EFM Pressure Is Too High

My efm has worked fine since I moved into this house 7 years ago. Lately the pressure has been going over 30# and will not come down unless I trip the releif valve. Looked over all the post in here and only conclusion I can come up with is maybe my coil is clogged. Looks like there is some rust spots on back of unit around coil plate. I drained all lines to copper heating units, thought I had air in lines. I am at a loss. Can anyone help.

If you have a domestic hot water coil in the boiler, it could be leaking water into the water jacket. The domestic line will be of a higher pressure.

Dallas wrote:If you have a domestic hot water coil in the boiler, it could be leaking water into the water jacket. The domestic line will be of a higher pressure.

On another post someone said, if you release the pressure and turn off all the water into the unit that pressure should not rise. Unless of course there is a pinhole leak in the coil.

If you have the domestic coil, you have two water inputs into your boiler ... the "domestic hot water" and the "boiler feed". If it isn't the domestic coil, it would be in the "boiler feed". Eliminate one or the other. Of course, shutting off the boiler feed would disrupt your life less, while troubleshooting.

You only have to turn off the water supply to the inlet and outlet of the coil. If the pressure remains within range, (boiler temperature will determine pressure), you have found your problem as a pinhole leak in the coil. Is your water acidic?

If the pressure still climbs, turn off the water make-up to the boiler and open up the coil again. The problem will then be in the pressure reducing valve.

Another potential problem is a broken bladder in the expansion tank, or a full ceiling-hung expansion tank. If the boiler is left to cool down, the pressure will drop.

Check these out and get back to us.

Sorry Dallas, we're typing at the same time

stoker-man wrote:Sorry Dallas, we're typing at the same time

I thought you were out on a service call.

what's the water temp? Mine will get up to 26-27 psi at 220 degrees, at 60 degrees it's 15psi. My tank is too small technically speaking, but the pressures stay within acceptable limits and never exceed the PRV 30psi rating so I live with it. put a bucket under the PRV pipe and see if it fills up, if it doesn't then don't worry about it.

stoker-man wrote:You only have to turn off the water supply to the inlet and outlet of the coil. If the pressure remains within range, (boiler temperature will determine pressure), you have found your problem as a pinhole leak in the coil. Is your water acidic?

If the pressure still climbs, turn off the water make-up to the boiler and open up the coil again. The problem will then be in the pressure reducing valve.

Another potential problem is a broken bladder in the expansion tank, or a full ceiling-hung expansion tank. If the boiler is left to cool down, the pressure will drop.

Check these out and get back to us.

OK, dropped the pressure in the unit. Then I closed off the inlet and outlet of the coil. Water pressure went to about 33#. Dropped the pressure again, opened both valves and closed the make-up valve. water pressure stayed the same. The entire time I was maintaining a temp of about 190 degrees. The expansion tank is new because the bladder got a hole in it, I"m thinking maybe water is acidic. Would also like to know what kind of pressure should be in the expansion tank. When I checked it after doing your test it showed 22# . Just another note, maybe this is a combination coil and reducer problem. When my wife turned on the hot water after the tests it was all dirty looking. Thank you for all the help so far.
P.S. It is too darn cold to turn off this baby.

opened both valves and closed the make-up valve. water pressure stayed the same.

What was the pressure? zero or 33?

Drain the boiler just enough to reduce the pressure to zero. Measure the pressure at the tank. The expansion tank should be pre-set to around 12#. If not, let some air out (or add).

Probably the rush of water into the coil when you opened the valves stirred up some sediment inside the coil. Nothing to worry about.

Your test kind of rules out the coil. Where else could unauthorized water be entering the boiler system?

By the way, if you have rust around the coil gasket, it's because it leaked in the past. Tighten up the coil nuts a little each year. In the worst case scenario, a patch plate is available to repair that area. See the pictorials of the boiler.

You say your boiler is "so old". What is the serial number?

the fill valve, or pressure reducing valve might have a strainer in it. Take it out and clean it, mine was full of junk and the thing wouldn't shut off over pressurizing the system.

Automatic fill valves can fail. Sounds like your may have. The solution is to replace the automatic fill valve.

If your house has 40 or more pounds of pressure and the boiler never goes over 33# its the boiler feed pressure valve. It could need adjusting, cleaning or replacement. I would start by backing off the pressure setting and blowing off the actual water pressure in the boiler. If it comes back up to a lower pressure, adjust it back to about 12-13#. If it stays there, your all set. If it climbs, then you have work to do.

It could also be your gauge is bad.

If you put in a new one do yourself a favor and install ball or gate valves on both sides of it. I forgot to put one on the boiler side of mine, so even though it needs changing I really don't feel like draining the boiler. Live and learn.