radiant heat source to replace Bock water heater?

DoctorDIY

Hello all.

I self-installed a 3 zone closed-loop system of 2 floors of radiant and one floor of hydronic radiators about 12 years ago in my small (500 sf/floor = 1500 sf) NYC home. The whole thing has been powered by a 50 gallon oil-fired Bock water heater with no issues for all these years. (Well, one day when it was unusually cold, like -15 degrees F, it had a tough time keeping the house warm). The basement has pex in the well-insulated concrete slab. The 1st floor is staple up under hard wood floor, and the top floor has 3 radiators and one towel warmer (run off the 1st floor loop).

Insulation upgraded in the attic, but the walls are still balloon-frame without any real insulation on front and back, attached on one side. I calculate my heat loss at about 45,000.

I came home one day to a bad smell that was coming from the oil burner / Bock water heater. It turns out the combustion chamber has become very charred and the insulation had burned. I shut everything off --it looked like a serious fire hazard. I'm now at the point where it certainly appears the water heater needs to be replaced and the venting re-done. Bad soot buildup in the pipe.

I know technologies have now changed and I want to ask you all what sort of replacement I should be looking into?

My fuel options are:
1. Continue to use oil (I get B20 delivered and my tank is squeaky clean from the 10 years of this). This would be easiest.
2. Upgrade electrical panel to the house so as to accommodate an on-demand self-modulating electric water heater like the ecosmart or the seisco which both appear to be approved for use in radiant heat. Panel is 100amps at present, so I don't think it could handle it.
3. Convert to gas (would require running a new gas pipe from the meter); mine is 3/4" and already has the stovetop, dryer, and domestic water heater running off it.

My thoughts are perhaps a high-efficiency condensing oil-fired boiler, maybe to also handle hot water and get rid of my gas water heater? Not sure if those would be able to heat water for the closed-loop system and also for the domestic water? I'm unclear if those two water sources mix? I looked at some fancy expensive ones, like the energy kinetics and peerless and some other more common ones, but I don't know what the best and easiest would be for my system.

I'm intrigued by the electric as well --haven't figured out if it would be more or less expensive for me, but I like the simplicity of it and the tiny space it would take up. And no venting. Could get rid of the oil tank, too. But I know this would require permits, etc. and it's a little cold now and just before the holidays. I sort of need a quicker fix.

Gas is the least exciting to me, both because it would also require a permit and running a new pipe through my recently finished basement ceiling does not sound like fun. I also just didn't like the guy who came to try and sell it to me. I was hoping for a knowledgable oil person and he faked his understanding of oil and pushed the gas option. He also offered to just replace the Bock, but clearly knew nothing about tuning a burner or doing the venting. So why would I have him do it? The argument in favor of gas is that everyone knows how to service it (more or less) and the venting is pretty straightforward.

Thanks in advance for any help. Please if you can offer specific brands/features to be on the lookout for, that would be helpful. I've become distrustful of many of the installers who seem to just sell what they know and don't take the whole picture into account. So, my solution is to figure out what I want first and then find the right person to do the job correctly based on that. I'd be happy to take advice on reliable, fair, smart NYC-based installers.

Thanks!

STEVEusaPA

First of all you should figure out why the chamber was charred and burned. Lack of maintenance? B20 requires special fuel pump and gaskets and has a host of problems.
If your burner was properly tuned, and had adequate combustion air, it should never soot up. I suspect some moisture in the fuel causing poor combustion.
How do you know your tank is 'squeaky clean'? It probably is with B20, just curious.
No one is really too high on condensing oil, and the smallest most efficient oil boiler is probably too big (if you heat loss is correct).
But the smallest triple pass boiler w/indirect could work, or I would consider an Energy Kinetics boiler.
http://energykinetics.com/90-resolute_multi-fuel_boiler/
Their System 2000 has a unit that sits on top of a small indirect storage tank for a smaller footprint.
With proper controlling I think it would work the best and would be in the high 80's for efficiency (they claim 90%), but only recommended up to B5. You could call and find out that you just may need to purchase the proper fuel pump.
I don't think condensing gas is the better option. For the reasons you mention, and you will have to do maintenance, and you're only getting an alleged few more percent efficiency.
Only if your home was super tight would I consider electric.
You can check the contractor listing for someone in NYC. There are a few great ones on here.

DoctorDIY

Thanks. I think the sooting was due to improper venting (no barometric damper) and recent high winds. Now that everything is drained, removed, I'm going to give the flue liner a good brushing. I suppose it could be water in the fuel. I was sort of surprised they were delivering B20. I thought it was B5 before. Perhaps that combination caused the issue. I also fear that I may have messed with the air intake to fix a smoking problem and caused it to burn too hot. I'm really not sure and should have had someone look and properly test when I got suspicious. At any rate, the thing is wrecked now.

Re: clean tank - the oil coming out looks like canola oil and my filters are always in pretty good shape.

Re: energy kinetics; I'm definitely considering this. Do you think the stackable EK1 Frontier would be a good choice? Am I right to say that the actual water from the domestic hot water doesn't mix with the water running through the heating system. It just gives the heat through an exchanger, correct? I have to keep my closed loop system closed--it has cast iron pumps. I like the idea of the simple (cool) venting. I don't want to burn my house down!

Brewbeer

Are the gas water heater and the defunct Bock in the same space? If so, you could use the gas line to the water heater to run a gas boiler, which could also run an indirect tank for hot water.

DoctorDIY

That's so obvious it's genius. Yes. Sitting right next to each other. Huh.

I read your tag line and thought it was referring to me...

To see if this is even possible...how do you figure the needed gas piping? I have a 3/4 pipe running a length of 30 feet from the meter to feed:
1. gas dryer
2. stove (no oven - that's electric)
3. gas water heater

These are all located in roughly the same area.
I looked at one of those gas pipe charts and it seems this line can deliver about 110,000 BTU, so would that be enough?

Would something like this work for my system, you think?
http://www.ecomfort.com/Rinnai-E110CN/p25141.html

DoctorDIY

My head is starting to spin with all of this. I have a new question: what should I absolutely be careful to avoid in terms of a new heat source?

DoctorDIY

So, if anyone cares to know....update is that I spoke to an oil equipment guy who arrived on time to the appointment and listened to my whole saga.

He was able to scare up a replacement Bock water heater and have it installed tomorrow with new venting and new burner so I don't have to freeze anymore.

Although I was excited about the prospect of a different set-up that occupies less space, is less noisy and efficiently provides DHW as a bonus, the week before Christmas in the freezing cold is maybe not the time to do that.

So, a simple swap-out is the plan. I didn't actually get a quote on any alternatives, so I have no idea if this is an economical decision, but maybe with better maintenance and venting it will last 20 years?

Rich_49

What supply water temperatures do you require ?

Paul Pollets

I would always consider a gas-fired condensing boiler over oil, if gas was available. The ability to make DHW without a separate fuel burning appliance, and a burner that adjusts to outdoor conditions makes more sense than being held hostage to oil. You'll probably need a 1" gas main if handling 3 appliances. Some modern condensing appliances are set up to handle multiple temperatures and DHW with a sophisticated control platform that is user friendly (Viessmann). Finding a good heating contractor is the harder part.