17 second short cycle SOLVED !!!

Robert O'Connor_11

Like you say sometimes they fused the
neutral wire too.

Yikes!!!

All the best

Robert

ME

James Bates

Short Cycle MADNESS

is finally solved. Trane two pipe system (75 yrs old), Weil McLain 572 steam boiler (35 yrs old, Beckett burner (2 yrs old) when thermostat and vaporstat mercury were both engaged ON would cycle on/off every 17 seconds after 1 or 2 normal cold start up cycles. Honeywell chronotherm thermostat (T8085A) or Honeywell stack relay (RA117A) were originally suspect. Turns out it was the stack relay (only 2 years old). Cycling fine and regular now with a new stack relay installed . Purring like a kitten at 10 OZ. mains and 8 OZ. differential vaporstat settings../..Alfred/Jim..

Mad Dog_2

Nice troubleshooting guys

as you know, there is no substitute for sitting in the boiler room for.....as long as it takes...to find a problem. Mad Dog

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scott inM.E.

RA117A

If the customer still has one of these dinosaurs time for some serious updates.

clammy

agree

Please get rid of that stack relay they are still used but with a 2 year old beckett it sounds like the oil tech was to lazy to remove and replace with the cad cell relay which is alot shorter timed then a stack relay which in turn means less oil soaked boiler in a no inigition promblem .The only tech i know that would not have s##t canned tha control would be somew one to lazy to do a little re wiring and didn't really care sounds like a just gettem flame deal peace clammy

ed wallace

stack switch

now why the heck do you have a stack switch on a 2 yr old burner thats just laznest on the installers part

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Steamhead (in transit)

Easy, guys

I've run into situations where the wiring is old enough that it's best not to disturb it any more than you absolutely have to. In such cases it can be best to leave the RA117 where it is, and rewire everything when the boiler is replaced. A lot depends on the type and condition of the present boiler, and how much of the old wiring they re-used during the replacement.

With that said- from what I found on the W-M web site, the 72 series (572 = 5 section boiler of 72 series) was essentially an old all-fuel boiler design with a dry base. If this installation is really only 35 years old, it must have been one of the very last ones made. This type of boiler can be baffled to improve its efficiency, and fitted with a better burner like the Beckett, but a new one will be even more efficient.

James, it's time to start saving up. Here's what W-M offers now. This one is on a Kriebel Vapor system.

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RonWHC

Ahem.

Joe Grosso

New burner

Sorry, Steamer I don't agree. I just did 2 recently. Rip the wires off, install burner with modern control. No big deal. Bring wire thru LWCO and P-trol, on to burner. Whats the problem there? By the way Frank, Merry Christmas Buddy.

Steamhead (in transit)

Well,

if you get into the wiring, the insulation disintegrates and you end up having to replace it all like I've had to, and the customer screams at you "The wiring was fine until YOU got here and messed with it"- and tells your boss the same thing and he yells at you too- oops, I forgot I'm the co-boss now. I hate flashbacks..... anyway, there's some real old stuff in the typical Baltimore basement and not all of it got changed in the old days when a boiler was replaced, dry-fired steamers can be especially hard on wiring even if it's not directly attached to the boiler. You have to use your judgement in these cases.

Now, if I found questionable wiring in my house I'd simply replace it, whether or not it was in imminent danger of failing. But some customers don't see it that way. So sometimes it's best to leave it alone. In a perfect world, I'd pull out every stack relay I ran into.

Interestingly, some time ago this subject came up and none other than Firedragon posted to the effect that if something is in place and working and it looks like messing with it will cause problems, one should leave it alone. I'll post a link to that thread if I can find it.......

On the other hand, if the wiring was OK in James' case it might have been laziness, or it might have been he was doing what the boss told him to. But I can't say since I haven't actually seen it.

Happy Holidays, all.

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Robert O'Connor_8

Well

In this case the Ra 117 could be left in place and used as a junction box. Then the cad cell control could be mounted on the burner.

I would rather see the wiring up to snuff but you'd still be gaining getting rid of the stack control.

I am not a fan of stack switches. I have had to clean up some real messes

All the best

Robert

ME

adayton_2

OLD Steamhead, Ah, Er.... I mean...

old wire.. lol. In fact this house including the boiler area is riddled with almost exclusively CLOTH wire (i.e., REAL OLD..) Even though the Electric mains was updated to new 200 Amp circuit breaker panel the boiler "safety switch" is a two pole knife switch complete with a fuse in each leg (neutral and hot). Thermostat wire is cloth, and aquastat wire is cloth, both going into the stack relay. All other wiring on the "new" (35 to 40 year old) Weil McLain 572 boiler is BX (armour cable)The new (Two year old) Beckett was simply "plug replaced" into the existing setup.. That said, I suppose two years ago the installer could have installed optical flame safety sensor at that time. About the same time frame (two years ago) the stack relay was also replaced. alfred/Jim

Steamhead (in transit)

There's something I really hate

those old fused knife switches.

When oil burners were first being installed, many existing electric service equipment was already maxed out. Many original services were only 30 amps! That 200 amp panel was unheard of in residential use back then.

So the Dead Men used fused switches to get around this. Apparently it was OK to the AHJs back then to locate these fused switches in the stairway, or the outside basement entrance, rather than next to the original fuse panel. So they did. It wasn't out of character at that time, we've all seen those original electrical installations that had little fuse boxes all over the basement. It was also normal to fuse the neutral as well as the hot back then- the earliest systems did not have any kind of polarity at all, according to an electrician I knew long ago who is now a Dead Man.

I try to replace these switches when I find them- since the overcurrent (breaker) for the burner circuit is now in the main panel, the fuses are no longer needed, and the easily accessible live parts inside these units could electrocute someone. And sometimes the old fuses come loose, or the knife blades get corroded, or something similar will happen and cause a no-heat call. Recently I found out- the hard way- that the polarity had gotten reversed when an old fused switch was originally installed.

But I don't get to replace them all...........



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Bob W._3

The switch I just cut out of my old boiler was a fused switch. Both the hot and ground (neutral) were fused. The box was manufactured by the Colt Pat. Fire Arms Co. Didn't know they made electrical equipment. Its the only Colt I own:)

Constantin

Ditto...

... we had a knife switch on our Williamson 200kBTU/hr oil furnace. It's not the fuses that gave me the willies about the thing, it was the open access to the high voltage inside the box.

When the time came to make the changes to more modern wiring practices, perhaps the Dead Men laughed at the need of insulating knife switches and the like the same way we laugh at flammable-vapor-resistant water heaters?

adayton_2

Knife Switch is located

in basement stairwell, suprise...suprise..lol :-).
Jim and I would like to thank all the denisens of the wall for all the sage words of advice you all have shared over the last couple of months during our search and repair mission. Jim's vintage Trane Vapor system with Weil McLane Steam boiler is worthy and deserving of respect and attention to proper maintenance details. We feel that it will last another 75 years. ( and Jim assures me he will try mightily to stick around that long.....lol). Happy Hollidays to all from Jim and Alfred