New aquastat L8148E, no voltage to burner


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Old 02-07-19, 05:53 AM
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New aquastat L8148E, no voltage to burner

I just finished replacing my aquastat L8148E, vent damper and 120VAC to 24 VAC transformer. T, C, L and vent damper are all getting power, but the burner is not. Iíve triple checked all my connections. Any suggestions???
 
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Old 02-07-19, 08:09 AM
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hi-

Iím not one of the experts here, they will probably be along. But is the damper connected to the 8148 via a Molex plug? (That connector for the damper is optional, all models do not have it.)

It looks like the circulator would always run on a call from the thermostat, but NOT the burner if there is a problem with the damper.

I think on the 8148e the burner also runs through High Limit, so if the High Limit is defective I think you would find that the circulator would run but not the burner. I think there is a set of relay contacts for the burner and a set for the circulator. So if the burner contacts are bad (dirty etc.) I think the circulator could run Ė but not the burner.

One of the experts will be along Iím sure.
 
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Old 02-07-19, 08:57 AM
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Not an expert either bug just getting power to the vent damper isn't enough. Is it opening and closing with a heat call? If not fully open then it is supposed to cut out the burner. How is the damper connected if not through the Molex?
 
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Old 02-07-19, 10:53 AM
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Do you have 24V at B1 & B2 that will power the gas valve. Check your voltages to pump, C1 & C2 and L1 & L2. Pump and L1 & 2 are 120V and B1 & 2 are 24V.

If no power to any of these terminals it's not the control. If you have power to L1 & 2 and not the others check your stat. 24V when not calling, 0V if calling and trace from there. It's a series circuit so if power is stopped anywhere along the line everything beyond that point will not work.
 
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Old 02-07-19, 01:09 PM
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Thanks everyone for the replies. The damper is connected via Molex plug, and both the damper and wiring are all new. The damper was installed in the open position, so it hasnít cycled at all.
I have power at L1, L2, C1 and C2. No power showing at B1 or B2. I can press the relay down and the circulation pump starts pushing water, but that is all that happens. Nothing seems to be sending a signal to fire. Iíve tried cranking the thermostat and still nothing. I also tried a new thermostat, and that didnít do anything either.
Not sure if this matters or not, but I also have a Low Water Cutoff. Maybe Iím just low on water? How do I even check this?
 

Last edited by Rebeccajoyd; 02-07-19 at 02:03 PM.
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Old 02-07-19, 03:19 PM
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Your LWCO could very well be the problem It is part of that series circuit. With gas it's most likely 24V so check it with your meter. You can jump across it to see if it turns the burner on. In order to start the burner you must get power to B1 & B2. What brand of LWCO do you have. Pics would be good if possible.

Your control is a high limit control which means on a call for heat the pump and burner should start. Try putting a jumper across T & TV and this eliminates the control being bad if it starts and your problem is somewhere between the stat and the control.

You said your vent damper is open. Try shutting off your stat and it should close. If it doesn't you have a problem at least there.
 
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Old 02-07-19, 04:39 PM
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Troubleshooting is best conducted in a thorough, logical manner. One approach, in this case, is to start with a voltmeter at where voltage is expected, but is now zero. Work upstream in the circuit until you first find voltage. That pinpoints the problem.

The other way is start where there is 24V in the circuit, and work downstream until the voltage is zero - that pinpoints the problem.

The third way is to follow hunches - that may work.
 
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Old 02-07-19, 05:27 PM
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Thanks Spott and gilmorrie.
I have to correct myself - I thought I had power to L1, L2, C1, C2, T1 and T2. That wasnít the case.
I just rechecked everything with a voltmeter. Starting at the transformer with the thermostat off, I have 24V coming out of the transformer. I have 24V at the terminal on the LWCO. Once I get to T and Tv I have 0V. Starting at L1, I have 120V. C1 and C2 have 0V. B1 and B2 have 0V.

With the thermostat on and turned up to 85, everything reads the same.

When I jumper to take the LWCO out of the circuit, I have 24V @ T, plus the 120V @ L1. Still 0V at B1/B2 and C1/C2. Nothing turns on. When I jumper T and Tv it doesnít change anything.

My LWCO is a Safgard 24 SV. My damper doesnít close on its own with a change in the thermostat.

Trying to figure out how to add pictures here....
 
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Old 02-07-19, 06:04 PM
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Here is a picture of the entire system and a close-up of the LWCO. On the LWCO, the lines from the transformer are attached on the left 2 leads, the leads on the right go into the relay box, are spliced with the wires from the thermostat, and then go to T and Tv. Not sure if this is the correct set-up, just left it the same as it was on the old relay.
 
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Old 02-07-19, 06:55 PM
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From your transformer you are going to 1 & 2 on the LWCO so you should have 24V there. You have another wire to P1 & P2 and then your stat wire which are connected in the box. Trying to see how you have them connected. Do you have power to P1 & P2 on the LWCO.

They want your LWCO fed first and then go through the controls in a series circuit.
 

Last edited by spott; 02-07-19 at 07:41 PM.
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Old 02-07-19, 07:31 PM
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A question. Do you know the switch is off above the transformer.

With nothing connected to T & TV in the control and with the power on see if you have 24V at those terminals. If you do this is telling you they are using transformer in the control to power the stat circuit which means your LWCO is using 2 sources or power which is fine and long as your connections are right.

One other thing I noticed is your gauge reads 0 pressure in the boiler. Did you refill after the new installation. You want 18-20 but at least 12 which the feeder comes factory set at.
 

Last edited by spott; 02-07-19 at 09:36 PM.
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Old 02-08-19, 03:06 AM
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I have been turning the power off when Iím not tinkering and taking voltage readings. But thanks for pointing it out - sometimes we overlook the obvious when working through a problem!

Wtih the power on and nothing connected at T and Tv, I have no voltage at the terminals for T and Tv. I have 24V at 1 in the LWCO, and 0V at P1.

My boiler hasnít run since last Tuesday morning, and the pressure has been at 0 since it quit last week. I didnít add any water to the system.
 
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Old 02-08-19, 04:39 AM
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Hi, here is a link to the LWCO that may help, your control appears to be setup as B 2 separate supplies. remove wires from P1&P2 and with an Ohm meter test between the 2, under normal conditions they should be closed.
Where are the conductors on terminals 1&2 connected? You must have 24 VAC on those terminals.
You can also jump P1&P2 and see if the boiler fires up, if it does the LWCO is open, possible low on water, if it doesn’t problem is elsewhere.
What is the mdl# of the vent motor?
https://hydrolevel.com/wp-content/up...1515-final.pdf
Geo
 

Last edited by Geochurchi; 02-08-19 at 04:55 AM.
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Old 02-08-19, 09:11 AM
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OK Ė you can see who has too much time on their hands Ė but does this diagram represent the configuration? Seems like the LWCO was put upstream from the 8148E and not in front of the burner. Seems like it would not be as safe this way.

But I certainly can be misinterpreting how the system is really configured.

But, regardless, it seems to me that if there is no voltage at T-TV when the 8148E is powered on (i.e., has power at L1) and nothing is connected to T or TV, then something must be wrong with the 8148E. The 8148E transformer or something else in the unit must be bad. Or is that not correct?
 
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Old 02-08-19, 09:38 AM
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Earlier you said that the vent damper was getting power?
Make sure the jumper between Z and W is installed.
 
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Old 02-08-19, 02:02 PM
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You all are great - thanks so much for taking the time to shoot suggestions my way!

Geo - thanks for the link. I had searched on hydrolevel to make sure everything was set up properly. The diagrams match what is on the inside cover of the LWCO, and I think it's connected properly. I hadn't changed anything here, and the boiler used to run fine before the relay went bad.
I checked P1 and P2 per your direction and the circuit is closed. Terminals 1 and 2 are connected directly to the transformer and I have 24VAC there. Jumper across P1 and P2 doesn't do anything.
The damper is a GVD-6.

zoesdad - your diagram is correct.
The LWCO was installed upstream from the 8148E. Not sure why it was done this way - I've only been in the house for 1.5 years so I'm just rolling with what they had.
There is 24VAC at terminals 1 and 2 on the LWCO, coming right from the transformer.

Astuff - I was mistaken - I thought I had power to the damper Molex, but when I walked through readings again last night I got nothing. There is a jumper between Z and W.

I am seriously wondering if the new L8148E that I installed is bad....
 
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Old 02-08-19, 02:12 PM
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Measure between L1 and L2 on the Aquastat - do you get 120 volts there?

L2 looks like the wire is going counterclockwise which caused me to think to go back to the basics.
 
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Old 02-08-19, 03:16 PM
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I do have 120V between L1 and L2.
 
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Old 02-08-19, 03:17 PM
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Next check for 24v between Tv and Z - that is the other side of the transformer.
 
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Old 02-08-19, 04:36 PM
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I have no voltage when I check Tv and Z.
 
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Old 02-08-19, 04:46 PM
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So Aquastat's transformer is not working.
 
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Old 02-08-19, 05:02 PM
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Well that is frustrating, since itís a brand new unit. Thanks for the suggestions on what to check everyone. Ordered another new unit, due to deliver Monday. Fingers crossed this one will work.
 
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Old 02-08-19, 05:38 PM
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You are always going to have power at L1 & L2. The pump and burner terminals do not get powered until there is a call for heat.

You are getting 24V to the LWCO at 1 & 2 because of the separate transformer. To get power to P1 & P2 you have 2 choices. You either put a jumper from I to P1 or you need another separate 24V source.

The way yours is wired is 2 separate power sources. The separate trans. is for 1 & 2 and they are using T & TV as the other source but in your case you are not getting any voltage to T & TV so that is why you don't see voltage at P1 & P2.

You said it worked previously with this wiring arrangement and it looks like it should. With power going to the aquastat such as L1 & L2, if you jump T & TV the other terminals should get power.

Did the molex connector on the new control come with a jumper. If so disconnect your molex connector and use jumper or just jump it out for now to see if that does anything.

I believe that T & TV should have 24V as soon as you connected L1 & L2 but you said it doesn't so either it's defective or your current wiring is wrong but you said it worked.

If you still have your other control can you bench test this. Put 120V to L1 & L2 and then see if you get 24V to T & TV on the old one. I think you should get 24V without the molex jumper but if not just jump.

When you jump the stat terminals that relay should open to start pump. If not you may have gotten a bad control. The current wiring you have is telling me your old one worked as described with T & TV being powered when line voltage is applied to L1 & L2.

Your wiring goes from TV-P1-P2-STAT-STAT-T. Series circuit all based on T & TV having 24V to start.

Sorry for all this. Didn't see others when I started.
 
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Old 02-09-19, 04:11 AM
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Hi, terminals 1&4 on that damper motor must have 24 VAC when damper is open, 2&3 are the control circuit. This pic may help you understand how the 24 VAC is supplying TV-Z in that control from L1 and L2.

Geo
 
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Last edited by Geochurchi; 02-09-19 at 04:28 AM.
  #25  
Old 02-09-19, 09:53 AM
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Note 3 below that schematic says:

AFTER VENT DAMPER IS PLUGGED INTO L8148E, FUSE BLOWS WHEN THERMOSTAT FIRST CLOSES. AFTER FUSE BLOWS, L8148E OPERATES ONLY WHEN VENT DAMPER IS CONNECTED.
But it seems to me, looking at that schematic, even without the damper, a call from the thermostat would still cause the circulator to run as long as the factory set W-Z jumper is not removed and there is a call for heat from the thermostat.

And with or without the damper you would get 24vac across T-TV with the thermostat out of the picture (as long as you have power at L1).

So it seems to me if you get nothing at C1 with a call from the thermostat, and nothing at T-TV with the thermostat disconnected, then there must be something wrong with the 8148E independent of any problem with the damper. Could be wrong, I do have my problems readings those schematics. But that’s the way it looks to me.

WHOOPS!!! I need to look at that fuse part a little better. Maybe that can kill the entire unit.
 

Last edited by zoesdad; 02-09-19 at 10:14 AM. Reason: added the "WHOOPS...
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Old 02-09-19, 10:58 AM
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I believe the fuse blows so that if you try putting the original jumper back the burner won't work but the circulator still will run. It is not very effective for the persistent but may prevent another Darwin Award winner.
 
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Old 02-09-19, 01:18 PM
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That's what I thought when I looked again.

(Yep, Darwin Award - lol)
 
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Old 02-11-19, 03:11 PM
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Sorry all for the radio silence. Taking a break from troubleshooting for th weekend, plus I ordered another aquastat out of frustration. Aquastat came into today, I hooked it up and BAM! I have heat!!!

Gotta love when replacement parts donít work out of the box. SMH... But Iíve learned a lot, so weíll just count this as a big (cold) learning experience.

You all are great - thanks again for passing along your words of wisdom!!

rjd
 
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Old 02-11-19, 03:52 PM
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Thank you for the update.
 
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Old 02-17-19, 01:42 PM
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Ok, back at it again here. My replacement aquastat powers things up just fine, but the relay started sticking (making an awful LOUD buzzing sound). So I had Supplyhouse send me a replacement (this is #3 for anyone keeping track). After a day it did the same thing!

Again, itís hooked up the same way. All connections are solid. Vent damper works properly (although Iíve tried setting it to Hold Open in case that was the problem). Iíve tried adjusting the water temp between 160-180 (although 160 is too low to get my house to stay at 70 degrees).

Any ideas/suggestions?
 
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Old 02-17-19, 02:35 PM
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If I can make a suggestion. Temporarily eliminate your LWCO. When you wire up your new control see what your voltage is across T&TV. It should be 24V. With your B1&B2 & C1&C2 connected see if get any buzzing. If not then just connect your stat wire to T&TV without the LWCO. Separate those wires in the control and wire stat only and check for buzzing.

It is safe to run with LWCO. It's just an added feature. See how the control acts. I'm thinking possibly too much low voltage for some reason is being sent to T&TV ruining your control transformer. If it starts buzzing at this point disconnect your molex vent damper. If you a jumper came in the molex use it and set the damper to stay open.

I doubt if the controls are bad. My guess is it's something in the wiring. Hook things up one at a time until you hear buzzing and immediately shut down and disconnect wire that started buzzing.
 
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Old 02-17-19, 07:53 PM
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Some thermostats (notably Nest) cause sticking/buzzing with heating systems. Does the Aquastat make noise with a heat call, without a heat call, or both?

If noise without a heat call disconnect T and Tv to see if noise stops.
If noise with a heat call try directly jumpering T and Tv to see if noise stops.
 
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Old 02-18-19, 09:37 AM
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Ok, here is what I found last night. I flipped the electrical on, vent damper opened, burner fired up. Voltage readings were Tv - 23.5, T- 22.3, 23.6 at P1 and P2, nothing to 1 and 2 on LWCO. Just to clarify, 1 and 2 are hooked to the transformer, P1 to Tv and P2 to the thermostat. The relay started to buzz after it ran for a minute. I switched the damper to Hold Open, flipped the power off, pulled the Molex for the damper and put the jumper in. Powered the system on and the buzzing continued. I ended up moving the wires from the LWCO around when taking voltage readings and that movement stopped the buzzing. Hmmm, seemed like those are the culprit. I disconnected the LWCO, hooking the transformer directly to Tv, with the thermostat still connected to T. The system fired up with no buzzing relay. I adjusted the water temp up and down to get the system to call for heat and then turn off a few times. All seemed good. Tv had a Coltage reading of 23.6. BUT, when I checked T it had a voltage reading of 45. It was running well, so I let it run a while and it tripped my breaker eventually. And I think it fried the new transformer I put on last week because Iím not getting any voltage out of the transformer. But if I push the relay in manually the system calls for heat.
Was I incorrect in assuming the thermostat white wire would stay on T, and the transformer white wire would got to Tv, with the red wires from the two spiced together?
 
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Old 02-18-19, 10:08 AM
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The mistake you made was using that external transformer at all. You did not need it with the one in the aquastat supplying the 24V needed to run the system.

By using that external transformer you doubled the voltage to the T-TV terminals, blowing the transformer. That is why it was suggested to eliminate the LWCO. It was to eliminate that external transformer which was believed to be the culprit because of the way it was wired.
 
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Old 02-18-19, 10:40 AM
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Ahhhh... gotcha. External transformer is only needed with the LWCO, and if that is removed the thermostat hooks right to T and Tv, and the aquastat will power it. Iíll give it a shot when I get home!

Thanks spott and Astuff for sticking with me... Fingers crossed!!
 
 

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