Am I doing something wrong

[J1m]

Sorry to have been MIA for so long, things have been a bit crazy with work and such. I had a 40 plate heat exchanger installed along with the fixes to the plumbing, I felt it was the best option at the time. Things do seem better, however I am still using some propane. It seems like the new hx works really well, my OWB temps sometimes drop down to 150-149 degrees from the 180 degree set point, I believe this shows a large heat draw from the house. I appreciate all the help, and would like to hear any comments or suggestions on why I am still using some propane. I'm going to be in contact with my boiler guy to ask the same this week.

I'm no expert, but this has happened to me a few times too - so I might be able to steer you in the right direction.

What is your low set point on the boiler? If your water is getting down to 150, all you need to do is raise your low-end set point. I have mine to come on at 170 and off at 180. Mine is also set up like yours where the oil furnace will come on as a redundancy at 140, so all I have to do is keep my water temp above that and I never burn any oil. Perhaps the other thing you can do is lower the temp at your propane furnace so that it doesn't come on when the water temp is that warm.

If this doesn't help or if you can't understand my rambling, RE is expecting your call.

 

[owbguy]

turn the thermostat on the control for the propane burner to the minimum setting. This will fake out the system in the house so to speak. Then set the control on the owb so that it has a 10 degree cycle not 5. This will increase the time between burn cycles and save some wood. Mine is set to come on at 175 and shut off at 185.

this ^^

 

[Chris-PA]

Sorry if I wasn't clear. In my old home I had an oil fired hot water heating system that I got to know quite well. No secondary wood system at all. When the thermostat calls for heat, the circulator comes on and they turn on the burner in anticipation of a big shot of cold water from the pipes and radiators in the house that's on it's way to back to the furnace. When that gets to the furnace the temperature of the reservoir can drop almost instantly. It's quite common then for the circulator to turn back off until the burner can heat the water back up to the minimum setpoint and let the circuator run again. That's with a burner with a lot of output capacity running full tilt.

So the issue is instantaneous output capacity - the temperature of the internal reservoir may sometimes drop very quickly toward room temp and even with the additional input from your OWB HX I doubt it will keep it above the setpoint to turn on the burner. The heat from the OWB would certainly reduce the amount of fuel you'd use, but how do you keep it from running at all without turning it off or changing the setpoints?

 

[mingom]

Okay I think I'm understanding where you're coming from... I just have heard many stories of those with OWB's setup just like mine not using any fuel during the heating season.

I guess my other question, for those of you with OWB's particularly the 4400, how do you keep your temps up? I have my OWB set at 180 degrees with a 5 degree differential for kick on temp. Since the install of the new HX, i see temps that dip down to 150ish pretty consistently, which to me signifies a significant heat draw from the house (before i would hit 170- sometimes) It seems to be burning pretty decently, its been eating up some wood this past week with temps below zero most nights. I'd like to be able to keep the temps up to a more consistent level, and not have the blower run pretty much 24/7.

Any ideas?

 

[owbguy]

mingom, I have not read all of this thread yet, but are you saying that the water temp at your fire box is hanging at 150ish when you have the damper set to cycle on at 180 and off at 185?

 

[mingom]

Yes basically.. except on at 175 off at 180.. it eventually makes it back to 180, but then falls to 150ish after hitting its 175 blower kick on

 

[owbguy]

as long as you have a good bed of coals and wood you should get immediate response when damper/fan trips at 175. Sounds like blockage of air coming in or going out. If you leave the furnace door open several inches how is your air flow through the chimney? It should be cranking and smoking. If you get good air flow that way and the temp maintains good, then close the door and see what happens to airflow and water temp.

Your heat use should not be drawing the water temperature down from 175 to 150 unless your boiler is severely undersized for the application. The most probable other issues are air flow and what you are burning. If you have good coals and good wood, and the boiler isn't undersized, then it sounds like you have a air flow issue in the boiler.

 

[mingom]

I think this maybe the cause of my issue, if I leave the door open it obviously gets cranking, sometimes even boiling over a bit. However it seems like if I shut the door it can drop off quick. The blower is blowing pretty constant, so I'm not sure its the blower, but it could be having and issue exhausting? For example when I got home the temp was at 181 degrees and 1.5 hours later the temp is down tp 170, with little heat draw from the house. The wood coaled up pretty decent, and its good oak, a year to year and a half season with a few pieces of bone dry pine.

 

[Oxford]

That would have been some useful information to know before we spent a week on plumbing. If your burner is undersized because it can't get enough air, you can change all the piping you want and you'll still be cold.

 

[mingom]

Sorry, this has happened since the plumbing fixes, the burner is sized to heat 5500 sq ft and I'm heating maybe 2500-3000 with the majority of it at 50 degrees, I have two of the loops at 67 degrees. I believe I might have another issue, I'm sorry if you feel like you wasted your time, I don't feel like I have wasted mine. There was an obvious issue with my Hx, it was plugged solid.

 

[mingom]

I know that something is just not working correctly, after reading through others posts about how well their OWB works and heats their house, I believe my newest issue is something to do with correct airflow through the boiler. I believe I should be getting a.) more burn time out of my wood, b.) more ashes than bigger coal-y pieces, c.) better temps from the ETC ( ie set at 180 with 175 kick on... maybe dropping to 170, not down to 150-145). I'm sorry if anyone thinks I've blown off their advice, I've been trying to do all I can to get this working correctly, I just don't know everything 100% about the system. I know it will heat as I want it to. Again, I appreciate all the help everyone has given.

 

[Oxford]

Have you looked inside your boiler? If your HX was plugged solid, take a look at the HX surface of your boiler. As little as .030" of lime scale can have a significant insulating effect, resulting in poor heat transfer in the boiler and requiring overfiring to keep the water hot (i.e. leaving the boiler door open.)

 

[Oxford]

Have you looked inside your boiler? If your HX was plugged solid, take a look at the HX surface of your boiler. As little as .030" of lime scale can have a significant insulating effect, resulting in poor heat transfer in the boiler and requiring overfiring to keep the water hot (i.e. leaving the boiler door open.)

 

[mingom]

I haven't, I'm going to try and dig into that a bit tonight... is there any easy way of seeing into the boiler body itself to see the lime scale?

Also, might be a stupid question, but would sweeping the chimney and doing as much internal cleaning help at all? I'm just not seeing the burn times or quality others are either.

 

[hanniedog]

Sweeping the chimney and cleaning the unit will only help not hurt your situation. I am betting on an obstuction messing up the draft.

 

[owbguy]

I finally went back through all the prior posts to understand the details. Not sure I understand it all correctly. Below are a few thoughts based on what I think has been described. :msp_unsure:

First, I am commenting only on the air flow here. Correct me if I'm wrong. Damper opens at 175 boiler water temp, then boiler water temp proceeds to drop to the 150 range and take a long time to increase to the 180 closure set point. If you leave the boiler door open a crack then it heats fine, fire cranks up and boiler water temp doesn't fall into the 150's? You can crack boiler door, get fire cranking, maintain good boiler water temp, then close the boiler door and have the boiler water temp fall significantly despite the damper open/fan running? If these scenarios are correct, then you have an air intake issue. The damper open and fan running should not allow the boiler water temp to drop off like that if you have good coals and good wood in the fire box. When the damper is open and fan is running you should have high output from your chimney. Check it. Open the boiler door a crack and check to see if there is a difference in chimney output. This will isolate airflow to intake only and let you know if that is an issue. If opening the door does not make much difference in chimney output, then you need to determine if the chimney out put is adequate/proper. How much smoke is coming out the door versus exiting via the chimney? Its possible you have something in the chimney. Burn a creosote log and clean it out. Use a chimney cleaning brush and make sure there isn't blockage.

Second, I am commenting only on the home system heat draw. If I understand your diagram and descriptions, your owb-side water flow has been checked and is now fine. The owb-side water is running in a continuous loop and passes its heat to the in-home system loop through heat exchanger. Your in-home loop is not running continuously and while its idle the owb water temps are fine. Its only when the in-home is activated and running that the owb water temps drop significantly. Is this all correct? If so, the in-home system water temp running through the heat exchanger is cooling the owb water temp, so the in-home system is dominating the owb system. If true, it seems you have a design flaw in the system.

 

[frogg]

what is a wye strainer & what does it do. ?

 

[mingom]

I haven't really tried seeing if leaving the door open brings the temp up fast, usually its way down by the time I see it and I'd have to leave the door open for a long time, which cause the boiler to boil out some water and some good sized flames and smoke to pour out the door. I believe the fan/damper is operating fairly well, if I shut the door almost all the way, I can watch the fan stoke the fire really well. Is burning a crosote log okay for the OWB's? I thought I had heard they're not great on the system. I'm going to look into getting a brush system so I can sweep it this weekend, do I have to completely shut down the fire to do this, or can it be swept while operating?


Regarding the water side of the system. I don't have a definitive answer regarding whether or not the OWB temp stablizes when the home isn't drawing a load. Temps have been on the warmer side (40 ish degrees) the past few days but the boiler still falls to 150-155 degree levels, I can't believe my house is calling for the same load as it was when temps were -7 last week. I'm not trying to say that there isn't an issue with the home side, but I just don't know what would have changed that drastically. The guy I had perform the service on my system a few weeks ago said my system is very similar to ones he's installed, and a very common setup. I have a hard time believing that the past two owners were completely fooled by the system and lied outright to me about how it performed.

I finally went back through all the prior posts to understand the details. Not sure I understand it all correctly. Below are a few thoughts based on what I think has been described. :msp_unsure:

First, I am commenting only on the air flow here. Correct me if I'm wrong. Damper opens at 175 boiler water temp, then boiler water temp proceeds to drop to the 150 range and take a long time to increase to the 180 closure set point. If you leave the boiler door open a crack then it heats fine, fire cranks up and boiler water temp doesn't fall into the 150's? You can crack boiler door, get fire cranking, maintain good boiler water temp, then close the boiler door and have the boiler water temp fall significantly despite the damper open/fan running? If these scenarios are correct, then you have an air intake issue. The damper open and fan running should not allow the boiler water temp to drop off like that if you have good coals and good wood in the fire box. When the damper is open and fan is running you should have high output from your chimney. Check it. Open the boiler door a crack and check to see if there is a difference in chimney output. This will isolate airflow to intake only and let you know if that is an issue. If opening the door does not make much difference in chimney output, then you need to determine if the chimney out put is adequate/proper. How much smoke is coming out the door versus exiting via the chimney? Its possible you have something in the chimney. Burn a creosote log and clean it out. Use a chimney cleaning brush and make sure there isn't blockage.

Second, I am commenting only on the home system heat draw. If I understand your diagram and descriptions, your owb-side water flow has been checked and is now fine. The owb-side water is running in a continuous loop and passes its heat to the in-home system loop through heat exchanger. Your in-home loop is not running continuously and while its idle the owb water temps are fine. Its only when the in-home is activated and running that the owb water temps drop significantly. Is this all correct? If so, the in-home system water temp running through the heat exchanger is cooling the owb water temp, so the in-home system is dominating the owb system. If true, it seems you have a design flaw in the system.

 

[owbguy]

It sounds like you are stumped, so why don't you get the guy who originally set up the owb to come back to look at it? If you cannot get the person who set it up, then call in a reputable owb installer and have it analyzed. We can keep guessing forever without seeing the unit run while you can keep spending money on fuel; or you can simply hire a professional to get the job done today and stop spending on fuel. You spent some money on the new heat exchanger, so I assume you can afford to pay a pro to diagnose and fix your issue. Plus the money you spend on the technician will be offset by the fuel you will not be buying.

 

[mingom]

Not trying to sound like an ass, but just because I spent the money I thought necessary to fix an issue free guidance from a own installer means I have the money to hire someone whenever I feel like it? I wish I did, and I'm willing to spend as much as I can afford.

I don't know who originally installed the system, I wish I did. I had a own technician look over the system, his analysis was the hx issue, however it seems there is more to it than that. I am going to call him today to ask for his opinion on the matter, but I figured the members of this site might be willing to offer their input, as I'm sure others have has similar issues, and free advice is always welcomed. I try and heed everyone's advice that I can, I have a fairly decent technical background but this is my first home, first heating system, first owb, and I'm just trying to get it working and understand it so I can maintain and repair it.