no heatdear nestor,thank you for the reply. it was helpful

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  #1  
Old 10-02-00, 08:22 PM
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dear nestor, thank you for the reply. it was helpful. i'll try to explain the system a little bit better. there are 2 circulationpumps. there is one relay mounted behind the accesspanel of the gas furnace
(HONEYWELL L8148J). i could not find any zonevalves anywhere.i found 3 ventvalves (no air in the system).closing (jumperwire) the upper floor thermostat will not activate the upper floor circulationpump nor the burner. downstairs (lower level) works properly. i am pretty sure that the c-pumps are thermostat activated. (do not run continously).i'll give myself another couple of days before i call a technician.would be nice if it was a stuck zonevalve but for the world of it, i just can't find one.
 
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  #2  
Old 10-02-00, 09:33 PM
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I. Mitchel:

If you have two thermostats and two zone circulating pumps, then you won't have any zone valves.

You see, the way it works is that the thermostat is 24 volts and when it closes calling for heat it can either complete a 24 volt circuit to a zone valve or complete a 24 volt circuit to a relay.
If it completes a 24 volt circuit to a zone valve, the valve opens allowing water to flow through the radiators of that zone. (Normally, with zone valves there's one circulating pump for the whole building running continuously, so when the valve opens water flows through the radiators without another circuit to turn on a pump.)
If it completes a 24 volt circuit to a relay, then the electromagnet in the relay is energized and that snaps a pair of 120V contacts closed and that closes a 120V circuit to a circulating pump. In that case, there's a thermostat on the boiler that's connected to the gas valve to keep the boiler water warm all the time, just like on a hot water heater. When the thermostat closes, the relay closes, the pump starts turning and the hot water starts flowing through the radiators of that zone.

Have someone turn that upstairs thermostat back and forth upstairs while you listen beside the boiler to hear the clicking of a relay. If you don't hear any relay click on, then it's possible that the boiler doesn't have a second relay for a second circulating pump, and the second circulating pump isn't even connected to a relay.

I tried to locate your previous post but couldn't. If this is a system that's already been in operation and is simply not working now on the upper floor for some reason, we can rule out a lot of possibilities. However, if it's just been installed, then it's very possible that the plumber simply left the wires to the circulating pump unconnected because the boiler didn't have provision for another circulating pump, and he realized that normally an electrician would then be called in to install a second relay for the new pump (and possibly a second 40VA transformer) to drive the new thermostat and electromagnet in the relay.
 
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Old 10-03-00, 07:16 AM
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dear nestor,there is no clicking of the relay when operating the upper level thermostat.the system was installed in 1972.a gasvalve was changed in 1998.other than that it worked fine ever since.was i right in identifying the HONEYWELL L8148J as THE RELAY, because i have 2 additional boxes (3x3x4 inches) mounted on the side of the furnace with all kinds of connections (between each other-from the thermostats- to the circulationpumps-to the L8148J).these 2 boxes are identified as ITT GENERAL CONTROLS CAT.N0 R4F021D ,volts 24V, relay-two pole-double throw).the pumps are TACO 007-1 1/25hp
115V- 60 HZ- 3250RPM.THANK YOU FOR YOUR INTERST.IM
 
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Old 10-03-00, 04:03 PM
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Hi:

The 2 relays you refer to are most likely the relays that operate the zone pumps. If you have someone turn the downstairs t-stat on/off while you monitor the relays, you'll probably hear one of them pull in as well as the aquastat.[the H/W L8148J] Since you jumped out the upstirs t-stat [did you actually take the stat off the wall and jump the wires?], the problem is either the wiring from upstairs back to boiler or the relay itself. If you're familiar with wiring diagrams, go to http://hbctechlit.honeywell.com/ where you'll be able to search for and download a 12 page document that explains the L8148J and how to wire it. It's in pdf format so you'll need Adobe Acrobat Reader which you can get for free from Adobe. Thanks. John.
 
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Old 10-03-00, 06:19 PM
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bigjohn,working the downstairs thermostat i can in fact hear one of the 'zonepump relays' as well as the aquastat 'pull in' .(to use your term).as for jumping the upstairs thermostat,i did remove it from the wall and jumped the wires themselves. your assessment of the problem being "in the wiring or the relay itself" - are you referring to one of the zonevalve relays or the H/W L8148J ?i did download the wiring diagram of the aquastat a few days ago (looks pretty intimidating).as for it being the relay (more likely),would you recommend replacment or repairing? thank you IM
 
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Old 10-03-00, 06:33 PM
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bigjohn, working the downstairs thermostat i can in fact hear one of the zonepump relays and the aquastat 'pull in'. the upstairs thermostat i did remove from the wall and jumped the wires themselves. as for the problem being in the wiring or the relay itself, are you referring to the zonevalve relay or the aquastat?? i did download the L8148J wiringdiagram a few days ago (looks intimidating)- took off the cover of the L8148J and tried to match up everything with the schematics. visually it looks ok (no off wires or anything). provided, it's a bad relay, do you recommend repair or replacement? are there any other tests i can perform? thank you. IM
 
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Old 10-03-00, 09:21 PM
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imitchel:

I went to the Honeywell website and typed in L8148J in their search engine and it came back saying 0 documents found. What am I doing wrong?

These things are not that complicated. If you have an upstairs thermostat and a circulating pump for the upstairs, then that thermostat, the transformer for it and the relay in the boiler are all wired in series and represent a 24 volt circuit. When that circuit is completed, the 24 volt relay closes a pair of 120 V contacts which turns on the circulating pump.

I would check to see if there's 24 volts at the upstair thermostat. If you can make and break continuity across the thermostat by turning it up or down, but there's no voltage across it, then I would use a long wire and try to find continuity between one of the wires at the thermostat and one of the 24V transformers. When you find the transformer that thermostat is connected to, check to see if there's 24 volts across it.

The first thing to do is to identify where each of these components in the upstairs 24 volt circuit is, then test with a multimeter to see where the bust is.
 
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Old 10-04-00, 04:36 AM
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Hi Guys:

I mean one of the zone pump relays. We know the H/W L8148J is ok because it works with the downstairs thermostat. You have 2 relays at the boiler. By operating the downstairs t-stat, you can tell which is for upstairs and which is for downstairs. You either don't have power for the upstaits relay, the relay is bad or the interconecting wiring has a problem. Study the wiring diagram on page 11 of the H/W booklet. I'll bet your system is wired just like it or very similar. You are at a point where you either need to understand the wiring & start troubleshooting with a multimeter or you'll have to call a service tech. Sometimes the Honeywell website acts up. Try typing in L8 and search through the results. Thanks. John.
 
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Old 10-05-00, 12:04 AM
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I found the schematic for the L8148J.

The way to interpret the wiring diagram on page 10 is that when the thermostat closes, it completes the circuite between terminals T and TV, closing the circuit on the low voltage side of the transformer. The resistance between terminals T and W is the coil of the relay itself, so when there's 24 volts flowing through that loop, then contacts 1K1, 1K2 and 1K3 simultaneously close. 1K1 closes the 120V circuit to the circulating pump so the water starts moving. 1K3 closes so that IF there's a 24V gas valve connected between B1 and B3 that gas valve will open and the boiler fire up PROVIDED the high limit switch between terminals B and R allows it. On a gas valve powered by a thermopile, the voltage generated by the thermopile is applied at terminals B1 and B2. That is, if you connect B1 and B2, voltage from the thermopile flows through the gas valve and the gas valve opens. This is done with contact 1K2 which has a manual override switch. Thus, if the thermostat closes calling for heat, contact 1K2 closes, and the o.9 volts generated by the thermopile flows through that loop and completes the circuit through the gas valve, so the boiler fires up. This circuit is also controlled by the high limit, but you can override the thermostat and turn the boiler on manually just by flipping the auto/manual switch.

I'm convinced that this L8148J control wasn't suitable once a second circulating pump was added because only the original thermostat would turn on the gas valve. So, the L8148J was retained only because it provided both a high limit and a manual override switch for the boiler, and two additional 24 volt relays were installed.

I expect that if you draw out the new wiring diagram, the existing L8148J is used only as a high limit and a manual override on the boiler, and the two ITT relays mentioned are the relays controlling the circulating pumps.
 
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Old 10-05-00, 12:28 AM
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imitchel:

Let me rephrase my last paragraph.

The original L8148J was unsuitable once a second circulating pump was added because the L8148J only turned on the gas valve when the you connected terminals T and TV, and then it only turned on one circulating pump.

If the L8148J was used, then the gas valve would only go on when the L8148 allowed it to, and the L8148J could only be controlled by one thermostat. If you connected both thermostats and both circulating pumps to it, then both pumps would come on when either thermostat closed. If you used the L8148J for only one thermostat and one circulating pump, then the other thermostat wouldn't make the gas valve come on, so you got cold water flowing through the radiators. The owner realized that the only way he could make it work was to use the L8148J as a high limit, and install separate relays for each circulating pump and each relay being controlled by it's own thermostat. It is those two ITT boxes mentioned that were added to do this, and the wiring between them is simply to provide 24 volt power to each of those relays from the L8148J.

I expect that right now, the power to both relays is taken off terminals Z and TV, and the auto/manual switch is now being used to turn the furnace on at the beginning of each heating season and off at the end of each heating season. During the heating season, the temperature of the water is controlled by the high limit as it's the only control on the gas valve now. Each thermostat and relay is connected in series between terminals Z and TV on the L8148J, so that when either thermostat closes, then it's respective relay closes, completing the 120V circuit to one circulating pump.
 
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Old 10-05-00, 12:44 AM
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imitchel:

Those curved lines between the terminals marked TP, Z and W on the L8148J are just jumpers. The numbered triangles on the schematic are basically the same as numbered footnotes in a document. Note 3 says that jumper Z to TP is to be removed if you have a thermopile driven gas valve, so that there's no electrical connection between the 24 volts between terminals Z and TV and the 0.9 volt circuit between the terminals B1 and B2.

Hope this helps you finally make sense of it all.
 
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Old 10-05-00, 04:25 AM
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Hi Nestor:

I think that the L8148J came installed on the boiler from the manufacturer and the pump relays were either added by the installer or were accessories from the manufacturer. [of the boiler] Take another look at the wiring for the J model and you'll see that it can be used with a 24 volt gas valve or a millivolt gas valve. The auto/manual switch will only work with the millivolt gas valve. That's why they have 3 terminals marked B. [for burner] Isn't the Honeywell website great? I use it all the time. Thanks. John.
 
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Old 10-05-00, 09:31 PM
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Bigjohn:
I'm ALMOST POSITIVE that the L8148J came installed on the boiler from the manufacturer and the pump relays were added when it was decided to break the heating system into two zones and add a second circulating pump. This control is CLEARLY meant for a single zone system, and no knowledgeable contractor would have installed it on a two zone system.

What has happened here is that someone has decided to convert to a two zone system, and has tried to salvage whatever functions he could from the L8148J. So now, it acts as nothing more than a source of 24V power, an on/off switch and a thermostat to control the boiler water temperature. It's design as a boiler control is simply not adaptable to a two zone system.

I hadn't noticed that it was designed to operate with both 24V and pilot light powered gas valves. (smirk)
 
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Old 10-05-00, 10:26 PM
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I. Mitchell:

Are you still alive? Did you read my responses? Does that schematic make sense now? Do I win a prize for figuring it out?
 
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Old 10-05-00, 11:40 PM
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NESTOR,BIGJOHN, YES,I AM STILL ALIVE. CONGRATULATIONS FOR FIGURING IT OUT.I AM MORE CONFUSED THAN EVER. WHAT EXACTLY DOES IT MEAN TO MY SITUATION? NESTOR, AS FOR THE PRIZE- YOU WIN THE FIRST PRIZE OF COURSE. I HAVE A PROFESSIONAL COMING TOMORROW (THIS MORNING)
TO HAVE A LOOK AND HOPEFULLY FIX IT.TO THE BEST OF MY KNOWLEDGE THE WHOLE SYSTEM WAS INSTALLED 'AS IS' IN 1972. NO CHANGES TO THE SYSTEM WERE MADE SINCE.(BUT THE CHANGE OF THE GASVALVE IN '98).MY CONFIDENCE LEVEL IS NOT HIGH ENOUGH TO DO ANYTHING ELSE WITH IT MYSELF.(ALL THESE DIFFERNET CICUITS RIGHT NEXT TO THE PILOT - YOU KNOW WHAT I MEAN)DON'T EVEN HAVE A MULTIMETER IN THE HOUSE. YOU GUYS ARE GOOD AND I THANK YOU VERY MUCH. WILL LET YOU KNOW HOW I MADE OUT.IM
 
  #16  
Old 10-06-00, 12:00 AM
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THE INITIAL DESIGN WAS FOR A ONE ZONE ONLY -
BUT I INSISTED ON A 2 ZONE (AFTER TALKING TO SOME PEOPLE) AND THAT'S IN FACT WHAT I ENDED UP WITH.THIS DECISION HOWEVER WAS MADE BEFORE THE ACTUAL INSTALLATION WAS MADE AT THE TIME THE HOUSE WAS BUILT.
 
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Old 10-06-00, 10:41 PM
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I Mitchel:

The schematic is not at all difficult. I expect that if you read through my last posts with a diagram nearby for reference, you would understand it much better than you did upon first seeing it.

The boiler control you ended up with is one that's suitable only for a single zone system and pretty well unadaptable to a two zone system. I would contact Honeywell to get their opinion. You're using it, and it's performing some functions, but it's not a well designed system the way it stands now. However, you must understand that I make that statement without having seen the way it was modified for two zone operation. Perhaps the contractor did things that haven't occured to me, and it may be that I'm mistaken when I contend the control is inappropriate.

Anyhow, all's well that ends well.
 
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