Icesaylor, Mark Eatherton, Timmy McElwain..............

Alan (California Radiant) Forbes

.I need some of you smart guys on this one.



I went out on a "no heat" call this afternoon on a Hydrotherm HC-250 atmospheric boiler.  There was no spark on a call for heat and I tested for 24 volts at the ignition control module (ICM)  - almost zero voltage.  So I checked the safety train and everything checked out except the flue damper which I bypassed - nothing.  Eventually, I bypassed all the safetys and took 24 volts directly from the Honeywell L8148E aquastat relay to the ICM - still nothing. When I meter the two 24 volt terminals on the ICM, it registers a couple of volts, but when I pull one of the leads off and test again, I get 24 volts.



Where is the voltage going when I connect the ICM (I tried 3 of them)?  Thinking there may be a short in the Smart Valve, I unplugged the leads, but still get the same results.  The transformer in the aquastat relay pulls the relay in smartly, so it's hard to imagine the transformer is weak.



Any ideas, fellas?

NYplumber

hey, i wasnt mentioned

I'm only kidding.



Check for 24vdc on the aquastat relay.

furnacefigher15

open wire

You have an open wire on the "common side"



When a load has voltage in and out , but can't complete the circuit, it will read as 0.



Same as removing the C terminal from transformer, Circuit cant complete.



A load can only consume power if the circuit is complete.



when your meter says 24 v across a valve what that means is that the valve is consuming that 24 v



Other possibility is an under powered transformer ( may be in aquastat) that looses voltage once a load is present

Alan (California Radiant) Forbes

That's what all the dots are about

.......................as in all the other smart guys out there.



So you are saying that once there is a load, the line voltage drops off?  I have no problem with that except it's strong enough to pull the relay in to start the circulator.

JStar

RE

Try removing the ignitor cable and rechecking voltage. Sometimes a faulty or grounded ignitor will draw too much power from the module and cause a voltage drop in the circuit. Also check 24V with and without load.

Mark Eatherton

I concur with these guys Alan...

Test the transformer and WIRING under a true load condition..



Although you may "see" 24 volts on you DVM, it's a false 24 volts because under a load, it goes away. You may have to test individual circuit branches on their own in order to isolate it. Look for suspect spade/crimp connectors. I have also found that it helps to work in the dark. Literally. Close off the light, and wiggle the wiring and look for a small arc. I've spent more than one night on the floor of a boiler room having a stare down contest with a wiring harness waiting for a spark or failure. In most cases, it was a crimp/spade connector that had given up the ghost.



Best of luck.



ME

Tim McElwain

Alan what

is the model of the module? What is the model of the relay? You stated you have a SmartValve what is its number?



With this I can walk you through a checkout.



A suggestion in the meantime is to place your one meter lead on the "C" terminal of the transformer often depending on the aquastat relay this is "B2" Then systematically using the other meter lead see what you have. With say B1 and B2 with no load (wires disconnected) what do you have (should read 24 volts) with a call for heat. Now connect up your load and see what you get. If the voltage drops down then your problem is after the relay on the connected controls. Keep in mind if this is a Generation I or II SmartValve you have an uninterrupted 24 to SmartValve so go to 24 volt Hot and ground on SmartValve and if you read full 24 Volts then initiate a call for heat. Move the meter lead to the interrupted 24 to SmartValve if voltage drops the problem is the SmartValve.



Get me all those numbers and I will get back to you.

Alan (California Radiant) Forbes

Details

Thanks for the suggestions, guys.  I'm going out there later today and will take this further.



Honeywell S8600 universal ignition control module

Honeywell L8148E aquastat relay

SmartValve?



The leads on the SmartValve are

PV

MV/PV

MV



If the problem is the SmartValve, shouldn't I be able to unplug it from the ICM and get a spark or at least a stable 24 volts at the ICM?  And the same with the igniter, i.e. unplug it to get a stable 24 volts?



Thanks for your help!

Tim McElwain

Reply

Honeywell S8600 universal ignition control module IF YOU HAVE 24 VOLTS TO THE MODULE YOU SHOULD HAVE SPARK. NO 24 TO MODULE THEN GO TO 24 VOLT SOURCE WHICH I IMAGINE IS B1 AND B2 ON THE RELAY. NO 24 THERE THEN THE RELAY TRANSFORMER IS BAD.



DO YOU HAVE A VENT DAMPER ON THIS BOILER?





Honeywell L8148E aquastat relay THE LETTER "E" DENOTES THAT THIS RELAY PUTS OUT 24 VOLTS FOR A 24 VOLT SYSTEM. THE 24 COMES FROM THE TRANSFORMER IN THE RELAY."B1" AND "B2" ARE THE SECONDARY OF THAT TRANSFORMER WHEN A CALL FOR HEAT FROM THE THERMOSTAT TAKES PLACE. THAT TRANSFORMER ALSO OPERATES THE RELAY COIL TO BRING IN "C1" AND "C2" FOR THE 120 VOLT CONTACTS FOR CIRCULATOR. IT COULD BE JUST ENOUGH JUICE ON THAT TRANSFORMER TO OPERATE THE SMALL COIL FOR CIRCULATOR BUT NOT ENOUGH TO HANDLE THE GAS VALVE ALSO. THE INTERNAL COIL AND THE GAS VALVE ARE WIRED IN PARALLEL ACROSS THE SECONDARY OF THE INTERNAL TRANSFORMER IN THE RELAY.



SmartValve?



The leads on the SmartValve are

PV

MV/PV

MV

THAT IS NOT SMART VALVE THAT IS A STANDARD 24 VOLT GAS VALVE FOR USE ON INTERMITTENT SPARK IGNITION. ON A CALL FOR HEAT RELAY POWERS THE MODULE, MODULE SENDS 24 VOLTS TO PV MV/PV (GROUND) BURNER GROUND ON THE MODULE, 24 VOLT GROUND AND MV/PV ARE ALL GROUND (THE"C' TERMIAL ON THE TRANSFORMER OR IN THIS CASE B2). THE MODULE SHOULD SPARK AND LIGHT THE PILOT, PILOT PROVES MICROAMPS AND THEN POWER SHOULD COME FROM MV - MV/PV TO GAS VALVE AND VALVE SHOULD OPEN AND BURNER LIGHT.



FOLLOW THE PROCEDURE THAT I GAVE YOU BY CONNECTING ONE LEG OF YOUR METER TO "B2" AND LEAVE IT THERE AND THEN JUST FOLLOW THE 24 VOLTS. COMING FROM "B1".

If the problem is the SmartValve, shouldn't I be able to unplug it from the ICM and get a spark or at least a stable 24 volts at the ICM?  And the same with the igniter, i.e. unplug it to get a stable 24 volts?

YES IS THE ANSWER TO THAT QUESTION, BY PROCESS OF ELIMINATION WORK BACK TOWARD THE TRANSFORMER IN THE RELAY.

Plumdog_2

Alan......

You mentioned looking for 24 volts dc...I think you want to look for 24 volts AC!

Alan (California Radiant) Forbes

Turns out.............

it was the aquastat relay (Honeywell L8148E) and I replaced it with an L8148J.  But before I got it working, I couldn't get 24 volts to the safety string and I thought I had a bum control.  I called Bruce,  my supplier and he reminded me that this was a universal control, so I checked the instructions:



http://customer.honeywell.com/techlit/pdf/60-0000s/60-2278.pdf



and realized (finally) that I needed to jumper terminals Z and TP in order to get 24 volts to the secondary and after I did the jumpering, IT FINALLY WORKED!!!!!!



Thanks to all of you: Timmy, ME, NYPlumber, FurnaceFighter, JStar, Plumdog and finally Bruce who asked me if I fried a J. 



The owner has heat to his house and he doesn't need to canel their holiday dinner with all his mispuche and machatunim.

Tim McElwain

Every truck needs an L8148J

from Honeywell, by the way White Rodgers has a similar control that is a Universal replacement.



Alan a story about the jumper needed for 24 volts on the "J" control. When I was with the gas company I was responsible for 106 service personnel so all kinds of calls from them would typically come to my office. A large majority of them went like this - "Hey! I installed one of them "J" controls you talked about in class and it ain't working!" I would say to them "JUMPER" and I would hear a click as he hung the receiver on the other end.



Have a Merry Christmas Alan glad we could all be here for you.

furnacefigher15

No problem

It's calls like this when I always learned the most. I hope you did the same. Next time you see it, you'll know what to do.

NYplumber

j w/ damper

Tim, we spoke about this two weeks ago when I had a damper jumper question, however I'm still confused after looking over the pdf at the wiring for the model ending in J.

How do the four wires for the dampermotor tie in?

furnacefigher15

Page 10 figure 12

http://customer.honeywell.com/techlit/pdf/60-0000s/60-2278.pdf



Power to open damper between 1 and 4 on call for heat.



End Switch closes between 2 and 3 closing the burner circuit.

Tim McElwain

The L8148E version with a vent damper is an

OEM control and is not available as a Tradeline model. That being said the L8148J Universal replacement can't replace that version of the L8148E. You have to use cross references for these controls. The "J" will however replace many high limit only relays both 24 volts and powerpile.



There is a way to wire a vent damper without the plug in on a control. You would have to cut the plug of one end (the control end not the damper end) You would if it is a Honeywell damper have to power the motor when no call for heat as it is powered closed and springs open when power is removed.The others Johnson and Field (Effikal) are power to open power to close or what is called the stalled motor principle. I do not want to get into the wiring here unless you feel I need to do that. I would rather send you a wiring diagram as it would be less confusing.

Tim McElwain

Just to clear up

What is shown on figure 12 in the L8148 spec sheet:



Terminal 1 is also the orange wire



Terminal 2 is the black wire



Terminal 3 is the blue wire



Terminal 4 is the yellow wire



That makes it easier when you are taking the harness apart to wire it with no damper plug in. The figure 12 diagram is showing the L814E which has a plug in for the damper.



The spec sheet does not show how to wire the L8148J with the vent damper so again if you e-mail me at gastc@cox.net I will send you a diagram showing how to wire it.

Alan (California Radiant) Forbes

Even though

the vent damper was working fine, I removed it from the safety train.  The spill switch and flame roll-out switch are still in line, but the vent damper is just an unreliable nuisance.



Sorry to offend anyone.

Plumdog_2

Unreliable nuisance?

They are a sort of good idea to prevent stack losses between burner cycles, but they cause a lot of grief, and the price of new replacements will make almost any customer gag and convulse. And I don't blame them. When you look at what you are getting and the huge pricetag, it doesn't seem like a good value. I mean, come on, you could buy a decent old dirtbike or something for that kind of money. Why don't those guys offer just the actuator and a universal cable set and sell it for a fair price?

Tim McElwain

Originally

vent dampers were supposed to be field repairable by just changing the actuator. That did not last very long.



One way to extend the life of the vent damper is to move it as close to the chimney or main vent as possible. Getting it away from the top of the draft hood reduces the temperature and also the wet time it is exposed to. I have found this to really make a difference.