Oil burner works for water, but not for thermostats, please help


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Old 02-02-14, 06:52 AM
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Oil burner works for water, but not for thermostats, please help

Hello. I have 4 zones, one wasn't working, thought water froze in pipe. I bled line and heated pipe. Now flame comes on for hot water, but not for the thermostats. I have all thermostats turned all the way up, tried turning power off, tried reset button. What else can I do? Please help.
 

Last edited by Glenruss; 02-02-14 at 07:16 AM.
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Old 02-02-14, 07:40 AM
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If boiler is up to temp. there's nothing to reset. What do you have for zone valves and what are the tied into
How are the powered. Did you heat up anything else besides the pipe.
 
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Old 02-02-14, 08:24 AM
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Thanx for the reply Spott. The zone valves are electric, 4 each hooked in to a pipe near the boiler. I didn't heat anything but the pipe where I believe water froze in the line. I just took a hot shower. Why would the boiler come on for hot water, but not for the thermostats?
 

Last edited by Glenruss; 02-02-14 at 08:44 AM.
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Old 02-02-14, 08:45 AM
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What kind of zone valves. Taco, Honeywell.
If you're comfortable with electricity you can remove the cover of your boiler control and find the terminals marked TT. these are the terminals where the zone vales finally tie into that turn the burner on for heat.

These terminals are 24v but there is 110v terminals in there also. L1, C1,, are line voltage. DO NOT TOUCH THESE.

Take some needle nose pliers or something to jump across TT in the control. If boiler starts then the trouble is in the zone valve circuit somewhere. Possible. transformer or whatever is powering the zone valves.
They have their own 24v feed for power somewhere. Track your t-stat wiring and find out what's powering them.

Since all 4 don't work I'm thinking it's something there's a common denominator to all.
 
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Old 02-02-14, 08:56 AM
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They are Honeywell. I will try. I am comfortable with and do my own electric work in my house, don't really know control type wiring though. I am going to try your recommendation now. Thanks
 
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Old 02-02-14, 09:09 AM
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I used needle nose, then a jumper wire, nothing. The thermostat is mounted right on the boiler casing. Actually, I just ran back downstairs to try again, make sure I had good contact and it did come on now.
 
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Old 02-02-14, 09:24 AM
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When you jump TT the circulator should come on also. Make sure to check that.
When you jump TT you should have 110v to C1& C2. That's your pump term.
If you have power there make sure your pump is running.

If your pump works then it's in the zv circuit. It's a 24v circuit. Trace the wires from the stat and see what feed them
Its a series circuit. It goes from the transformer to 1 side of t-stat, from other side of stat to term 1 on zv.
Term 2 on zv back to trans. Then 2&3 go to TT on boiler. If you have 4 wires on zv then t-stat circuit the same but 3&4 go to TT on boiler.

You must find 24v source and check for power. With 4 zones you probably have more than 1 transformer or you may have a Taco or Argo 4 zone relay control where everything goes into.
 
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Old 02-02-14, 09:26 AM
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It turned of after a short time, I tried it again, and now it doesn't come on. I traced the wires and the connections all look good. I manually closed a relay under the t t wires (that had started it up before) now it sounded like water was going through the system, so I stopped. should I hold the relay closed?
 
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Old 02-02-14, 09:40 AM
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I tried it, after a minute it came on, and is now on for a few minutes. Earlier my wife may have turned on the hot water while I was jumping the t t terminals.
 
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Old 02-02-14, 09:53 AM
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I tried jumping the t t terminals again. it didn't work. I manually held that relay closed again, water flowed, then the boiler started again. Would it be ok to manually hold (using something) the relay closed so some I get some heat in the house?
 
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Old 02-02-14, 10:27 AM
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Sorry to jump back and forth, just have to run up here then down to try things. Anyway, jumping the t t terminals defiantly doesn't work. there is power and the pump is working. There is only two wires on the transformer, and no others. Holding the relay closed is working. Could it be the relay, or the transformer I need to replace?
 
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Old 02-02-14, 11:26 AM
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Do I need a new aquastat?

Hello. when I jump the t t terminals the boiler does not fire up. I have to manually close the relay underneath to get it to fire. It does fire by itself when I turn on the hot water. It wont fire for the thermostats (they are set way above room temp.).
 
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Old 02-02-14, 11:44 AM
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Should I try replacing the transformer, or the aquastat?
 
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Old 02-02-14, 11:48 AM
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Also is it dangerous to have the relay manually closed (as that's what I'm doing now) so that I can have heat? Thanks for any help that you could give.
 
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Old 02-02-14, 11:56 AM
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Do you own a multimeter and know how to use it?

If you do it makes sense to check a few things before dropping a dime on a new aquastat, but if jumping the TT terminals does not fire up the boiler, it's a pretty good bet that the aquastat is bad.

Also is it dangerous to have the relay manually closed (as that's what I'm doing now) so that I can have heat?
No, not really... what it amounts to is a continuous call for heat. As long as the HIGH LIMIT control in the aquastat is functioning properly, that will still function as a safety control. Just don't 'bypass' any of the safety controls.

Of course, if you forget and leave it on, the house will overheat... but you'll know that soon enough!
 
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Old 02-02-14, 12:14 PM
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Thanks NJ Trooper. I don't have a multimeter anymore. I figure it's the aquastat, but don't want to replace it just to find out that's not the problem. is there another way to test it?
 
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Old 02-02-14, 12:23 PM
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Also the flame shuts off after a while, even though I still have the relay forced closed, and it sounds like water is running through the system. Is that what it's suppose to do?
 
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Old 02-02-14, 12:30 PM
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When you say the circulator works you mean when you hold the relay in correct. If you don't hold the relay in the pump doesn't work. Is that right.
By holding in the relay it's just as though your calling for heat. By holding that in you may be overriding the high limit also and the boiler will not shut off.

By jumping TT you bypassed the zv circuit. If it didn't work then there is something wrong with the control.
Possibly the transformer in the control or the circ.relay.

Something that may be safer, since you know electricity, you can take C1 & C2 off the control and wire it to a 110v source. This will give you constant circulation and your t-stat would open the zone valves when they called for heat.
The burner would cycle as it would for hot water.

Understand, this would be very temporary until you replace the control.
I did understand you correctly when you said you got your hot water from a tankless on the boiler
 
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Old 02-02-14, 12:40 PM
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Glen,
I responded to your other thread but since your high limit does work you can ignore it.
It sounds like it's either your transformer in the control or the circ relay itself but either way it looks like a new control.

The boiler shuts off because its reached its limit like it does for hot water. That's a good thing.

Good Luck,
 
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Old 02-02-14, 01:02 PM
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Thanks again Spott. So should I try to replace the transformer first (I think would be cheaper) before replacing the aquastat?
 
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Old 02-02-14, 01:10 PM
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or do you mean the transformer thats in the aquastat? And should I still put temp. power? I will get, hopefully the local pluming supply will have it, tomorrow.
 
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Old 02-02-14, 01:46 PM
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Spott meant the transformer inside the aquastat box... I'm sure you could 'jury rig' something, but what Spott was saying is that the coil on the relay itself, the one you wedged closed, could also be bad. Without testing with a meter, can't know which it is, but either way, I think you're in for a new aquastat.
 
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Old 02-02-14, 01:50 PM
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ok thanks, I'll replace it tomorrow
 
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Old 02-02-14, 01:58 PM
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Glen,
I was talking about the transformer and relay in the aquastat as trooper pointed out.
The transformer for the zv's is working fine.
No need for temp power because your high limit is working fine.
 
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Old 02-02-14, 02:21 PM
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Glen, I merged your two threads since they are both basically dealing with the same issue.
 
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Old 02-03-14, 06:24 AM
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Thanks NJ Trooper, and Spott for your help. Now I need to find the right Aquastat. The one I have is a Triple Aquastat Relay Type L8124A, C L8151A. I can't find the exact type, but can find L8124A1007. How can I find out if that is the right one?
 
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Old 02-03-14, 06:54 AM
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Honeywell does not make it easy to determine what the differences are... that four digit 'flavor' number that they tack on.

In general, all the 8124A are the same PHYSICALLY... (well, almost, they call some vertical and some horizontal, but basically this refers to the direction of the nameplate on the cover)

The DIFFERENCES are in the temperature range and the fixed differential range.

These are the specs that are of interest... you want a temp range with your interest relatively in the center of the range. Like 140 to 220 or so...

The DIFF on various units is 'fixed' on the HIGH side, models can range from about 8F to about 15F fixed high diff. The LOW on yours is of course adjustable. I would opt for a 15 Diff if it's available.

There are modern electronic a'stats that will replace yours and are fully adjustable and 'universal', for example, the Honeywell L7224U or the Hydrostat 3250... and in the same price range too.
 
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Old 02-03-14, 07:34 AM
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Great info.! Thanks again. Would you recommend a new electronic astat, or would it be cheaper and easier to replace it with the same type, once I find one with the right differential?
 
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Old 02-03-14, 11:11 AM
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How about a soldering iron? Own one? Know how to solder PC boards? I'm betting that if you pull the PC board out you will find a cracked solder connection at one or more of the relay connections. It's a pretty common failure mode... seems like when HW started outsourcing production and the advent of lead free solder, the quality of the soldering job has gone to h-e-doublehockeysticks.

I personally would probably go with a newer model, such as:

L7224U1002 - Honeywell L7224U1002 - 120 Vac Oil Electronic Aquastat

Or:

48-3250 - Hydrolevel 48-3250 - Model 3250 Fuel Smart Hydrostat (Temperature Limit, LWCO, & Boiler Reset Control) for Oil Boilers

But I'm partial to electronic stuff...
 
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Old 02-03-14, 11:37 AM
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I actually do have a soldering iron in my garage somewhere and will try it. I didn't think of it, as you said about soldering jobs. It's been years but why not try it? If it doesn't work I'll go back to shopping for the a'stat.
 
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Old 02-03-14, 12:02 PM
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I think I'm going to order one of the models you suggested. I'd hate to remove the board and then not have something ready to take it's place if I damage it. Will the wiring be the same on the new models?
 
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Old 02-03-14, 12:57 PM
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Will the wiring be the same on the new models?
It's going to 'look' a little different, but otherwise all the same functions.

Your existing unit has line voltage wiring to ( L1 & L2 - AC INPUT ), ( B1 & B2 - Power to burner ), ( C1 & C2 - Power to circ ), and ( T T - thermostat input ).

The 7224 has all these, but in different locations, labeled the same.



The 3250 also has the same labeled terminals:



The only trouble you MIGHT run into is if the wires are too short to reach the new terminals...
 
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Old 02-03-14, 02:04 PM
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I'm going to order the 7224. do I need anything else for mounting or anything?
 
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Old 02-03-14, 02:14 PM
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Nope. Mounts right to the existing well.
 
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Old 02-03-14, 02:29 PM
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Ok, thanks again. I'll let you know how it goes. Pexsupply seems to deliver pdq, from the reviews I read.
 
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Old 02-03-14, 02:37 PM
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Yes, they do. If it's one of the 'fast track' items you'll have it in like 2 days UPS ground, in most cases.
 
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Old 02-09-14, 09:46 AM
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Hi, I just put in the new A'stat!

Hi N.J. Trooper and Spott. Thanks for all your help. I got the new 'stat days ago, but had to go out of town for a few days, got back last night and installed it this morning. Seems to be working well. But I'm not sure what to put the settings at. Can you give me some recommendations? And it says to set the thermostat anticipator to 0.1 amps, but I don't know how to do that. Can one of you guys continue to help me out?
 
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Old 02-09-14, 10:12 AM
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Since your thermostats are controlling zone valves, there is no need to concern about the anticipator setting. Most newer thermostats don't even have an anticipator setting... if yours do, they should be set to what the ZONE VALVES draw, not what the aquastat draws...

You should be 'good to go' now.

Have you waded through all the various settings yet?

What did you set the temps at?
 
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Old 02-09-14, 10:24 AM
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It had been set at 180-160 on the old one. I set this one at 170-150 to try. and 15-10. for the H-L Diff. How does that sound to you?
 
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Old 02-09-14, 10:33 AM
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I would put the HIGH at 180 with a 20 DIFF. This will make for longer cycles, but longer time OFF also. It will tend to reduce short cycling.

Yes, try the LOW at 150 and also with a 20 DIFF. The lower you can run the LOW that is consistent with adequate hot water to the home, the better. If you have no problems with enough hot water, try 140 even... leave DIFF at 20.
 
 

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