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Is there any way to make a thermostat more ‘sensitive’ ?
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ie, When it is set to 70, it sometimes doesn't come on until the temp gets all the way down to 55. Is there some way to make the thing come on sooner ? If I set it at 70, I don't want to spend half an hour to an hour slowly cooling all the way down to 55 before it comes back on again. I'd like it to come back on at 67 or so.
Besides the comfort factor, I have already noticed that in this trailer, if it gets really cold, it takes much more propane getting it back to a comfortable level than it would take to keep it there. I ran out of propane. Woke up to 28 degrees outside the blankets. Went and got propane. Hooked up my biggest tank when I got back. The furnace kicked on, and stayed on for more than 3 hours to get it back up to 75. (Hey, I was freezing, so I went a few degrees higher, so sue me. LOL) This big tank usualy lasts a week to ten days. At the end of the three hours, it was almost half gone.
Now, I inderstand that the difference between 55 and 67 is nothing like the difference between 28 and 75, but it still seems to me that I am actualy using more propane because the place has to heat up again from a lower temp every time it comes on.
This is a thermostat in a 1981 Layton travel trailer. The thermostat name is Suburban. The furnace is apparently a replacement. It is propane, forced air, of course.
*Luka, I'm not familiar with trailer thermostats but on simple residential thermostats there is an adjustment called an "anticipator" which you can set to adjust the system's cycle time. I'm looking at the installation sheet for a standard round Honeywell thermostat. It states:i The heat anticipator pointer will be set at one of a series of numbers representing the current rating of the primary control in your furnance.. the number will be one of the following: .2, .4, .8 etc. the thermostat's adjustable heat anticipator must be correctly set to accurately control the system on length. An incorrect setting (if too high), can result in wide room temperature swings or (if too low) burn out the anticipator. The current draw (anticipator setting) can usually be found printed on the primary control which is usually a gas valve,a relay or burner control box.You can find the anticipator by simply removing the trim ring or cover from the front of the thermostat. It is a small metal pointer over a graduated scale which you can easily slid back and forth.As I said, this is found on residential thermostats which have a control range of 15 to 30 Vac. I'm not sure if the trailer's controls are the same but its worth a look to see if you can adjust the stat in this manner to decrease your wide temperature swing. Just be very carefull to not short out any of the thermostats connections while you are adjusting it. Hope this helps. Rick
*Ok, this one is a 30 Vac unit. I'm guessing it is the same as any domestic propane thermostat.I had already seen the slider, and instinctualy thought maybe that was what it was for. But had no idea how to know what was the best setting. It is set at the lowest setting. I will get down there to the furnace and see if I can make out what the setting is supposed to be. I slid it up some, a few days ago, and it seemed to take even longer than usual, so I set it back down to the bottom then.Maybe I just need to get a new thermostst. LOL I have never heard a thermostat make moise before, but this one snaps when it turns on. The temp that it gets down to varies. And the colder the temp gets before the tstat actualy comes back on, the louder the snap.Thanks for your reply.b : )
*If you find you need a new stat try to find out if you can use this Honeywell round one (its a Honeywell Model CT87A) Its a "heat only" model that I had to repalce when I installed my central air conditioning a few years back. I know it is still good and I'll be glad to send it to you if you like. I even have the instructions with it which show wiring diagrams and mounting instructions. Let me know. Unfortunetly I can't promise it will "snap" like your present stat. This one has a mercury switch so it needs to be mounted level.
*Thanks again for the reply.Ok, here, I'm going to post a pic to show what the heck I'm talking about at the end of this post.Got down there with the furnace. The brand is suburban, (surprise. LOL) There was nothing anywhere that showed current draw or anticipator rating. Unless the current draw is the 10 amps on the faceplate. In that case, the very bottom of the slider would be the place for it.It's a 12v furnace.Ok, so here's the rest of the story. There is a bi-metal coil in this thing. The upward leg of the thing moves back and forth with the temp, just like the old fashioned mechanical chokes on cars. The top of the leg, when off to the left, breaks contact with a tiny screw, and the furnace shuts off. When the coil cools back down, the leg moves to the right, and contacts that screw, making the circuit and firing the furnace.I adjusted that screw farther in, Moving the end of it closer to the leg of the bi-metal coil. Cutting the gap. Then I set it to 75 degrees. Too warm for me, but I wanted it to cycle. Now, it has cycled 5 or 6 times. It doesn't get down to 70 before the furnace comes back on, and it is keeping the temp fairly constant. So it looks like that has solved it. ...............Ok, now it is cycling on and off every few minutes. Didn't do that at first, but it is doing so now, so I will back the screw back out a bit and see what haps..................Staying off for a bit longer again. Went all the way down to 68 from 75. It looks like I may have to leave it this way to keep it from constantly cyling on and off. Thanks for the offer of the tstat. I'll watch this for a few days, and I may end up taking you up on the offer. b : )It's not snapping anymore. I am suspicious that the snap is being caused by the coil not moving smoothly. It sticks in the off position until it gets so cool that the mechanical strength of the bi-metal pull causes it to snap forward, and the snap that I am hearing is the leg of that coil hitting that screw hard. I have looked closely, and can find no place where it seems to be binding, so it may just be age.I replaced many bi-metal coils on cars when working as a mechanic, and am well aware of the fact that they can and do break down over time. I may do well to take you up on your offer right away, rather than wait and fiddle with this.
*Luka, I laughed when I read i "I have looked closely, and can find no place where it seems to be binding, so it may just be age."In my case it is age. Can't see whatever little thing it is that's causing these sort of problems any more. Joe H
*Luka, E-mail me your address and I'll pack the stat up and ship it to you. I doubt the current draw is 10 amps through the stat--sounds too high. On this thermostat I have the anticipator setting goes from a low of .10 to a high of only 1.2 Your mention of the chokes on cars brought back memories of my first car ( a 1968 Mustang 200cu straight six). I remember working on that single barrel carb with the bi-metal coil on the side of the carb inside the plastic housing. I learned a lot working on that car!! Anyway, let me know. I can have the stat in the mail no later than tomorrow if you like. Rick
*That Honeywell T-87 thermostat is a real piece of American history. How many other consumer products are there that have been in continuous use for so long, and are so intuitively simple for the customer to operate?If I recall correctly, they introduced the thing in, like, the 30's (or maybe it was the 40's, anyway it was very long ago).Think about the first time that you ever saw one of those round, gold, thermostats...Once in a while Industrial Design really hits a home run. Modern microwave oven controls are, on the other hand, crap. Who can figure out how to use a new one right away without having to study the thing? No good reason for it, just lazy engineers (this is from an engineer).I had nothing to add to help Luka, just heard someone mention a T-87 and felt like chiming in!Oh, by the way, just in case the trailer heater controls are different than house ones, you can check your situation at http://www.heatinghelp.com, though it sounds like you've found the root cause and the replacement t'stat might be the end of your troubles.
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Is there any way to make a thermostat more 'sensitive' ?