Expected PSI for Burnham Series 2 205NI-G2?

lbeachmike

My 2013 Burnham Series 2 boiler (205NI-G2) is running at 24PSI. Is that normal/typical? My plumber said it should normally be in the 8-12PSI range.

neilc

25 is high, and getting close to the 30# safety blow off valve,

post pictures of the boiler, at distance, showing the piping, circulator, and the tank,
the tank likely needs servicing, there are 2 types, let's see which type you have and what you have for servicing it,

lbeachmike

Here you go - let me know if you need a close up of anything. Thanks.

lbeachmike

I double-checked and I was actually running at 24 PSI. I know it's an incremental difference, but wanted to be accurate. I don't know if there is much variation when the system is running.

mattmia2

dies it drop to say maybe 12psig or lower when the system is cold? Did you say you found water under the relief valve in your other post?

lbeachmike

I'm not sure what it drops to when the system is cold - I will have to check that. Yes, there was a small amount of water that appeared to be discharged from the relief valve. It has not discharged again since my plumber was here. He said he will return to address that issue, but I want to understand the issue better so I know what to expect as the proper solution. I will have to check the hot/cold PSI readings tomorrow, though I don't think it drops as low as 12psi when cold.

lbeachmike

Is high PSI usually due to a bad expansion tank, or are there other common causes?

bburd

How many stories is the house? This affects the required cold fill pressure.

Jamie Hall

High and variable (hot to cold) psi is almost always a failed expansion tank. Just high may not be; it could also be a leaky autofill valve or something of the sort. Best thing to do is to take the pressure off the expansion tank if you can, and check the precharge pressure (the schrader valve opposite the water connection). If water comes out of that, you've got a problem. It should be set to the system cold pressure -- but you can only do that with no water pressure on the water side.

lbeachmike

House is two stories. Boiler has three zones - 1F, 2F, hot water tank. Plumber suspected expansion tank but tapped on it and said it didn't sound like there was water in it. He took the pressure off the expansion tank and brought PSI down to around 11-12 pounds with the valve from the domestic water side left closed. After I opened that back up and the system ran for a while, PSI rose to about 15 pounds. After cooling down it was back to around 11-12 pounds. While the supply valve was closed, there was a very slow drip at the secondary check valve. With supply valve open, this goes away.

I'm unclear which is the Schrader valve.

Jamie Hall

If it cycles up and down with temperature in the range which you describe, the tank is probably OK. The tap test, though attractive, is quite useless -- but proper variation which you describe is good.

The Schrader valve is on the end of the tank, opposite the water connection, and is usually covered with a plastic cap. It is exactly the same valve as on your car's tires.

I'm not sure to what you are referring when you mention a secondary check valve and a drip when the supply valve is closed. No valve should drip. Where is the drip? At one of the connections with the piping? Is there an open vent on the valve which drips? Perhaps a closeup picture would help.

lbeachmike

Hopefully these are helpful -

Jamie Hall

OK That's either a double check or a reduced pressure zone backflow preventer -- and the drip means that it has failed and either needs service or, more likely, to be replaced.

It's a health and safety thing -- it keeps whatever is in your heating system from getting into your drinking water if the pressure on the latter should get low for some reason.

lbeachmike

>> and the drip means that it has failed and either needs service or, more likely, to be replaced.

Well, it doesn't drip when the water supply valve is open, which is the position it should be in ongoing.

Jamie Hall

That's because when the water supply valve is open normally the pressure in your domestic water supply is greater than the pressure in your heating system.

The drip is from a vent between the two check valves. What it is telling you when the water supply valve is closed the pressure in the heating system is greater than the pressure in the pipe between that valve and the water supply valve. In that situation, the check valves should be closed tight, preventing any possibility of backflow. One of those valves isn't closing tight, and the resulting leakage is the drip.

Now when the domestic water pressure is greater than the heating system pressure and the pressure the valve is seeing, there's no problem -- backflow wouldn't occur anyway, due to the pressure difference. But of your domestic pressure dropped -- perhaps a plumber turns off the main shutoff, or something happens in the street to drop the pressure -- then you will get backflow.

Me, even if it's just water that's been in your system for a few months, I'd rather not drink it. If the heating water is treated, it's probably flat out toxic and it would be best not to drink it. I'd fix the valve...

But it's your call...

lbeachmike

Of course I do not want backflow in my drinking water. So the valve simply needs to be replaced? Do you have an example part number / recommended part? Does the system need to be drained/repressurized?

mattmia2

You can probably find a part number on it. looks like it has unions. Should be able to just shut off the water supply, undo the unions, and replace it.

lbeachmike

I am hoping it is okay to reply to this one-year old thread. What is considered hot and cold for the purposes of getting the respective PSI measurements?