Hi guys. It's damn cold, 10 or so during the day, much colder at night. Bad time for boiler problems. But i've got 'em.
No idea what's happening, but from all the reading around it could be short cycling, but I don't know enough to say.
Here's the details:
Natural gas fired Teledyne Lars jvt-100c Was told it's the original boiler from house cinstruction in 1986. If true, it's almost 30 years old. It sure looks it. 100k/80k btu
House sq footage - 1880 plus additional 1000 in basement. Basement is not finished, but there is 1 small baseboard down there. Can't turn it off, it's on the same zone as my den. (I do plan on finishing the basement, roughly 750 sq ft o fit, so please take that into account for future plans)
Hot water baseboards in the house, 3 zones. 2nd floor, 1st floor sans den, and den+basement.
The house is pretty tight.
Now, the problem:
I woke up the other day to find that the house was in the mid to high 50's. Thermostats all set to 67. Boiler was NOT on. Chalked it up to a one time mess up. Throughout the day, the house wouldn't even break 61.
I noticed the thermostats (one for each zone) would all say "Heat On" but in fact the boiler was not running. So....I spent 3 hours in the basement, just watching it. (basement is not finished, but it is tight, and comfy with a jacket on)
What I noticed, is that the boiler WILL fire, but only run for 2-3 minutes before kicking back off. All 3 thermostats still constantly say heat on.
The water feed and return pipes for all 3 zones are scorching hot, and all of the baseboards are getting warm. But NOT hot like they used to. Just warm.
I have NEVER had this issue. I called the only local tech willing to come look at it, only to be told that the office didn't tell him it was gas, he's the oil guy, and can do nothing for me.
He did say that natural gas doesn't work in cold weather, that's why they invented oil boilers. Really?
Well, I gues he IS an oil guy....
Anyway, not sure what's happening. It just won't stay fired. Maybe the super low temps here are more than it can handle? Possibly due to age/wear? And it hits internal temps long before the rooms heat up?
Of course, since I am a newb at this, I could just be talking nonsensical.
Short-cycling seems to fit, but the question is why?
And, based on the age of the boiler, maybe just replace it? My local HD has a slant fin sentry 120k btu marked down to 1300, 1 left in stock. I got estimates of 500 bucks for the labor, so 2k or less for a new boiler. But I have no idea if that's good or not, or what OTHER parts I may need to make it work, pushing price to 3k, 4k, 5k, or more.
So, my questions are two-fold. 1st, what could be happening with my current setup? I need some darn heat!
2nd, based on the age and issues, you think I should just replace it? Is the slant fin sentry 120k boiler good? Is it enough for my 1880 sq ft main area + 750 sq ft basement (once finished)? Is the price good, and what, realistically, should I expect to spend?
BTW - my gas bills are outrageous. My rates are first 30ccf .8108 per 31ccf and up .5404 per, and my bill ranges from 275-300 in the milder fall early winter, to 400-500 monthly november, december, january, and february. Seems like I am paying a LOT more than I should be.
Some forums I was reading, a guy had a 150k btu and a 3000 sq ft home, paying 135 monthly, AND his rates are higher than mine. What the hell.
Anyway, enough rambling. Please, educate me here.
EDIT - Wanted to mention that the boiler is NOT handling HW duties. I have a separate nat gas HW heater for that, and it seems to be working perfectly. SO this is for heat only.