Greenwood Question - help!

[91220da]

Like Isee said,
Mastering the learning curve is a big part of it........ 3rd season and I am far from a master but I know I have come along way from the first year. Thanks to alot of help from the guys on here.

Thanks everybody!

Happy Thanksgiving to all, and to all a good nights fire.
Rich

 

[ISeeDeadBTUs]

Above all, ya got to be master of your domain

 

[jbeamer]

Okay, so I thought I wouldn't have to talk to you guys in a while...no such luck!

At 1:00 AM (why does this always happen in the middle of the night?), we heard air in the system again. When I checked the pressure gauge on the oil furnace downstairs, it was rapidly decreasing (and the temp was high). I realized (now that I am slightly more educated about all of this) that I must be losing water so I cut the water to the outdoor stove. When I went to the shed, steam was rapidly flowing out of the PVC pipe in the floor where the PEX lines come in and out. It seems that I ruptured a PEX line! I had no choice but to keep the woodstove shut down -- any water circulating simply ended up on the floor in my shed. Plus, I assumed that since there were no water in the pipes, what harm was there if the stove ran hot?

Okay, now is where I need some input.

1. I am assuming this happened because of last weekend when my stove was running very hot and the pressure was running very high (for many hours). My thought is that this put a "stress fracture" in the PEX line and that it ruptured after a few days of normal use. Does this sound plausible?

2. When the former owner/installer was here and we were having all of the problems inside/outside last weekend, he said the pressure in my system needed to be at 20 PSI (when he installed it three years ago, this is the number GW gave him). I did have a blow-off valve on the back of the GW that was 15 PSI, and the owner said it frequently blew off when he was here. So, when it needed to be replaced last weekend, he replaced it with a 30 PSI blow-off valve. Here's my concern -- my friend the oil furnace guy says my oil furnace (a New Yorker) should run at 15 PSI. The GW manual that I have says that the GW should run at 15 PSI (with a 15 PSI blow-off). Can anyone tell me if there would be a reason to run this at 20 PSI, and if it is safe to do so? The owner said that the systems don't seem to run properly at 15 PSI.

As always, thanks for the help. Today, I need to find someone to help replace the PEX. Then I'm getting a plumber in to give everything a once over before I refire.

 

[sparke]

Most systems will start at 12 psi because most residential refill valves come from factory preset @ 12psi. As your system increases in temp the psi will increase by itself. It will go past 15 psi easily. I think your problem is one of 2 things. 1. The circ pump is not dumping the heat. This can be happen for a variety of reasons, air in system, bad pump, pump not primed, dump zone not adequate, etc... So the first thing I would check is to make sure the circ pump is dumping heat like it is supposed to. Easy to figure out. light the fire, when circ pump activates, you should see the boiler temp drop. 2. It is possible your expansion tank is not big enough to handle your system volume. As the system heats up, the water expansion needs to be absorbed. If not the system pressure will build until the pop offs go. Then as the system refills (which it should be doing if your refill valve is set up correctly) it can introduce more air into the system...

My guess is the plumbing and controls on your system need to be tweaked. You need to find someone who understands the wood side of the system. You would be surprised how many "heating techs" are not knowledgeable with the finer points of implementing a wood boiler into the heating system.

Question, explain to us how your system works. What temp turns on the first circ pump. Where does that circ pump send the water. Is it just to your oil boiler and back? Do you have a second dump zone?

 

[2.beans]

you need to replace the regulator and install a fill valve. the circulator thats mounted horizontally needs the system pressure higher to ensure that it doesnt get air bound.

 

[bigburner]

it looks to me like there are two pressure reducing valves, one has the quick fill option and the other has a screen. These should be set at 12 PSI and the blow-off should be 30 psi. when the system gets hot the pressure with rise to 20 + pounds. Check pressure in expansion tank its should be 12 psi also. Make sure your blatter isn't ruptured that would explain it dumping water. I have never heard of a 15 # blow off for any boiler, pumps don't work well below 10 pounds 2.beans is correct in saying get ride of both. add a auto fill valve and a BFP

 

[jbeamer]

From my understanding (once again, rather limited still), I do have a back-flow preventer. In addition, my system already has autofill. Are you suggesting that I get another one?

My blow-off valve on my oil burner is 30 PSI. On my GW, it was 15 but is now 30.

Had to order the PEX tubing. My step-father (electrician by trade) and I are going to tackle this project as soon as the supplies come in. Definitely not a cheap undertaking - I need 200 feet of PEX (total) and it will cost around $260. I'm replacing both in case the other one also has a weak spot from the steam. When we do, I will also be adding better clamps at the ends. Then bringing in a plumber to give everything a once over.

 

[2.beans]

your auto fill valve in your pictures is really a regulator , you may have a back flow but thats not an auto fill.. have a plumber make your pex connections at each end and get rid of the clamps. how big is your pipe between your boiler and house? is it big enough to put pipe insulation on each pex pipe when you pull them in?

 

[jbeamer]

your auto fill valve in your pictures is really a regulator , you may have a back flow but thats not an auto fill.. have a plumber make your pex connections at each end and get rid of the clamps. how big is your pipe between your boiler and house? is it big enough to put pipe insulation on each pex pipe when you pull them in?

Yes, planning to crimp the connections on each end of the PEX. It's a six inch PVC. The PEX lines have the insulation currently, and I plan to put insulation on the new lines before pulling them through.

So, I'm assuming that the regulator in my picture is acting as the auto fill valve? All I know is that the system auto regulates itself (auto fills as necessary).

 

[bigburner]

when you insulate your pipes,use a high quality product like Armorflex. it cost more but is closed cell foam and will hold up for years, will need you to buy it from a wholesale house , step father probably can tell where to get it, unless it can be bought online, not sure.
What you are trying to prevent is water saturation in the foam, cheaper foam like the stuff you get at a box store, HD or Menard's, fine for dry areas like in the basement. The other is thing you are limited in wall thickness, using the high end product there are several wall thickness to pick from.

 

[RobC]

Is there a chance of foreign material stuck in a check valve, or a strainer some place ? I'm thinking specifically of a check valve incorporated in a pump those could get clogged pretty easily.
2nd Big Burners comment on insulation. The "plasticly foam stuff" will start to melt at higher boiler temps. The better is like a black neoprene foam.

 

[ISeeDeadBTUs]

Inquiring minds wanna know . . . what's the status?

 

[jbeamer]

Inquiring minds wanna know . . . what's the status?

Still waiting for the PEX to come in. They had 100 ft in stock, but I need 200. Should be here today or tomorrow.

 

[willworkforwood]

No experience with underground lines, but I'm still wondering about one thing after rereading the full thread. It sounds like the extra-hot boiler water probably baked the pex. It also sounds like you still haven't completely nailed down the real cause of the problem. Now you're about to send lots more $ underground with the new lines. Is there not a fairly good chance that you will get the exact same problem again, and trash the new pex? Could your plumber install an overheat loop, with some kind of valve/aquastat combo in front of the pex to protect against this? Or maybe one of the more knowledgeable folks on the forum has a better idea for protecting the pex lines from overheating. Something like this might be expensive, but I would have trouble sleeping nights worrying about yet another pex replacement, along with a lengthy outage. In any event, I hope this works out ok for you!

 

[sparke]

No experience with underground lines, but I'm still wondering about one thing after rereading the full thread. It sounds like the extra-hot boiler water probably baked the pex. It also sounds like you still haven't completely nailed down the real cause of the problem. Now you're about to send lots more $ underground with the new lines. Is there not a fairly good chance that you will get the exact same problem again, and trash the new pex? Could your plumber install an overheat loop, with some kind of valve/aquastat combo in front of the pex to protect against this? Or maybe one of the more knowledgeable folks on the forum has a better idea for protecting the pex lines from overheating. Something like this might be expensive, but I would have trouble sleeping nights worrying about yet another pex replacement, along with a lengthy outage. In any event, I hope this works out ok for you!

+1

The original problem was not fixed, what are your plans to avoid the same situation? I agree that the overheat loop should be in front of the pex lines. Either a baseboard set up on the ceiling or maybe even a small buffer tank... Either way there are many many threads describing how to install an overheat loop. We don't want to see you waste $$...

 

[bigburner]

I said this before not sure what thread, I intentionally run my boiler hot [240 max at times]. I still have pex feeding my system. I installed a danfoss mixing valve [backwards - not the traditional install] The t-sat installed is 180 degrees and when the boiler water is above the temp it shuts off most of the feed to the pex, i know someone is sitting there reading this going then what happens "the boiler over heats" I still have 32 degrees left before my storage starts to boil and 60 degrees before boiler starts dumping water. People here talk about learning curve, been there done that. Once I had the buffer tank in by by pass so it was just the boiler, burn chamber has enough room for a double load of wood. So I tried it. Converted a 1000 gals of water to steam, must of had an air pocket and once it starts boiling it just goes Chernobyl. PS the boiler is steam rated also.

 

[jbeamer]

No experience with underground lines, but I'm still wondering about one thing after rereading the full thread. It sounds like the extra-hot boiler water probably baked the pex. It also sounds like you still haven't completely nailed down the real cause of the problem. Now you're about to send lots more $ underground with the new lines. Is there not a fairly good chance that you will get the exact same problem again, and trash the new pex? Could your plumber install an overheat loop, with some kind of valve/aquastat combo in front of the pex to protect against this? Or maybe one of the more knowledgeable folks on the forum has a better idea for protecting the pex lines from overheating. Something like this might be expensive, but I would have trouble sleeping nights worrying about yet another pex replacement, along with a lengthy outage. In any event, I hope this works out ok for you!

You're right, I still don't have an answer as to what caused the original problem. I have been told that it is unlikely that the heat of the water did damage to the PEX. That individual thought it more likely that the steam created in the pex line (for an extended period of time) was the real culprit.

I do have a secondary aquastat that kicks in if the temp on the boiler goes above a certain level. It is my understanding that this aquastat overrides my house and makes the water circulate (in order to cool things down). Does anyone know if I'm understanding this correctly? This secondary aquastat had been set around 230, but I'm wondering if it needs to be set lower?

To willworkforwood - is this the overhead loop you are referring to, or is there something else?

 

[willworkforwood]

You're right, I still don't have an answer as to what caused the original problem. I have been told that it is unlikely that the heat of the water did damage to the PEX. That individual thought it more likely that the steam created in the pex line (for an extended period of time) was the real culprit.

I do have a secondary aquastat that kicks in if the temp on the boiler goes above a certain level. It is my understanding that this aquastat overrides my house and makes the water circulate (in order to cool things down). Does anyone know if I'm understanding this correctly? This secondary aquastat had been set around 230, but I'm wondering if it needs to be set lower?

To willworkforwood - is this the overhead loop you are referring to, or is there something else?

The mechanics that you describe for the overheat loop are correct, but would require the heat load to go somewhere else. Do you have a run of baseboard or a tank in your boiler room like Sparke mentioned in his post? If so, maybe what you do have doesn't have enough capacity to pull enough btus to stop the boil-over. Or perhaps 230* is too high, with your lower boiler pressure - maybe the experts will chime in on this. On the reason for the damage to the pex, it probably doesn't matter if it was hot water or steam - the purpose of the overheat loop would be to prevent both of those from happening.

 

[jbeamer]

Today we tackled the PEX. We had to get a come-along to pull the old PEX out. Sure enough, there was a split in the one line. Now the tricky part is getting the new PEX through. We only made it about half-way (35 feet) and we are stuck. Going to try again this weekend.

The plumber was also here today to give everything a once over. He felt that everything looked good, although he did say that we should consider a better overheat loop. As it is, it seems that my loop simply feeds back to the oil furnace (it doesn't really have an outlet).

I'll keep you posted...