24v relay with loud humm and no noise from circulartor

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NY_Rob

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My cast iron boiler lasted 52 years before I replaced it, others have older gas boilers still running.
Think of it like a car, over it's lifetime you replace the brakes, battery, tires, exhaust components, water pump, alternator, belts and hoses, etc...

The parts you have replaced so far only represent a fraction of the cost of a new boiler- which could run $6-8,000 and upward.
Unless you have a specific reason to replace your boiler, it's more economical to keep that youngster running.
 

Dana

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Lexicon issue: "Furnace" normally refers to heating with ducted hot air. What you have is a "boiler" or "hydronic boiler".

The auto-fill, expansion tank, vents, zone circulators, radiators/baseboards, air-scoops etc. are all parts of a hydronic heating system, but not part of the boiler. It's normal for a 27 year old system to have parts that need replacing, but it's not necessary to replace the whole system all at once. The duty cycle of zone circulators vary (a lot!), so some might be good for 50 years, others 15. It makes no sense to replace them until/unless they fail. I recently replace one on my own system that was only 7 years old, but that's something of a fluke. I have others that have run much longer duty cycles that are over 20 years old now.

It's fairly normal to replace a 25+ year old boiler and leave the rest of it in place, since the combustion efficiency of the boiler is usually measurably declining by then, and the internal control components such as gas valves, relays etc. are all nearing end of life. A 25 year service life is typical for a cast iron boiler, but most will go quite a bit longer if you'd rather just keep fixing it. It's possible to keep replacing all the internal components one at a time, but it's usually more cost effective to pick a date to swap the boiler out, hopefully one that is more right-sized for the design heat load of the house.

One of the guys in my office has a 2-family rental property, and the upper floor unit is heated with a gravity feed boiler that was manufactured in 1922. It's had the gas valve replaced at least twice and who knows what else. It's still running, but so what? The nameplate BTUs in/out indicate 80% efficiency, but it's at least 5x oversized for the apartment it's heating, and it's steady state combustion efficiency has most likely dropped in to the mid-60%s or lower after 95 years of service, and with such a ridiculous oversizing factor the duty cycle is so low it's as-used AFUE is probably in the 40s or low 50s, with as much standby & distribution loss heat going into the basement as there is heat going into the apartment 2 floors above. Is it worth keeping?

In MA the state is offering substantial subsidies for swapping out boilers that are at least 30 years old for a new boiler that is 90%+ efficiency, and he's planning on taking the up on that. I'm not sure what the current programs in CT are doing, but it's worth thinking about updating the boiler within a few years rather than living with it forever.

Don't just hand the task over to an HVAC company to make proposals- the industry track record there is abyssmal, and truly grotesque oversizing it the rule rather than the exception, as if they were expecting it to hit -100F during the next Polar Vortex or something. Since you have a heating history on the place, use the CGM's nameplate combustion efficiency (DOE BTU divided by input BTU) to use it as a measuring instrument, and MEASURE what the heat load is at the 99% outside design temperature for your location. A description of how to do that can be found here. If you can share the relevant information I can run those numbers for you on the forum, if you like.

Then, zone by zone measure up the radiation/baseboard on each zone. The ratio of the load to radiation will determine the water temperatures required, and whether a condensing boiler is really appropriate (usually is). The zone with the least amount of radiation will determine how low the temperatures can be before the boiler will begin to short-cycle itself into lower efficiency and shorter lifespan. A description of how do to some of that napkin-math analysis can be found here.

With some of that all worked out in advance you'll be better able to assess contractor proposals, or to even direct them, or pick the boiler that fills the bill and putting it out to bid, etc.

So, replace the circulator, and start logging fuel use against heating degree-days (wintertime gas bills only.) By the end of the winter you'll have a pretty firm upper-bound for what the true heat load is. If the CGM Series 10 is 4x+ oversized for the measured heat load it's as-used AFUE is going to be quite a bit lower than the nameplate efficiency, and replacing it sooner would be appropriate. (Even the 4-plate version of that boiler would be ~2x oversized for my house. ) If by some miracle it's less than 2x oversized for the 99% load the efficiency gains won't be as much, and as long as the boiler itself isn't getting flaky or leaking, you can probably continue to live with it until you've saved up and scoped out the right replacement.
 

Dana

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It looks like Energize Connecticut is offering rebates on condensing boilers, but they're nowhere near as rich as in MA. (It's not nothing, $750 for AFUE 94% & higher, but paltry compared to $3000 for owner-occupied homes swapping out a 30+ year old boiler up here north of the border, $3500 if not owner-occupied.)

You might still be able to make the numbers work if you take them up on the 0.99% loan deal though. It depends a bit on much do you spend on natural gas in a year, and what the net savings would be.

Retiring an oversized boiler isn't always the first and lowest hanging fruit on the home energy efficiency front, and the money might be better invested in some other part of the house. For instance, most homes in New England leak too much air, and most homes as old as yours (>25 years) don't have any foundation insulation whatsoever. Air sealing and bringing an unfinished basement up to current IRC code minimum (=R15 continuous insulation), can save as much or more natural gas than swapping out a 3x oversized cast iron boiler for a right-sized condensing boiler, often for less money, and providing more comfort.
 

plumbud

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half of my basement is actually somewhat finished. i just completed that task, but I chose not to insulate in the basement so we could enjoy the coolness in the summer months, we just put brand new R38 batts up in the attic when we had to remove old vermiculite which was the best thing we could have ever done, I cool my entire 1200 square foot house very nicely with a single 8000 BTU window air conditioner for a few hours when needed in the summer. Completely removed the need for central air which was an enormous savings. In the basement I have a dehumidifier setup in the summer to run for 3 hours a day which keeps the natural moisture down and I just finished coating half the walls with basement sealer to keep the moisture down as well that's currently hidden behind paneling. Our office is down in the basement and a sweatshirt makes it quite comfortable to be down there in the winter, If i were to insulate the basement walls, , would that keep the basement cool in the summer and keep the house overall warmer in the winter? sometime next year we are also planning to add a drop ceiling in the basement which Can probably also keep the heat in the main section of the house as well?
 

Dana

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That coolness in the basement in summer is actually a mold risk to the back-side of the finish walls, since the temperature inside the studwall cavities can drop below the dew point of the ventilation air. That can be controlled with a dehumidifier, but a dehumidifier converts the latent heat in the water vapor into sensible-heat- hot air, raising the temperature of the basement in summer. Even without mechanical dehumidification amount of "free" cooling BTUs is pretty small too, typically less than 2 BTU per hour per square foot of floor.

But the amount of NOT so free heating BTUs of an insulated basement is substantially higher, since the uninsulated above grade portion of a poured concrete foundation is less than R2, more like R1-R1.5 unless it's unusually thick. Adding an empty 2x4 studwall with half-inch wallboard on the raises that to only about R4 "whole-wall", with the thermal bridging of the studs factored in. When it's 60F indoors and 10F outdoors (a typical coastal CT outside design temperature) you have a 50F difference, and every square foot of above grade R4 wall is losing 50F/R4= 12.5 BTU/hr. You probably have on the order of 300-500 square feet of just the above grade portion of the foundation, so it's representing a heat load at design condition of 3750- 6250 BTU/hr which is probably more than 10% of the whole house heat load, even though it's cool down there!

Even with R15 rigid foam insulated walls my ~1600' basement never gets over 70F in summer, and I still need to run a dehumidifier during muggy weather, but it's duty cycle dropped by about half (!), primarily due to better air tightness. In mid winter it never drops below 66F, heated only by the distribution & standby losses of the heating system, though in spring it'll sometimes hit as low as 63-64F, since the ground is still pretty cold, but the heating system's duty cycle (and subsequent losses) drop to near-zero. By half past June it's back in the 66-67F range, and by September it MIGHT hit 70F. At my house insulating the foundation took about 20% off the fuel use per heating degree-day, while raising the average wintertime temperature in the basement by about 3F, (65-66F instead of 62-63F) and raising the coldest day temp in the basement by about 10 degrees. YMMV.

It's hard to make a case for ripping apart a recently built finished interior just to insulate the foundation, but if you have access to the foundation sill and band joists it's DEFINITELY worth air sealing and insulating those. But it's also worth insulating the foundation in the unfinished areas. There are several threads that cover how to do that on the cheap without turning it in to a mold farm on this forum. In southern New England there are several vendors of reclaimed rigid foam that can make it pretty inexpensive, but there are several details that need to be heeded to keep it mold-free, even with foam.

If you insulate the basement ceiling to a code-min R30 and air seal the subfloor to limit convection between the basement and first floor it'll lower the heat load, but it'll also lower the temperature in the basement making it less comfortable (unless actively heated) and put the boiler on the opposite side of the insulation from the conditioned space, where the standby & distribution losses accrue to the basement only, with at best minimal savings. It's almost always better with retrofits to just insulate the basement walls, so that it's all inside of conditioned space.

A reasonably tight 1200' house with some attic insulation and all of the above grade walls with at least R11s in the studwalls, and NO foundation insulation will usually come in around 23-25,000 BTU/hr @ 0F (cooler than the 99% design temp or most of CT). Insulating the foundation usually drops that to 20,000 BTU/hr or less, while improving the comfort levels in the basement. With a walk-out basement or drive-under garage those numbers will shift around a bit, with somewhat higher heat loads, but not dramatically higher. Your true heat load is almost surely under 30,000 BTU/hr (or very likely would be with a few upgrades to the house), which makes all but the very smallest cast iron boilers oversized. Even the tiny down-fired 3 plate W-M CGa-2.5 has a DOE output of 44,000 BTU/hr, which would be fine if the load is actually 30K, but if it's much under 25K the duty cycle would be low enough that it might not hit it's AFUE numbers. (AFUE is tested at a 1.7x oversize factor.)

I'll be curious to see where the fuel use heat load numbers come out, and what the DOE output of your CGM Series 10 is rated. If it's ridiculously oversized but you're still going to keep it, a heat purging economizer such as an Intellicon HW+ can knock a double-digit percentage off the fuel use. They work by inhibiting the burner on an initial call for heat until the boiler temperture drops to it's low limit, and "learns" the system behavior by monitoring burn cycles, and cuts out the burner ahead of the anticipated end of the call for heat. That lowers the standby temperature of the boiler, lowering the standby losses, and lowers the overall average operating temperature, lowering the distribution losses. The latest-greatest versions run about $250, but you can find older versions around for under $150 if you scrounge. A decade ago it was called the Intellicon 3250 HW+, and was also sold as the Beckett Heat Manager. There are newer-fancier products of this ilk from multiple vendors, but any heat-purging economizer will do pretty much the same thing.
 
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