Anyone with OWB actually able to run pump without fire to stop from freezing?

stumblinhorse

So, this winter I wanted to leave my house for a bit. So I want to find out if anyone actually is able to use the method prescribed by running the OWB circ pump to stop the system from freezing. My set up is a CB eclassic 2400 and a heat exchanger tied into my Weil-McLain cga-6 141k btu boiler.

When I run the OWB circ pump when a zone calls for heat my indoor boiler kicks on and stays on until my thermal fuse gives out in a few hours. WM Boiler can’t have that outdoor <35° water mixed in and heat up enough to shut off.

Wanted to know if there is anyone that is able to get this to work for a month?

pecmsg

Keep the heat at 55* and get a low temp alarm. 

That or drain the pipes. 

hot_rod

You certainly do not want the back up boiler heating the OWF when it is not fired

it will act as a cooling tower. The OWF would need to be a separate loop 

stumblinhorse

It seems that how mine is installed normal practice and everything I read says to simply run the pump. But never found anyone that has done that really. I looked into PGI for the OWB but for 50/50 I would need 200 gals at about $3000. I am not sure putting a bunch of valves in and diverting the OWB water and just running the pump will work either. It gets very cold here. I just trying to find an option that someone says has worked for them.

Draining the OWB is the only option that seems will def work. But it would put the OWB out of commission for the winter since I don’t think I could refill it in winter. Just too cold to run a hose that far and refill.

Anything anyone else has done?

hot_rod

One or the other, antifreeze, or constant circulation, risky if power goes out, or drain it.

You should be able to refill it from inside the building? All you need is a valve with a hose connection in either line to the OWF.

If it is an open system, you would not want to put glycol in it. Exposed to O2, glycol inhibitors break down quickly.

stumblinhorse

hot_rod said:

One or the other, antifreeze, or constant circulation, risky if power goes out, or drain it.

You should be able to refill it from inside the building? All you need is a valve with a hose connection in either line to the OWF.

If it is an open system, you would not want to put glycol in it. Exposed to O2, glycol inhibitors break down quickly.

Yes it is an open system. Hmm. Need to add a fill valve inside. Great idea. I also need to figure out how to completely drain it…

hot_rod

Are the pipes into the building lower than the OWF?
So a single valve becomes the drain port and refill. It may be tricky to add one now, unless you have isolation valves at the OWF?
You could also siphon the unit empty, but the piping would still have water.

stumblinhorse

hot_rod said:

Are the pipes into the building lower than the OWF?
So a single valve becomes the drain port and refill. It may be tricky to add one now, unless you have isolation valves at the OWF?
You could also siphon the unit empty, but the piping would still have water.

OWB is lower than the pipes into building by a couple feet. 80-90% would drain. Not sure what to do with that water inside the building tho…. I think draining outside at the OWB would work and maybe not make a frozen pond. Then once drained it is easy to add in the valves inside to fill.

leonz

The best way to do this would be to use a simple 110 volt transfer pump and pump the water away from the forest eater with 2 hoses; one connected to the boiler drain inside the circulator cabinet and then to the transfer pump and the second hose connected to the discharge outlet of the pump and then laid out to a nearby drainage ditch or a lower point away from the boiler.

GroundUp

I have been doing this for 20+ years for several weeks every winter, and I know dozens of others who do the same. If the system is properly piped and the OWB stays running 24/7 like it's supposed to, the OWB will stay warm. It all comes down to how your system is actually piped. Mine runs through a 40 plate heat exchanger inside my shop which is tied into a pressurized electric boiler system heating my radiant floor, so the 60-70 degree return water from the floor feeds back into the HX which reheats the OWB water. Essentially working in reverse. My OWB water will stay 45-50 degrees when it's 30 below outside. I used to do it with a forced air furnace, and many others including my parents do the same. We also have a very reliable electrical supply here so outages aren't a concern, which may vary your effectiveness. I notice maybe $20-25 extra on my electric bill for a week's vacation in the dead of winter. Frankly, an E2400 is already on borrowed time so I wouldn't waste one penny on antifreeze and I most definitely would not recommend draining it because it WILL spring a leak. Once they're wet, they need to stay wet.

Jamie Hall

Quite so, @GroundUp . Problem is, the OP said he or she wanted to "leave my house for a bit" -- and didn't define "for a bit". Keeping the OWB warm with perhaps a low fire, no problem at all. Going to Florida for two weeks with no one keeping things going... not so much.

GroundUp

@Jamie Hall perhaps you missed the part where I stated that I've been doing this for 20+ years for several weeks every winter, and know dozens more who do the same. It takes a minimal amount of BTU to keep an insulated water tank from freezing. Heck, I even know a guy who just puts a halogen work light inside his firebox when he goes to Mexico for the whole month of February every year and his water never drops below 60 degrees. How many BTU does that light produce? I don't know but it's not a lot.

hot_rod

If the OWF is in an enclosed metal shed, it is easier to keep the back warm as @GroundUp mentioned with a small heater, even a 150w flood light. The critical spot is where the Pex goes into the ground.

That self regulating heat tape was a favorite in Missouri to protect the pipes. The type that you can cut to any length and add a plug on it. Something like 3-4 watts per foot is all it runs, insulate over it with approvedpipe insulation, fiberglass not cheap foam😳

stumblinhorse

Jamie Hall said:

Quite so, @GroundUp . Problem is, the OP said he or she wanted to "leave my house for a bit" -- and didn't define "for a bit". Keeping the OWB warm with perhaps a low fire, no problem at all. Going to Florida for two weeks with no one keeping things going... not so much.

I was hoping to leave my place for about 6 weeks. Anything less than that is not worth the effort to move my horses etc. No way for the OWB to stay warm that long. Outdoor temps regularly nightly -40°f(reason for leaving!).

If I was gone for a quick vacation I would have someone throw logs every day for a few bucks.

Never heard of them leaking if drained. Also not sure why the e2400 is on borrowed time, it is only 13 years old this year.

I don’t see any other option than draining. No way to keep it burning with no one here, not realistic to pay someone to plow snow and add wood to the OWB. Plowing is $200 each storm. 6 weeks would average 10 trips at $2k, not including daily attention to the OWB.

We’ll see since I am gonna do this next winter. Practice draining, install fill valves and fill next summer.

hot_rod

Anything other than draining will be power sensitive. Heaters, circulation, etc. Draining sounds like the only 100% option. Keeping them running is just the nature of the beast, but not always owner friendly.

Hard to tell what the life expectancy for that unit is. It depends on the life it has lead, to some point

GroundUp

Do some research on the E2400. You have one of about 200 left in service- the other 9800 of them have been scrap metal for a long time, most within the first 5 years. When you remove the treated water, oxidation sets in. When you refill with fresh, oxygenated water, the oxidation (rust) gets worse. Draining that boiler WILL have consequences, but perhaps you don't care since you're gone for a good chunk of the winter anyway. "No way" to keep your OWB warm that long, is 100% false. You literally provided the solution in your original post.