My two-year old Slantfin Boiler won't heat the house above 65 degrees, and it's usually at 60 degrees. It'll come on and off randomly for short periods of time (as short as one second) and over a long period of time, it may bring up the temp to 65. As another example, I had the (new) thermostat, which my oil company replaced saying that was the problem, up to 72 overnight and into the day, and the temp in the house is still 60 degrees. I have also left the thermostat pegged on high for two days with the same result. The company who installed the boiler doesn't, for some reason, believe that this problem exists, because when they came, the house was "warm" i.e. 65 degrees! and the gauges on the boiler were up to the correct pressure. I have obviously severed business relations with them, but I still have the problem. Any ideas what might be causing this?
I assume this is a hot water / radiator heating system (something utterly unfamiliar to me, as all I've ever known is forced air natural gas).
I would assume that the efficiency of your radiators are the problem, and that measuring the temperature difference of the pipes that enter and exit each radiator will tell you just how much heat that each one is dumping into the surrounding air.
Assuming that the temperature of the pipes that enter the radiators is high enough (I have no idea what that temperature should be - probably
150 degrees, certainly higher than 100) then I suggest you have a few small fans blow air across each radiator to increase heat transfer into the surrounding air.
Sounds like you've got a modern, "high efficency", unit. Among other features, these measure the outdoor temperature and compare it to indoors, and adjust the flame size (and plenty of other things).
We had a similar situation with a different brand, and it turned out to be a mis-setting of the outdoor sensor. This was a new installation by the local Licensed, Insured, and Professional HVAC rep, so he had missed it.
When he came by he scratched his head, then called the distributer, who didn't even have to listen to the whole speach, but told him right away what to do...
Once he knew what to do it was just a couple of minutes of tweaking.
Any chance that if people like me reply to your post that you will follow up with more information etc?
Did they just replace the boiler 2 years ago, or is it a whole new heating system including the radiators etc. that were put in?
If they just replaced the boiler, do you know what the BTU rating of the old boiler was? What is the BTU rating of the new boiler?
If they also put in all of the piping etc. do you know if it a 1-pipe series system, a 2-pipe reverse return system, etc? Is the whole house cold or just the parts of the house that are farther from the boiler?
Were you in the house prior to 2 years ago? If so, was it warm then.
How big in the house, what style (1-floor, 2-floor, ranch, cape cod, etc), etc?
Well, when the heat is on, they are quite hot all over. The problem is getting the boiler to go on and run for a long enough period to heat. I just sat here very chilly for about two hours - the boiler went on for a second or two twice. Now it is beginning to kick in, but it still only stays on for maybe 20-30 seconds. Sometimes it does run for 15 minutes, but not usually.
Well, it's a two year new boiler, but not fancy. I think it's pretty middle of the road. There is not to my knowledge any outside sensor. It's a basic unit.
My old boiler was ancient - 50 year old, big. Then it puffed back and wrecked my house. Anyway, I only replaced the boiler and the pipes leading into it. It used to work fine (the new one). Although my ex-boiler guy insisted that the on and off operation is normal, I really think it's important. I would say the btu rating is less for the new boiler, but I don't know and I don't know what the old one was. I've lived here for 13 years and it is a tiny house - 810 sq.ft. one floor. Mostly new windows and insulation. The whole house is cold and I have no idea about the piping. The weird thing is that it got my house up to 70 yesterday, for the first time in a long while. Today, it won't get going.
Maybe you need to clean or replace the flame Sensor and/or logic card. Newer units usually have a trouble light on the control card that gives a blink code. I doubt that anyone installed a unit that was too small for the building. Then again maybe it just doesn't like you! ;-p
Thanks. That helps a lot. Now that it is clear that this new heater used to work fine, but now is having a major problem getting the house to heat up, that eliminates issues such as poor heater design, inadequate BTU's in the "new" heater, etc.
Unfortunately, I don't know enough about heaters to be able to say what the specific problem is or could be, but maybe others here do now that they have more info.
The heater coming on and off is called "short-cycling", I think. A good HVAC person should be able to figure out why your specific unit is doing that. I know that there can be different kinds of controls or settings that can cause that, but I can't say which one is causing the short cycling problem. I know there are flame roll-out sensors etc. that can be a cause of this type of problems.
I have an oil-fired hot air furnace (I know, that's way different than what you have). It was doing the short-cycling routine. In my case, the heater person came out and found a couple of problems. One was dirt and crud in the chimney flue/vent. That set off some kind of sensor so that soon after the heater started running it would shut itself off. The guy also said that my air intake low temperature setting was adjusted incorrectly, so that meant that the intake air was too cold and that would shut off the heater -- or something light that. Overall, it does sound like some sensor or safety setting is doing its job and shutting down the heater soon after it starts up because it detects a problem. Then the heater starts up again and the whole cycle happens over and over again, which prevents the heater from ever really getting to run a full heating cycle as it should.
Good luck. Sorry I couldn't offer anything more specific. If you do get someone to figure it out, post back here what it turned out to be.
It is certainly unlikely that it's too small for my tiny house. Can I see the the control card without doing something to the boiler that would likely kill it or me?
As I've been "adjusting" my 35+ year-old furnaces (both at home, and at a small commercial office building) for the past 5 to 10 years, one thing is clear to me:
Furnaces are horribly over-spec'd when it comes to their btu output compared to the heat-loss the structure is experiencing - even on the coldest, windiest days.
My furnaces are single-stage, non-condensing, constant pilot light, no electronics in the furnace - but I do have fully electronic thermostats controlling them.
The gas valves inside these furnaces have dial controls - one position to start the pilot, the other (when rotated about 90 degrees) to allow full gas flow through to the burners. These are furnaces that date to the 1970's. (By the early 1980's, furnaces with electronic ignition became standard).
Instead of setting the valves to the full "ON" position, I set them to maybe 20 degrees where I get a stable, SLOW flame on the burners. This is like setting your barbeque gas setting to "low". The result - the furnace runs longer, the heat output at the registers is luke warm, and the temperature inside the structure is very stable and constant. Even when the daytime temp's are only hitting maybe 5 to 10 f (as they have been the past few days) and night time temps are 0 to -5 f.
Having the fan always running adds another "layer" of consistency.
The analogy with a boiler system would be to always be circulating the water, and setting the gas valve on the boiler so as to generate the minimal BTU output as possible.
The most efficient state for a furnace to be in is when it is generating just enough heat to match the heat loss of the structure, and thereby maintaining a constant internal temperature. In this state, the furnace will always be generating heat, and that heat will constantly be in motion, constantly being delivered into the internal living space of the structure.
Modern furnaces that are set to come on at full BTU strength when heat is called for is about as far away from this ideal, efficient state as you can get, as the thermostat or other sensor/control systems struggle to cope with the feedback effects and overshoot / undershoot of the desired set-point temperature.
In many areas, including I'll bet, furnaces, it's not possible anymore to buy something that is really simple. Even the cheapest cars have airbags, etc. for example. So I wouldn't be surprised if you do have the sensor he refers to.
Did't they give you an owner's manual for the furnace? I read mine cover to cover. I didn't understand everything the first couple times but over the years most of it became clear. (or course my oil-fueled forced air furnace is 35 years old.) There will certainly be a reference, if only in the wiring schematic, to outside sensors, although conceivably even then they may be optional.
What make and model number is your furnace? Maybe someone here will find the manual online. But you should still read it yourself. Maybe it's hanging from the boiler?
Hmmm....hot water or steam. I think hot water - I have radiators, with water pipes plumbed into them. Someone recently said steam, but I think that was wrong. I think they are filled with water. I think this is true because when I had the house remodeled when I moved in, the shaky contractor disconnected one of the radiators and flooded my living room. I can also hear water glugging through them a bit sometimes when the heat first comes on. Not a steam sound.
"Pegged on high" mean turning the thermostat all the way up and leaving it there.
And BTW I REALLY appreciate everyone's responses. It seems like a sensor problem
- that something is tripping it. But let me be clear - I am an idiot about these things.
I never even got to really understand all of the workings of older model heater units. Newer heaters are even more complicated with computerized technology etc.
The one thing that someone mentioned about the newer models is that they typically have a small red signal light that is either always on or blinks in a pattern. I have a few of those. There is usually a little peep hole that you look into to see the signal light. The light pattern -- such as 3 short blinks in a row or whatever -- is supposed to indicate what the problem may be. And, most of these have instructions right there on the heater that says what each pattern means. Try looking for that.
I live in an area where our natural gas supply company (PSE&G in my area) will come out and look at my heater for free if it is not working properly. They can usually then tell me what is wrong with the heater and tell me how much it would cost for them to fix it. Their repair prices are usually higher than normal, but if I decide that I don't want them to do the repair, there is no charge for the visit. Maybe if you post the name of the natural gas supplier in your area someone here could tell you if they have that free check policy. Or, you could call them and ask them. In my area, the PSE&G repair technicians really are experts at what they do. I have never had them come out and not be able to tell me within about 15 minutes what the problem is and what needs to be done to fix it.
So, it is a free diagnosis. I often then just have them do the repair, but sometimes with my hot water baseboard/radiator heat systems similar to yours they may say that it is a bad circulator pump. And, they will tell me "off the record" that if I know how to change the circulator pump (which I do, and it is easy), or I know someone who does, I could do it for a lot less than they would charge. That's because they also have to charge to drain and refill the heating system (which isn't really necessary) when they change the circulator pump. Then I thank them, they leave and there is no charge, and I fix it myself or have a handyman person that I know change the circulator pump (the circulator pump costs about $75 at Home Depot -- called a Taco circulator pump, I think; and it takes about an hour max to change the circulator pump).
I own or have responsibility to manage about 12 different dwelling units with different types of heaters and HVAC units which is how I learned some of the ways to solve heating problems at various times -- sometimes on my own, and sometimes with the right people coming in to diagnose and/or fix the problem.
My bet is that your issue is an easy fix if the right person looks at it for you.
Let us know what it turns out to be. Feedback like that, here and elsewhere, is how I learn about a lot of these issues.
In case it helps, I decided to try also posting your question on the alt.home.repair newsgroup which tends to have more people who are active there and may be able to post ideas or suggestions. Check there -- alt.home.repair -- if you want to follow-up in that group.
Oops, I just realized that you have an oil-fired heater, not a natural gas heater. Sorry, that means that it wouldn't help to call the gas company since you use oil, not gas. Duh. My mistake.
Last I checked, if it's hot water, there is a pipe at each end, and a small spigot at the top at one end, with a square peg inside of it, that you can and probably should buy a tool for, to bleed the air out of the radiators, so they will work right. If a radiator is warm or hot to the touch towards the bottom and as you rub your hand up, it suddenly is quite a bit less hot, you have air in the radiator, which will lessen how well it works. That's not the problem you posted about however.
IIRC many people bleed their hot water radiators every year when they start using heat.
If it's a steam radiator last I looked it has only one pipe. (When the steam cools and turns to water, it runs down the bottom of the same pipe the steam is in.) and it has a pressure release valve which is a little bigger than a large spool of thread (if you've ever seen a large spool), with a dome on top, often chrome, and maybe sometimes steam will come out, but my bed was right next to one for 10 years, and iirc it went up to 5 years without any steam coming out.
As I'm telling my friend whose about 60 and has lived in an apartment all his life, but plans to buy a house, if you're going to have a house, you have to know this stuff.
Hi, Modern furnace multi-stage with AI based electronic thermostat generally does a good job. If valve opening is arbitrarily adjusted it is messing with original design spec. When system is installed without proper calculation it creates all kind of comfort and efficiency problem. You are talking about old furnace which nowadays can't even be installed legally any more. I am in Canada. In my house temp. over/undershoot is less than half deg. Celcius which no one even notice.
Short cycling means either system is too big or some thing is wrong specially when temp. setting is not met. I am retired from Honeywell after almost half a century, LOL! I lived thru evolution of technology. From mechanical relay logic to ASIC based electronics control and beyond.
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