Oil Direct Vent Boiler Replacement

Joe107

I found a puddle of rusty water under my Crown direct vent 3-pass boiler. It's not coming from any of the piping so I'm thinking its the heat exchanger and that I'll be having a new boiler installed but I haven't gotten that verified yet. The boiler was installed in 2008 when we built our house, I guess the days of them lasting 40-50 years are gone. We had some problems with soot the first few years and the boiler shutting down mid-winter despite it being serviced annually. Twice I had to scrub soot off of the siding around the vent.

The unit is 103,000 net BTU/hr. If I remember correctly, the heat loss calculation when we built was 73,000 BTU and we were installing an indirect water heater. We also wanted capacity to add heat for the basement in the future. Crown was recommended to me at the time and I chose this unit because the smaller one was around 75,000 BTU/hr. The boiler is connected to a 12-zone Ultra-Fin radiant system and a 56-gallon indirect water heater. It's set to a maximum temperature of 165 degrees. My questions are: What brand do you recommend I replace this with? Are the direct vent units especially finicky or were we just unlucky? Should I switch to propane due to the sooting issues (natural gas is not an option)

Thanks for your time and thoughts.

STEVEusaPA

I wouldn’t switch to propane, but that’s just my opinion.
The boiler should’ve lasted longer.
Did you confirm exactly where the leak is coming from on the boiler?
Did the boiler ever dry fire?
If your heat loss was 73k, you should install something that size, disregard upsizing for the indirect.

Joe107

I forgot to mention last fall the guy I've been using for service for the last few years recommended replacing the primary control with one that would allow for a post purge to help with the soot so we did that. Doesn't look like we'll get a chance to see if that really helped.

Mad Dog_2

Hold on a minute.  You have all radiant load connected and no boiler protection piping? Make sure its not just sweating.  All the low temp water returning to the boiler will cause SFGC (sustained flue gas condensation) if its not piped and controlled properly.  Ill look again, but I didn't see any protect measures as far as Primary/Secondary or bypasses.  Mad Dog 🐕 

Mad Dog_2

Crown is a fine boiler and Carlin is a  workhorse of the oil burner family.  If it went on long enough, it could rot a hole in the boiler.  I would pull the jacket off, isolate the boiler itself and pressure test it and really get a close look before condemning it.  This boiler never had a chance the way it is piped.  The soot problem was an incorrect flue to air ratio and maybe THAT was never even looked at or set up...let alone got a smoke test and Combustion Analyzer on it.  Do your Due Diligence before replacing this.  Mad Dog 🐕 

Mad Dog_2

God I hate those Robot Arms (intake and exhaust) I know they usually come with the boiler or as an accessory kit, but they look so out of place and strange.  You can have that piped in Hard pipe, you know?  Its a pretty neat job, the guy just didn't know the right way or maybe he didn't read the install manual?  I'm sure in 2008, it most likely was addressed in their manual.  The manufacturers always knew low return temps would wreak havoc on a Cast Iron Boiler. In the Early days,  I piped a Burnham Direct Vent gas boiler exclusively on radiant,  but I believe I put in a bypass and a Thermostatic mixing valve.. whatever the manual said.  I remember the piping diagrams for large volume gravity systems were always in the manuals. Not the best boiler protection, but a decent attempt at the time.  mad Dog 🐕 

WMno57

Robot Arms

HVACNUT

No mixing valve for the radiant?
No buffer tank? What temperature water is being delivered?
Look into the Buderus G115-3 which in conjunction with the Riello BF3 can be direct vent and will deliver 84K BTU input, and the EK-1 Frontier which can be fired at 138K to approximately 68.5K BTU input.
Whatever you do, move the indirect circulator to a location feasible for a normal human being. That's sloppy, as is the combustion air and flue piping as @Mad Dog_2 mentioned.
How long has the pressure switch been disconnected?

Joe107

My oil company sent someone out today to look at it and he confirmed that the heat exchanger is leaking. But they no longer do repairs so he gave me someone to call. I dug out my paperwork and found that the heat exchanger is under warranty (parts only) so we'll try that route first and see what happens.

To answer the questions, STEVEusaPA, no, it was never dry fired. There is a low water cutoff on it. Thanks for the info on disregarding the indirect for the BTUs. That makes a lot of sense since it does have priority.

Mad Dog, the robot arms and vent all came with the boiler. I was there when it was installed. Nobody liked them but that's what came with it and that's what was in the install manual. The diagram in the manual shows it neatly installed but the boiler is several feet from the wall with a straight shot to the vent. That's not real life. We had to put is as close to the wall (a side wall) as possible and placement along the wall all had to work with what you see in those pictures plus the oil tank, the vent, an electrical disconnect (requires 3' width minimum clearance), a sump pit, the basement window, the first floor windows and 2 central air units so we did the best we could. The architect actually had the boiler located on the back wall of my basement which would have put the vent on or around the corner from my patio so at least we avoided that! Early on one oil dealer wanted to replace the intake and exhaust piping and put in a power vent. I called Crown and they advised against it so I left it alone. Smoke tests have been done annually except for a couple years. When I realized he should have been doing them I found someone else for service.

I've never checked the temperature of the return pipe but I know that it is too hot to hold. Never had any sweating issues. This is the first time there's been water on the ground. The manual does talk about a 120 degree minimum for return temp. I will educate myself on the boiler protection piping and discuss it with the next person who is coming out for the leak and I'll look into putting a thermometer on it.

HVACNUT, the Ultra-Fin layout was for a high temp system. The high limit was left at 180. It was reduced to 165 a couple years ago to help it run longer and reduce cycling with all of the zones. The pressure switch has been disconnected for about 6-7 years. The original switch had failed and the replacement did not work so it was bypassed. If you have any suggestions on relocating the indirect circulator, please let me know because I personally already replaced the original and it wasn't fun. It would have been nice if we could have located the indirect a little farther away for more working space but there is a sump pit on the other side of the indirect. Thanks for the brand suggestions, I will look into those if we have to go that route.

Thanks again for all the comments,
Joe

random12345

@Joe107 Where are you located? Have you had your water quality tested or at least looked at the municipal report? 15 years is not long...

Joe107

@random12345 Thanks for mentioning that. We have public water and according to their map we have soft water but I will look into that some more.

random12345

Your boiler's manual will list minimum water quality requirements for chloride, hardness, and pH. If you have soft water, it's probably a non-issue, but I'd check the municipal report anyway.

EdTheHeaterMan

I could not help but to look at the I/O manual. On page 15 Paragraph 3) it clearly states:

3) Low Temperature Systems – Some systems, such as radiant tubing systems, require the system water temperature to be limited to a value below the temperature of the water leaving the ODV. These systems also typically have return temperatures well below the 120F minimum. Figure 20 illustrates the use of a heat exchanger to connect an ODV boiler to this type of system. The heat exchanger will permit the transfer of heat from the boiler water to the low temperature system while holding the system supply and boiler return temperatures within their limits.For this system to work properly the heat exchanger must be properly sized and the correct flow rates are required on either side of the heat exchanger. Consult the heat exchanger manufacturer for sizing information. The water in the boiler is completely isolated from the water in the system. This means that separate fill and expansion tanks are required for the heating system loop. There are several other ways to connect low temperature systems to the non-condensing boilers like the ODV such as four way mixing valve and variable speed injection pumping systems.

This illustration is in the manual


This could be an alternate that may cost less.


This is the diagram your installer selected incorrectly because your system si not "STANDARD".
This will allow lower that "STANDARD:" water temperature to return to the boiler. this lower temperature allows condensation of the flue gas inside the heat exchanger (Cast Iron sections) resulting in premature failure.

Your Warranty on the Crown Boiler Sections may be Pro-Rated to something less than the full value of the cast iron sections. Also there may not be any of those Freeport Series 1 sections available any more. That boiler was replaced by the Freeport series 2 several years ago. You will need to check with Velocity Boiler Works for availability and warranty status. The newer Freeport at the reduced price is still a great option for you, provided you have the near boiler piping installed correctly.

Mr. Ed

Joe107

@EdTheHeaterMan Thanks for your reply. I still have the installation manual and have been reading it now, unfortunately I did not read it 15 years ago. My installer didn't say anything to me about potential low return temperatures and piped it as a standard system. I will be talking to installers about that as we shop for a new boiler. We've called Crown/Velocity and they no longer make an oil direct vent boiler so they say there's nothing they can do for me.

If you don't mind, what are your thoughts on oil direct vent boilers (my house does not have a chimney)? So far I know of two that are available. One is a Solaia, made somewhat locally to me by Boyertown Furnace, and a Weil-McLane. These are from two different plumbing supplys. Both are in the $4500 range, with vent kit and burner, plus labor. Neither boiler is stocked and can take up to several weeks to come in I'm told. I believe New Yorker makes a direct vent but I don't know about availability on that one yet. My concern is that if these are being phased out I could be in a real jam when the next one needs to be replaced. If my current boiler had failed during winter we would have had to winterize the house and move out while we waited to get a replacement. Natural gas is not available to me. I'm considering switching to propane but it will be expensive. I was given a ballpark of $10,000 to bury a 1,000 gallon tank that I would own. And at today's fuel prices there would be no annual cost savings even at 95% efficiency but it looks like I would save some money up front on the cost of the boiler.

Thanks for your time,
Joe

bburd

There are alternatives to a direct vent oil boiler. A conventional oil boiler can usually be vented through the wall using a power venter. These do have drawbacks (oil fumes at ground level; soot stains on siding; mechanical failure) so some prefer to install a pre-fabricated all fuel metal chimney, either inside or outside the house.

EdTheHeaterMan

bburd said:

There are alternatives to a direct vent oil boiler. A conventional oil boiler can usually be vented through the wall using a power venter. These do have drawbacks (oil fumes at ground level; soot stains on siding; mechanical failure) so some prefer to install a prefabricated all fuel metal chimney, either inside or outside the house.

These drawbacks are pretty much identical to the Direct Vent boiler. I like it when the manufacturer has a dedicated DV boiler like the options you mentioned. The DV kit and instructions are pretty much Building Code Official proof. All you need to do is follow the manufacturer's and they have to approve it. If you add a power vent to a standard boiler, there may be some interpretation of the code wiggle room that the Code Official can misunderstand and hold up the whole approval process.

Most Code Officials do not understand oil heat and don't want the liability associated with approving something they don't understand. So they will fail the job so that they can be educated by the contractor. Most contractors don’t want to piss this guy off, so there will be a standoff for several weeks or months until the boiler company and the power vent company provide a document that the inspector can point to that relieves the building code enforcement department of any liability. that document will be placed in the file for future reference. And the inspector will not remember anything about it the next time he comes across the same issue. (Ask Me How I Know This.)

random12345

What about Energy Kinetics Resolute? Specifically designed for DV and multi-fuel in case gas service ever becomes available, plus more efficient hot water.

Roger

Thank you for recommending the Resolute, @random12345 .
@Joe107 , Energy Kinetics would recommend a buffer tank for a radiant system with that many zones (small loads calling for long periods of time means the boiler would likely cycle much more often and be left in standby mode and hot wasting energy if no buffer tank). The Resolute uses "dilution air" direct venting and has a very wide window of operation from low excess air to high excess air; we would expect very clean operation when properly setup and maintained (which should not be difficult). If you'd like to find out more, please visit Energy Kinetics website or call us at (908) 735-2066 (we answer the phone in person).
Best,
Roger

Joe107

@bburd @EdTheHeaterMan Thank you both for your comments. I had someone years ago who wanted to replace the direct vent with a power vent but after some research I decided against it. I did not want to add another layer of complexity and another thing that could shut the whole system down if it broke.

@random12345 @Roger Thank you both for your comments. I did reach to Energy Kinetics through the webpage last night for installers in my area. I don't think I got a reply yet. If not I'll call in the next day or two.

Roger, would the buffer tank be in addition to the indirect?

Thanks again,
Joe

Roger

Thank you, @Joe107 .  I’m sure you’ll hear back from us on the website contact soon. Regarding the buffer tank, yes, the proper way to address your radiant heating is with a dedicated buffer tank.

Best,

Roger