Another aqua stat question


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Old 10-26-14, 05:43 PM
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Another aqua stat question

I have a slant fin v90. When I was replacing the burner access panel with the boiler running and burning, I touched the rollout switch with the panel, saw a quick spark, and then the inducer quit and the burner shut off. Now the circulation pump runs but no start of the inducer. What did I screw up?
TIA
Paul
 
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Old 10-26-14, 07:26 PM
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You could have damaged the rollout switch... or worse, shorted the 24VAC to ground and damaged the ignition control.

If the circulator runs it's not the transformer in the aquastat.

Do you own and know how to use a multimeter?
 
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Old 10-26-14, 07:49 PM
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Yes I have a multimeter. Looking at the process flow chart, I was thinking it wasn't the ignition control because I never get the inducer to run. High limit contacts or switch first I thought...
 
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Old 10-26-14, 07:54 PM
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I see what you mean.

The inducer should run even if the rollout switch is open.

When the system is calling for heat and the circulator is running, what voltage do you have between B1 and B2 ? should be 24VAC.
 
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Old 10-26-14, 07:58 PM
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I'll have check in the morning, thanks much for your help!
 
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Old 10-26-14, 08:05 PM
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If you have no voltage between B1 and B2 when the thermostat is calling for heat and the circulator is running, then the problem is with the aquastat, either the K1 relay contacts or the contacts in the High Limit switch.

You can TEMPORARILY! test this theory by jumpering from the "Z" terminal to the "B1" terminal.

If the inducer starts and the burner fires, the problem is with the aquastat.

REMOVE THE JUMPER! With that jumper in place, you are operating without the HIGH LIMIT in the circuit... and this would be dangerous if you left the jumper in place.

If the inducer does NOT start with the jumper, remove the RED wire from B1 and set your meter to OHMS and measure from B2 to the disconnected RED wire to the inducer.

You should measure somewhere around 80 to 100 ohms or so... don't know the exact, but you should measure something around there.

If you measure OPEN then it means the inducer relay is shot.
 
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Old 10-27-14, 05:25 AM
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Hi Paul,

Is your L8148E aquastat the model with the jumper plug for plugging in a motorized flue damper?

Do you know the 4 digit suffix number of the aquastat?
 
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Old 10-27-14, 08:00 AM
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Ok a jumper from Z to B1 started the inducer! Would monkeying with the setting on the high switch help you think or time for a new aqua stat?
Thanks again,
Paul
 
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Old 10-27-14, 09:00 AM
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Would monkeying with the setting on the high switch help you think or time for a new aqua stat?
I dunno... It can't hurt.

I find it hard to believe that a momentary short to ground would be enough to take out the contacts on the limit or the relay...
 
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Old 10-27-14, 09:01 AM
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What exact model of aquastat do you have on the boiler? Include the 4 digit suffix.

Do you have the plug for the vent damper on that aquastat? (If it's a 1273 you do not.)

I think it's an L8148E 1273 which is discontinued and replaced with L8148J 1009.

http://www.supplyhouse.com/Slant-Fin...rol-L8148E1273

replaced by:

http://www.supplyhouse.com/Slant-Fin...ll-L81448J1009

There are others you can use as well:

http://www.supplyhouse.com/Hydroleve...or-Gas-Boilers
 

Last edited by NJT; 10-27-14 at 09:24 AM.
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Old 10-27-14, 09:10 AM
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I'm not at home for a few hours but I will check. There is no flue damper, but I think I remember a jumper on there.
Thanks again!
 
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Old 10-27-14, 09:12 AM
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Wanna determine whether it's the K1 or the High Limit that's bad?



If you measure from B2 to the B wire on the high limit you can determine if the 24VAC is getting through the K1 relay. If you have 24VAC there when there is a heat call, the K1 is OK.

At the same time, if you have nothing on the R terminal, the High Limit switch is your culprit.

Unfortunately, either one will likely mean a new aquastat.
 
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Old 10-27-14, 01:48 PM
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So, the last 4digits are 1257, and it looks like it has been replaced by the 1265. Measuring from B2 to B I nothing, so I guess it's the K1 relay? Where is this relay, on the back of the circuit board? I only see one relay (I think) on the front. In any case I think I'm going to replace the aqua stat. Thanks again!
 
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Old 10-27-14, 02:20 PM
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I really don't understand how that momentary short could have taken out the contacts on that relay. Makes no sense. But I guess it is what it is.

Where is this relay, on the back of the circuit board? I only see one relay (I think) on the front
It's on the front, there is only one relay. It has two "poles". One pole switches the circulator on, the other sends voltage to the gas valve through the rollout switch, after the inducer blower switch proves that the inducer is running.

Seriously think about the HydroStat 3200 as a replacement...

48-3200 - Hydrolevel 48-3200 - Model 3200 Fuel Smart Hydrostat (Temperature Limit, LWCO, & Boiler Reset Control) for Gas Boilers
 
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Old 10-27-14, 03:13 PM
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Ok thank you, I will take a look at the Hydrolevel. I don't understand how the contacts on the relay could be shot either, there is certainly no visible evidence of damage and the relay seems to pull in strong. Anyway thanks again, for patiently answering my questions!
 
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Old 10-27-14, 06:16 PM
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If you have a soldering iron and are able to solder printed circuit boards (ELECTRONIC SOLDER!, not ACID CORE solder), what you can do is inspect the contacts on the solder side of the board for cracked solder joints and reflow some solder.

It's just possible that you had a solder joint that was getting ready to fail and that momentary short circuit was the straw that finished it off...
 
 

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