shuts off, and so on. I noticed that during this cycles the pressure never falls beyond 0.5 psi though. Looks to me like the pressuretrol never kicks in. Could it be broken? How often does it happen?

Steve Garson

Peter:

Did you ever find out what your problem is? I ask because I have the same problem.

Big Ed

Boiler Cycle

The pressure con trol seem to be with in range. The gauge and the pressuretrol may be out of sync a little. A short cycle from when the burner shuts off to when it turns on again , can be caused by ....


leaks , lack of pipe insulated or dirty oily water.....

bob young

pressurtrol

sounds to me it is working perfecto to as it is set. cut in = cut-out + differential

Big Ed

I Just noticed

Peter , you sure dug this one from the grave This thread was started pre Christmas......

Steve Garson

Oh well. Mine is not short cycling. It runs around 45 minutes a cycle. All radiators get hot, but the steam pressure or pressuretrol never move. I'm trying to figure out the problem. New vents. Water loss on the watch glass is about 3/8 inch a week when very cold.

Big Ed

Too Long

45min is too long for a cycle. Either your burner is under fired or your load is too large for your boiler.Insulation on the supply pipes will lower the load.

michael_15

You might

You might be lucky ("lucky") enough to have one of the pressuretrols where you can see the little mercury tube inside (I've attached a picture which has one, though it is set terribly high).

If so, the mercury tube (on the upper right) will flip over (like a see-saw) when it hits the right pressure. You can compare this to the pressure gauge.

Because this little tube flips left and right, it's important that your pressuretrol be level along the plane it flips on. Staring straight at the gauge, you shouldn't see the hole in the pigtail. If you can, then that means that when it heats up, the pigtail will unravel slightly and mess with the accuracy.

I'm just a homeowner and so don't have and have never seen one of the other types of pressuretrols (I hear they have wheels or something), so I don't know if there's an equivalent thing you can stare at to see if the boiler shuts off due to the pressuretrol or due to something else.

-Michael

Steve Garson

Yes, I have the mercury tube that I can see, but it doesn't see enough pressure to move, which tells me the gauge is reading the right pressure.

michael_15

I've found that I can check my pressuretrol

by waiting until the pressure gauge reads 2psi or what not, and then just turning down the "main" setting on the pressuretrol until the mercury seesaw flips over. If they don't match, either the pressure gauge or the pressuretrol has issues.

-Michael