Pressure loss questions...Yes Im a NOOOOOB

[Fred61]

Pressure of 12 to 20 seems like a wide range for constant running of your boiler for a day. Should not swing that much unless the boiler temp is swinging over a wide range like 100 to 180. If it is swinging to those extremes, why? Is your auto fill open replacing loss to the ground from your insulated pex or is your autofill turned on? Pex could also have collapsed during the blow off episode limiting or stopping flow. Careful that it is not giving you false info.

 

[mfoster]

Pressure of 12 to 20 seems like a wide range for constant running of your boiler for a day. Should not swing that much unless the boiler temp is swinging over a wide range like 100 to 180. If it is swinging to those extremes, why? Is your auto fill open replacing loss to the ground from your insulated pex or is your autofill turned on? Pex could also have collapsed during the blow off episode limiting or stopping flow. Careful that it is not giving you false info.

 

[mfoster]

While the system outside has nearly no pressure....the system gauge in here reads at 10ish. I'm going to get a pressure reading from expansion tank in the garage. I pushed the valve, water did not come out.

 

[mfoster]

Is this an auto fill valve.

 

[maple1]

OK - that doohickey might indeed be a blow off valve.

But I think I would replace it with a new one along with replacing that vent - and plumb the outlet of it down to the floor like it's supposed to be. Can you imagine that thing blowing off with someone standing next to it? Or while they were looking at it?

I would also likely put in a new tridicator while at it, and put a couple extra pressure guages in wherever they will go also while at it.

Look like you inherited a somewhat shoddy installation.

 

[maple1]

Yes that is an autofill valve. There should also be a backflow preventer plumbed next to it., in series.

Guages can read different pressures at different spots. Elevation differences between guages can cause that (1 ft. = 0.4psi), and also where they are in relation to circulator inlets & outlets.

Dirt can also get in them & throw them off.

All the more reason for lots of guages. They're cheap.

I read your posts to say one guage would change that much with that much difference in temp. Also that one would go to zero. Is that not the case?

 

[mfoster]

Ok, this is a more useful picture of that. Auto fill valve it is. Now I need to see if it is filling that loop. Appears it runs into oil furnace.

 

[maple1]

It is all one system - water going in there would raise pressure on both guages.

That little lever looking thing on top is a fast fill thing. If you flip it up, it will let water in until you flip it down. Or until system pressure reaches domestic pressure. Unless doing that lets dirt get under it, in which case when you flip it back down water will keep coming in. They can be temperamental, sometimes doesn't take much of a dirt spec to make it not work right. Also should have isolation valves on each side of it so you can shut those off to take it apart & clean it, if it should happen to go wonky with dirt. Or to shut off the inflow if flipping the lever back down doesn't work.

 

[mfoster]

Maple1 is this a backflow preventer.

 

[Fred61]

Don't rely on pressure gauges that old. Also purchase a gauge that maxes out at about 60 which will give you a more accurate reading. Less reading between the lines.

 

[Fred61]

Let me answer for maple

Maple1 is this a backflow preventer

Yes

 

[mfoster]

Maple, just lifted that lever....was able to hear running water for probably 10 seconds, so no major amount. Let the lever back down.

You asked about the movement in gauges...the garage gauge, on the boiler will read zero at 140 or so. When at 170 or even 160 it's running 12 to 20 lbs. Now the basement gauge on the oil unit is steady at 10 or so because the temp here can not move more than 10 degrees because the oil kicks on and regulates. My goal is for oil to never kick on.

 

[mfoster]

OK - that doohickey might indeed be a blow off valve.

But I think I would replace it with a new one along with replacing that vent - and plumb the outlet of it down to the floor like it's supposed to be. Can you imagine that thing blowing off with someone standing next to it? Or while they were looking at it?

I would also likely put in a new tridicator while at it, and put a couple extra pressure guages in wherever they will go also while at it.

Look like you inherited a somewhat shoddy installation.

I would agree for sure on the Shoddy Installation. The previous owner of the home was a contractor believe it or not and he was easily the sloppiest worker I have ever seen. I found an electric power outlet on the first floor made from an extension cord he cut and spliced into the basement. Many issues like that upon move in. Issues like that are why our heating system got a quick check and moved on. We just didn't have time to make changes before winter. My goal is to clean it up and repair in spring time.

Some questions from all this, I have learned what some components are and how they work, but I am still trying to see what is up with low pressure and possible causes or concerns.

I think both you maple, and fred commented on the gauge in the garage on the wood boiler possibly being old or inaccurate. How are you basing age, and is there a way I can replace while furnace is in use. Gauge appears yellowed in photos, its actually snow white when cleaned. Dirties up fast from opening door to fill wood. I can attest to the temps reading fairly close, because I can see the temps fall in the oil unit, when outdoor is low, oil kicks on. Also when outdoor is over the 160 kick on downstairs ,both gauges match while holding steady. As for pressure....It may be entirely off because I have no way to check.

Have we in any way ruled out a break in pex? Would I have ANY pressure with a break in lines.

If my expansion tank is not shooting water, is it possible its still in need of replacement? I did pump some air into it and saw NO rise in pressure on Wood boiler pressure gauge. I am going to find a pressure gauge to check the fill valve on that tank today.

With tending often, probably 6 times yesterday, I was able to maintain 160 plus temps. With an 8 hour sleep period, I had temps at 145 this AM. Is this realistic results with a large box my size?

If that's realistic, its hard or impossible for me to maintain 160 or 165...150 is much easier. Is 150 on the oil furnace end enough to actually heat home through heat exchanger to 69 degrees. See, if I can lower kick on for oil to 155, or even 150...it will greatly reduce oil use. I am however wondering if I lower to that, if the water in the box outdoors will also lower...meaning is my oil spending most its efforts to warm that water in wood box.

 

[Fred61]

Do you have a manual ball valve or shut off ahead of the auto fill.
If you do you can shut it off and run it for a while and check for pressure drop.

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[mfoster]

Do you have a manual ball valve or shut off ahead of the auto fill.
If you do you can shut it off and run it for a while and check for pressure drop.

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I do. I can shot off near the beginning of water supply. I cant really check for pressure drop out in the wood boiler can I? That is all over the board...So I would be paying attention at the oil boiler I'm guessing? Does the Heat exchanger or anything else use water that I should shut off to get an accurate test. Should I shut off circulators or anything?

 

[Fred61]

No. Just stop the water that supplies your system. Should be only one source.

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[velvetfoot]

I replaced the tridicator on my oil boiler with one I bought at Home Depot.

Your system should have the same pressure throughout unless there is a valve closed when it shouldn't.

 

[hondaracer2oo4]

I am late to this party and have read through the responses but may have missed some stuff. If it were me I would do this...

If possible isolate wood boiler from oil boiler and run oil boiler to confirm that he oil side of he system is running correctly. I would bleed off the pressure on the oil boiler side down to zero on the oil gauge and then bring the pressure up to 12 if the oil side is cold or 20 if it's already hot. Then I would run the boiler and make sure everything runs right.

Next assuming that everything worked correctly and the pressure gauge stayed the same I would move onto the wood boiler. I would reconnect the two systems so they are one and look at the pressure gauges. They should read the same. If not than the wood boiler gauge is bad. Next I would fire the wood boiler and see what happens. Close off the water make up valves so no water can be added to the system. If the pressure drops than you are losing water somewhere(water loss= pressure loss). The little air vents are notorious for leaking by and dropping your pressure. They don't last very long, I would actually just find all of them in the system and replace them all now. Check your pressure tanks, they should have zero water come out of them when the Schreader valve is depressed, if you get any the tank is junk, replace it. Also check online for expansion tank sizing and confirm you have enough expansion tank gallonage to absorb the amount of water expansion.

 

[Fred61]

All good advice. Did you see where there was a chance he made steam. That's the concern that I have that the pex could have been comprised.

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[hondaracer2oo4]

I did see that and yes the pex doesn't like to be exposed to those types of temps. If possible to isolate the two systems that would show if the pex is leaking in the underground pipe causing the drop in pressure and the pipe is water logged stealing all the btus away before they reach the house.

 

[maple1]

Unless I missed it, I only saw one expansion tank - at the wood boiler. If that is the case, it likely wouldn't be a good idea to isolate the wood boiler & run the oil?

Valving off the fresh feed & watching for pressure drop was also an earlier suggestion - not sure if that was done or not. But it needs to be if there are questions about possible piping leaks. I doubt it is leaking - or you should hear water coming in through that feed valve constantly if you get your ear up to it if there is a leak.

Pretty sure that wood guage is faulty - both guages should be consistent as it is all one system, even if one boiler is hotter than the other. Aside from aforementioned variations due to elevation & pumping effects. They might be a bit different from each other, but that difference should be more or less constant, one should not be varying the few pounds you describe while the other one is steady.

I"m not sure I would run that thing without replacing some things now - the guage, air vent, blow off valve (and pipe that blow off outlet properly). I would also add in a couple more guages here & there. Verify the precharge on the expansion tank before firing it up again. And maybe add another expansion tank - although that one might be Ok going by the oil boiler guage. Making those changes would require isolating the wood boiler - hopefully there are adequate isolation valves for that. But isolating would also require expansion on the oil boiler too if you wanted to keep running it as mentioned above.

Then also the pump control on the wood boiler should be addressed as mentioned early on - it should run itself so as to help avoid another overheat.

 

[mfoster]

Unless I missed it, I only saw one expansion tank - at the wood boiler. If that is the case, it likely wouldn't be a good idea to isolate the wood boiler & run the oil?

Valving off the fresh feed & watching for pressure drop was also an earlier suggestion - not sure if that was done or not. But it needs to be if there are questions about possible piping leaks. I doubt it is leaking - or you should hear water coming in through that feed valve constantly if you get your ear up to it if there is a leak.

Pretty sure that wood guage is faulty - both guages should be consistent as it is all one system, even if one boiler is hotter than the other. Aside from aforementioned variations due to elevation & pumping effects. They might be a bit different from each other, but that difference should be more or less constant, one should not be varying the few pounds you describe while the other one is steady.

I"m not sure I would run that thing without replacing some things now - the guage, air vent, blow off valve (and pipe that blow off outlet properly). I would also add in a couple more guages here & there. Verify the precharge on the expansion tank before firing it up again. And maybe add another expansion tank - although that one might be Ok going by the oil boiler guage. Making those changes would require isolating the wood boiler - hopefully there are adequate isolation valves for that. But isolating would also require expansion on the oil boiler too if you wanted to keep running it as mentioned above.

Then also the pump control on the wood boiler should be addressed as mentioned early on - it should run itself so as to help avoid another overheat.

First thing I can do is check that valve on expansion tank. I'll test that as soon as I return home. Second is replace gauge on wood unit. Can I do this with unit on...if not what needs done. From looking, I'm thinking it has a line right into the rear, so I may need to shut down and empty system?

Next I will try to isolate systems and check for leak down. Plenty of shut off valves.

 

[hondaracer2oo4]

So First DO NOT RUN THE OIL BOILER ISOLATED IF IT HAS NO EXPANSION TANK, I thought that pic of the expansion tank was on the oil boiler side and someone mentioned that there was a second on the wood boiler side. I appear to have been wrong which will cause the oil boiler to blow off at the blow off valve if working correctly or turn into a bomb if it is not working right. Here is how to properly size your expansion tank, I think yours is to small for one thing http://www.pexuniverse.com/how-size-and-select-proper-expansion-tank.

The gauge can not be replaced without dropping the water level to below where the gauge screws in. Drain water until you are below the gauge level.

 

[mfoster]

Ok, just checked the expansion tank...reads 10psi at the fill or check valve on top. Where should I be?

If correct...I'm leaning towards bad wood boiler gauge as you have all mentioned. Less thinking broke pex line. That auto fill in the basement does not make noise, when I opened it was the first time I have really heard it....also if our water was running constantly our well pump would be working over time.

 

[hondaracer2oo4]

10 psi cold or hot? Should match the oil boiler gauge.