Newbie- Thermostat question

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Old 11-22-11, 02:57 PM
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Newbie- Thermostat question

Hello all,
I am new to this forum and would just like to say how helpful this site has been to me. With that being said, I have a technical problem that I am hoping you all can help me with. Here is my situation...
I have oil heat at home. I have two zones on my boiler. One zone is for my basement which is baseboard heat. It has its own thermostat to control the the pump that sends water through the baseboard. Zone 2 is for the 1st & 2nd floor. These two floor has radiators. Zone 2 has another thermostat here that turns the boiler on/off.`The problem that I am having is that the basement would get colder faster than the 1st and 2nd floor. This means that the Zone 1 thermostat activates the pump but cold water is sent through the baseboard lines. Only when the zone 2 thermostat activates and turns on the boiler would hot water start going through the lines. I was just curious to know if there is any such device that I can use to turn on the pump with the zone 2 thermostat. This way when the boiler comes on, so will the pump. It will save me a lot of money since the pump would not be running all the time with cold water in the lines. I am also open for other suggestions.

Thanks in advance...
 
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  #2  
Old 11-22-11, 03:18 PM
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Each thermostat should be turning the boiler on. Do you have one pump and two zone valves or two pumps and no zone valves? When you follow the thermostat wires back to the boiler room, where do they connect?
 
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Old 11-22-11, 03:39 PM
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This may be a STEAM boiler with a hot water loop in the basement...

Mosil, can you tell us if the radiators are STEAM ?

Is the pump for the baseboard in the basement the ONLY pump on the system?

If so, then you wouldn't want the Zone 2 t'stat to turn on the pump...

Instead, you might need to add a control which would fire the boiler when Zone 1 calls for heat.

If you are unsure what type of system you have, and own a digital camera, you can set up a FREE account at Image hosting, free photo sharing & video sharing at Photobucket and upload the pics there. Come back here and place a link to your PUBLIC album and we'll look at the pics and advise.
 
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Old 11-22-11, 07:26 PM
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NJ Trooper,
You are correct, the radiators are steam. The pump only controls the water flow through the baseboard in the basement. When the thermostat in the basement kicks on, it sends 110V to engage the pump. This is the only pump on the system. I am trying not to use a second control in the basement to turn the boiler on/off only because it will be very costly. The basement gets cold very quickly and the boiler would constantly be turning on. I was hoping that there was some sort of relay device that can be triggered by Zone 2 thermostat to turn on the boiler as well as the pump simultaneously. You suggested that I don't do that in your post. Would that be a hazard?
 
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Old 11-22-11, 07:32 PM
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No, not a hazard, just that it wouldn't make much sense... but I see the logic in your line of thinking, so let's talk about that a bit.

When zone 2 calls for heat, the boiler fires up to make steam. Naturally the water in the boiler gets hot... and yes, you _could_ trigger the pump to run and heat the basement.

BUT, since you are saying that the basement cools quickly, then it wouldn't be much help, because zone 2 still would not call often enough to keep the basement heated, right?

more...
 
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Old 11-22-11, 07:36 PM
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So, you need a way to get the boiler hot more often in order to keep the basement heated... the zone 2 heat calls won't be enough... that is, if I understand what you are saying.

Instead, you DO need a way to get the boiler fired up IN BETWEEN zone 2 calls in order to maintain the temp in the basement.

This can be accomplished by installing an AQUASTAT on the boiler which would allow you to fire the boiler to heat the water in it, but CUT OFF the boiler BEFORE it gets hot enough to STEAM.

more...
 
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Old 11-22-11, 07:41 PM
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Yes, of course it will take more fuel to keep the basement heated... you need to produce more btu's and the only to do that is by burning fuel...

So, BOTH thermostats will have to fire the boiler.

Zone 2 will stay wired the way it already is... no changes... when it calls for heat, the boiler will be under control of your Pressurtrol and will make steam as it should.

Zone 1 , the basement, will still control the pump on/off, but in addition it will have to fire the boiler to heat the water up to say 180 and then shut off the burners because what you DEFINITELY DO NOT want is for the basement zone to make STEAM... this would overheat the upstairs for certain!

See where I'm going with this?

You need to leave the upstairs alone, and instead allow zone 1, the basement, to call the boiler in addition to running the pump.
 

Last edited by NJT; 11-22-11 at 08:57 PM.
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Old 11-22-11, 08:30 PM
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@NJ Trooper
Thanks for your quick response! The aquastat sounds like the most logical thing to do but I was really hoping that there was a way to trigger the pump with the Zone 2 thermostat. Maybe I should elaborate a bit more to give you a better idea of what I am trying to accomplish.
Zone 1 and 2 thermostat are set in sync...meaning that the both are set to heat up to 70 degrees at 5pm and go back to 68 degrees at 10pm. Once this is accomplished, the basement loses the heat faster than the 1st and 2nd floor and the pump engages again but is now pumping cold water since the boiler is off. I am not really concerned about getting the basement back up to 70 since it is not a priority. The pump running constantly until Zone 2 thermostat kicks in again and this is what I am concerned about. The pump gets very hot and is also using electric. So having the pump turn on when Zone 2 thermostat kicks on and shut off when Zone 2 thermostat turns off would be ideal for me. My main concern here is all about saving electric and not burning the pump rather than keeping the basement at a steady temp. I hope that I have clarified things a bit more....something that I should have done in my first post.
 
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Old 11-22-11, 08:54 PM
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OK, that does make the picture a bit clearer!

In that case, what it sounds like you want then is an 'interlock'... no matter what the basement t'stat says, the pump won't run unless upstairs is calling for heat...

In other words, you don't want that pump to run unless BOTH thermostats are calling for heat...

I think you could do this pretty easily... with something like a Honeywell R8845 or Taco SR501 relay. Each of these relays have multiple sets of contacts. What you would do then is wire the upstairs thermostat to trigger the new relay instead of the boiler.

One set of contacts would wire back to the boiler in place of the upstairs thermostat so that signal passes through the relay... (use the X1 and X2 on the 8845 for this)

The other set of contacts would wire in the HOT 120 wire to the pump. (use one set of the power circuits on the 8845 for this)

Here's the install PDF for the 8845 (the 501 is similar)

http://customer.honeywell.com/techli...it/69-1292.pdf

So, the sequence would be:

Upstairs thermostat calls for heat.

New relay is triggered.

Relay passes heat call to boiler.

At same time, it completes circuit to pump.

Pump will run ONLY if basement thermostat is ALSO calling for heat, but will NOT run unless BOTH thermostats are calling for heat.

Sound like what you want to accomplish?

Here is a source for relay on-line:

Patriot Supply - R8845U1003
 
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Old 11-22-11, 09:11 PM
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NJ Trooper,
That is EXACTLY what I need. I will purchase/install it and let you know how it all goes. Thanks you so much for your time and patience. I am very grateful......


Mosil
 
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Old 11-23-11, 01:38 PM
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Mosil, if you need any help with wiring what goes where, just let us know.
 
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Old 12-08-11, 07:26 PM
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Will do... I placed my order today through Patriot supply. I should be getting the R8845U1003 in a couple of days.

Thanks again!
 
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Old 12-09-11, 03:05 PM
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Here's a diagram ... questions?

 
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Old 12-13-11, 06:45 PM
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Hi Trooper,
I received my 8845U today. I was looking at your diagram and had few questions. Here is what I got so far....

1. Disconnect/Cut the wiring from the upstairs thermostat to the boiler.

2.(R/T) & (W/T) - connects to the two wires from the upstairs thermostat side. Does phase matter here? My wire are Blue and Black and NOT Red and White.

3.(X1) & (X2) - goes to the two wires on the boiler side (Disconnected from the upstairs thermostat in step 1). Again, would phase be an issue here?

4. L1 and L2 - L1 being the HOT and L2 being the Neutral (Pretty straightforward).

5. Terminal "C" - Unused.

Here is the tricky part which I don't understand.

1. Do I need to put a Jumper between "COM" and "L1" as stated below?
2. Can I just jump Terminal "A" to "L1" and also the Neutral from the Basement pump to "L2"?


Currently the way the pump is setup in the basement is that the thermostat makes/breaks the HOT connection to the pump. This means that if I am to follow the below diagram, I would need to run
and extra set of electrical wiring which is why I am hoping that I can just jump it on the 8845U itself. Please advise.


Thanks
Mosil.
 
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Old 12-13-11, 08:00 PM
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Hi Mos,

2. Does phase matter here?
No, not at all.

3.Again, would phase be an issue here?
Ditto, no.

4,5. Correct

1. Do I need to put a Jumper between "COM" and "L1" as stated below?
Optional. Without the jumper, I don't think the LED will light, but that's no big deal.

2. Can I just jump Terminal "A" to "L1" and also the Neutral from the Basement pump to "L2"?
I wired it that way because I didn't know the 'source' of the AC supply for the pump.
For that reason, I chose to use A and B in order to play it safe and keep the AC supplies separate from each other in case they came from different 'places' (breakers, legs) in the panel.

Currently the way the pump is setup in the basement is that the thermostat makes/breaks the HOT connection to the pump. This means that if I am to follow the below diagram, I would need to run an extra set of electrical wiring which is why I am hoping that I can just jump it on the 8845U itself. Please advise.
I had presumed that there was another relay box running the basement pump, but I believe that you are saying that it's simply a 'line voltage thermostat' ?

If you simply jump A to L1, you would still need to wire the basement thermostat in series with the pump because the thermostat ALSO needs control.

Alternately;

What you could do is wire L2 to the Neut of the pump.

Wire L1 to COM.

Wire N.O. to one side of the basement thermostat.

Wire the other side of the basement thermostat to the H of the pump.

No connection to A or B.

If needed I can revise the drawing.
 
  #16  
Old 12-13-11, 08:31 PM
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Hey Trooper,

Don't forget, I wanted to eliminate the basement thermostat completely and just have the pump run off the upstairs thermostat. Since the wiring schematic has changed and this is not really one of my strong point, I guess the revised diagram would not be such a bad idea.

Thanks
Mosil.
 

Last edited by Mosil; 12-13-11 at 09:45 PM.
  #17  
Old 12-14-11, 03:23 PM
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Why get rid of it? Leave it in place and you can run the basement cooler if you wish...



With this arrangement, BOTH thermostats need to be calling for heat, which makes the most sense to me...
 
  #18  
Old 12-19-11, 09:53 AM
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Trooper,
I connected the unit just as indicated in the diagram and it is working great. Thank you so much for your help with this.

Happy Holidays!

Mosil.
 
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Old 12-19-11, 02:24 PM
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Great! You're welcome!

Have a great Holiday yourself!
 
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