New Boiler Options (or fix 50+ year old unit)?

scotttharobot

Hi there! First post. Just bought a new house with my wife in MN, and it has a 53 year old American Standard 105k BTU gas boiler that is giving us a little grief. Our HVAC company (owned by brother in law with a great local reputation) is stating that it might be a good idea to replace and I'm trying to understand if that's really necessary and/or what good options are. Note system is in a ~120 year old ~2700 sq ft house with cast iron radiators on the top two floors and electric baseboards in the basement.

A little detail on what issues we're having...

- Weird smoky smell on more significant burns (i.e. 4-6 degree change) the boiler (and thus the area upstairs) has sort of a smoky smell. It is possible that it's dust/etc burning off for the first significant warmups of the season. I have C02 detectors all over the house and all read 0. This occurred today when it was 39* out and I kicked the boiler on from 66 > 70. We did recently have a flue cap installed (and the HVAC company said they didn't like the type that was installed as it's too restrictive), but didn't note a concern on venting / flow. Wondering if it's worth removing the flue cap and recreating the conditions and see if that's causing issues? Though not an expert, i'd expect if the boiler wasn't venting properly I'd have high CO2 readings through the house.

- HVAC company was recently at the house in September, as the boiler makes an ambient noise when off that sounds like the gas is on emitting from the burner (but it has no smell). When turning the gas off the noise stops. Two different boiler techs have came out and said they can't find an issue. They did replace a thermocouple and cleaned/tuned the boiler (which reduced CO readings from 1000 > 20).

Really trying to avoid a situation where I'm down a heating system in the depth of winter so leaning towards replacing - 53 years is a good run in my opinion. We also have a slightly older water heater, and ideally would love to relocate the system (it's in the middle of a room, and if we move towards a wall, can better leverage the space). I've read a bit on combi boilers but sounds like many of them are cheap junk, and I'd love to have something more bulletproof and reliable. So - any thoughts on the issues we're experiencing, and any recommendations on types of systems to consider? Thanks in advance!

mattmia2

Are the electric baseboards on when you smell the smoky smell? Those definitely get hot enough to burn the dust that has accumulated on them. Burning gas usually doesn't have much of a smell. It could be something that is getting heated but that something could be the vent of the boiler but it could also be framing too close to the vent or the 120 year old chimney too so you have to make sure there are no vent issues.

hot_rod

Replace the beast, if piece of mind and fuel costs are the priorities

WMno57

scotttharobot said:

I'd love to have something more bulletproof and reliable.

Almost no boiler installed today will last 53 years. They are more efficient at the expense of reliability and longevity. A Wallie here has a saying, "Can't see it from here". We cant see your boiler from here, so hard to give you keep or replace advice. Age alone means nothing. There have been 5 year old boilers on HeatingHelp that have failed. My 75 year old boiler is just fine. Not everything old is great, but some old boilers have proved themselves over time. These proven reliable designs are no longer allowed to be sold today by our government.
In Minnesota, you need backup heating plans. New boilers can breakdown and parts can be two weeks out. Your old boiler is probably better suited for generator power, than a new boiler with sensitive electronics.
What are your plans for Air Conditioning? A heat pump in combination with your boiler would give you some heating redundancy.
You are farther ahead than many here, in that you have had professional eyes on your system, and you have family in the industry.
I think you should first get additional advice on the chimney, and figure out the source of that smokey smell.

hot_rod

Nobody I know can predict reliability. A new cast boiler and indirect tank would cover both concerns. More efficient heat, DHW, and more that likely more reliable.

I think you have CO detectors? Hopefully low level models. CO2 is what you exhale

mattmia2

hot_rod said:

Replace the beast, if piece of mind and fuel costs are the priorities

I'll ask Ed's question, when you replace the boiler then still smell it, what do you do next?

scotttharobot

mattmia2 said:

Are the electric baseboards on when you smell the smoky smell? Those definitely get hot enough to burn the dust that has accumulated on them. Burning gas usually doesn't have much of a smell. It could be something that is getting heated but that something could be the vent of the boiler but it could also be framing too close to the vent or the 120 year old chimney too so you have to make sure there are no vent issues.

Update, I climbed on the roof and removed the recently installed flue cap and the smell is gone. The fireplace guys installed one of these on the flue cap which was too restrictive. I have a much more free flowing flue cap on order and will install that and hoping for a better outcome.

hot_rod said:

Replace the beast, if piece of mind and fuel costs are the priorities

I think that'll be the plan. Any recommendations on brands / models to look at? I'm leaning towards a standard efficiency boiler (to minimize complexity & maximize reliability) and our HVAC company recommended Alta Boilers from US Boiler or Well Mclain. We are also thinking of preemptively replacing our water heater which is older as well.

WMno57 said:

scotttharobot said:

I'd love to have something more bulletproof and reliable.

Almost no boiler installed today will last 53 years. They are more efficient at the expense of reliability and longevity. A Wallie here has a saying, "Can't see it from here". We cant see your boiler from here, so hard to give you keep or replace advice. Age alone means nothing. There have been 5 year old boilers on HeatingHelp that have failed. My 75 year old boiler is just fine. Not everything old is great, but some old boilers have proved themselves over time. These proven reliable designs are no longer allowed to be sold today by our government.
In Minnesota, you need backup heating plans. New boilers can breakdown and parts can be two weeks out. Your old boiler is probably better suited for generator power, than a new boiler with sensitive electronics.
What are your plans for Air Conditioning? A heat pump in combination with your boiler would give you some heating redundancy.
You are farther ahead than many here, in that you have had professional eyes on your system, and you have family in the industry.
I think you should first get additional advice on the chimney, and figure out the source of that smokey smell.

Great points and questions. We are also looking at adding central, high velocity mini duct A/C system through the house. I've read up on hybrid heat pump / furnace systems, but I'm not sure if that's applicable in a seperate ducted A/C & radiator setup? I guess the question is, could a heat pump system run cast iron radiators and interface with a boiler?

hot_rod said:

Nobody I know can predict reliability. A new cast boiler and indirect tank would cover both concerns. More efficient heat, DHW, and more that likely more reliable.

I think you have CO detectors? Hopefully low level models. CO2 is what you exhale

Ha, you're right - my mistake!

mattmia2 said:

hot_rod said:

Replace the beast, if piece of mind and fuel costs are the priorities

I'll ask Ed's question, when you replace the boiler then still smell it, what do you do next?

See note about smell dissipating above!

WMno57

scotttharobot said:

We are also looking at adding central, high velocity mini duct A/C system through the house. I've read up on hybrid heat pump / furnace systems, but I'm not sure if that's applicable in a seperate ducted A/C & radiator setup? I guess the question is, could a heat pump system run cast iron radiators and interface with a boiler?

Assuming you are not a candidate for Geothermal, Heat Pumps are air source. They come in two types; Air to Air (AtA), and Air to Water (AtW).
I'll discuss AtA first. ATA is most similar to central air conditioning. AtA can also blow lukewarm air on spring and fall days. AtA could keep your house livable in the dead of winter if your boiler dies.
AtW is much less common. AtW can circulate lukewarm water through your radiators in the spring and fall, and circulate cold water or refrigerant through a coil with an air handler (fan) for summer air conditioning. But if you have ducts and an air handler for AC, what's the point of running lukewarm water through your radiators? Just run lukewarm air through the ductwork. AtW has drawbacks. The two biggest are uncommon (less choice and support), and may require Glycol for freeze protection. Glycol should be avoided if possible.
Running cold water through the existing radiators in summer would cause them to drip condensation from humid air. So can't do that.
In my opinion, you should focus your search on an AtA heat pump, which will give you summer AC and some winter heat backup.
Keep the natural gas, radiators, and boiler. Some day you may need to replace the boiler, or maybe it has 40 years of life left.

hot_rod

If you want a new boiler and have the budget, by all means do it. The industry needs your dollars

US Boiler, Weil Mclain, Crown, Utica/ Dunkirk, Peerless are some of the common US cast iron boilers. Buderus, Basi imports.

EK is another popular choice, worth a look, the "anti cast iron" brand.

tim smith

If you have had boiler serviced, and burners and heat exchanger reported in good condition. Draft checked to verify not spilling of flue gasses out diverter, combustion checked. I would not worry about replacement. Unless the fuel savings is intriguing enough. If I wanted a/c and did not have the budget for both a/c and boiler with above being true, I would do the a/c. Again, it all depends on how well existing boiler has been maintained.