Laars

Bill Clinton_5

Hey, Allen! Haven't seen you in an age. If you're measuring 14 volts across the relay, I think that has to mean there is a load in series in that circuit. Two loads split the available voltage drop between them. Try lookin close at the wiring of the zone valve: My best guess is that the heater coil is drawing off some of that voltage drop, although I have to admit I can't quite picture it. The heater coil is wired between terminals 1 and 2 on that z-valve. When operating there should be a 24 volt drop across those terminals: Measure it and if its something lower, you've found your culprit. Terminal two is shared between the heater coil circuit and the end switch circuit. Terminal 3 should be the other lead to the end switch ane should not be shared.

Somewhere in these circuits there is a load that ought not be there. A voltage drop across it will identify it.

Bill Clinton

Alan(OnVacationInOregon)Forbes

Laars

This boiler is in San Francisco, 15-20 year old JVS-50 CH with a power vent. The owner complained about a loud clicking noise and I replaced the inducer relay which didn't help. I measured the voltage from the on-board transformer and it held steady at 24-25 volts, but when I measured it at the relay, it was typically around 14 volts which brought on the fluttering relay. After a few seconds, the voltage came up to 24 volts and the relay was fine.

The transformer is also being used to power 2 B&G zone valves, but it's been fine for years. The wiring diagram shows one transformer leg going through an in-line fuse and then to the relay. The other leg goes through the thermostats and to the relay. I can't figure out where the voltage drop occurs.

Joan at Laars, can you help? Anyone else?

Brendan_4

fluttering relay

Alan. I too experienced the same fluttering in a Laars JVS 75 turned out to be the thermistor installed in the ci wall a temporary shunt should eliminate the flutter
Brendan

Unknown

Flowguard board

Does that boiler have the little circuit board on it? That control (that we did away with) can be the cause. Let me find the drawing that shows how to "upgrade" the boiler to do away with the board.

Jumper between TP1 and TP3 on the board to bypass the board; leave the board in place. Make sure that with any single zone operating, that the temperature rise is 20°F, or less.

That's it!

Noel

Joannie_15

Hi Alan

Hi, Alan.

Noel is getting you information on the Flo Guard (thermistor and circuit board) that we used in the 1987-1989 time frame, since that was brought up as a possible cause. That normally caused the unit to simply stop firing, but you never know. If that doesn't help you out, give us a call at 603-335-6300. The serial number of the unit will help, if you have it.

Is there a vent damper on this? You said that after a few seconds, the voltage came up, and it made me wonder if that few seconds is the time it takes to open the vent damper.

Let us know.

Joannie

Alan(OnVacationInOregon)Forbes

Laars

Thanks, everyone.

Joannie: the serial number is 1916382 and I don't remember seeing a circuit board. No vent daamper since it's power vented.

Joannie_15

Serial Number

Yeah, that unit was built in 1991, after the Flo Guard was already gone. Have you heard the noise the homeowner's talking about? There's not much in those JV units. They're pretty basic.

You might want to give Noel a call here at 603-335-6300 and have a meeting of the minds. We're here from 8:00AM to 5:00PM eastern.

hot_rod

The heat pill type B&G ZV's?

those small red box type? Sounds like an end switch taking a while to make good contact and fire the boiler. i've seen those ZV's get weak after time. They work enough to open flow but not make a solid end switch connection. I think you can get to the contact points to spray or clean. Or replace the heads.

hot rod

Alan(OnVacationInOregon)Forbes

B & G

Those are the ones. Thanks, HR.....I'll check them out. Seems like that could very well be the problem although the problem occurs even when both zone valves are open which would mean that they both have the same issue.

Alan(OnVacationInOregon)Forbes

Coil

Hi, Bill. While the zone valves are opening, the voltage measured at the transformer did not drop; I didn't measure it at the relay, but I presume it's the same. The voltage drop only happens when one of the end switches close. As yet, I don't know if it only starts to chatter with one particular zone valve.

BTW, this is one of your jobs........on Broadway.

Bill Clinton_5

that explains it

You don't need a technician: You need an exorcist.

One clue: You say the voltage doesn't drop until the end switch closes: How is there 24 volts across the relay when the end switch is open? The circuit is open til the end switch closes, no?

Good to hear from you.

Bill

Bill Clinton_5

Still thinking: That installation is so far back I can't remember much about it, so I got my local hypnotist to lead me through a past life regression that yielded a few vague memories.

I used to use a lot of Laars boilers. Did until they made them so efficient (improved, I believe is the word) that condensation on their nice finned copper tube hx became a killer of a problem. Stopped.

anyway, I used to steal 14 volts from the onboard transformer to operate a couple of zone valves as in this installation. Two was about the max. My vague recollection is that for a couple of installation I used the bottom of the three terminals as one leg for the 24 volts. (There are three screw terminals: The top two connected together through external controls trip the relay) If you put the volt meter between top and bottom terminals, you would get 24 volts: Looked like this was a hot leg to the transformer, so I tried wiring from the top terminal to my t'stat, to my zone valve, thence back to the bottom terminal. Zone valve end switch connected top to middle terminals. Worked great..for a while..until relay started chattering, low voltage reading across relaly. Gradually I worked out this didn't work so good, so I changed the wiring and made my connection to the transformer internally--teed into other leg of transformer.

Could this be the scenario here? Waited 17 years to bite?

If that isn't it, i have a supply of Black Copal given me by a Mayan Shaman in Belize: Its used to drive away evil spirits. You burn it like incense. I could give you some. I don't leave home without it.

Bill

JBW_2

Broadway

Broadway in Oakland?
Used to live on thirtieth and Richmond right on the other side of that little Creek. Love that area...
Have you guys installed the Rheos yet??

Josh W

tim smith

B&G zone valves

Yeah, I am betting on one of the B&G operators. Does it only happen when one or the other zone valves turn on or when either one does. Also could be wearing heat motors on those B&Gs w/ the cumulative amp draw exceeding the VA of the transformer. .02 worth