Spill switch still tripping after replacement

frankiemaratta

Hello guys new to the forum. I have a slantfin natural gas boiler (steam) in one of my properties. Boiler worked fine a few months ago, but we just tried firing it for the first time since then and it does not fire. When we hit the reset button on the spill switch it fires and then it shuts off within 5-10 minutes. My plumber helped out and picked up a new spill switch. Part number 412057100. However, no change, it’s still doing the same thing. When we put a jumper cable on it to bypass the switch, it runs perfectly. We are totally stumped and have been trying to figure this out for weeks now. If you guys need the model boiler I will certainly get that for you next time I am at this property. It is not that old, I would say 2-3 years old max.

Thanks
Frank

nicholas bonham-carter

Have you checked the flue, and the fireside of the boiler, for an obstruction, because it seems the spill switch is doing its job.
Is there a CO detector on site?—NBC

STEAM DOCTOR

Blocked chimney. Don't jump out spill switch before making appointment with mortician

frankiemaratta

No blockages in chimney or flue

pecmsg

Never bypass a SAFETY Switch.

Find a technician that knows what there doing, they'll need a combustion analyzer!

ratio

I don't have much experience with spill switches specifically, but it's a device that is intended to keep the boiler from killing you. I'd expect it to be of at least respectable reliability—meaning that it's doing its job of trying to keep you alive.

It's time to look at other changes that could have effected the venting. New dryer? Range vent? Did you start using a whole-house fan, or even a box fan in a window? Did you do any caulking or sealing to stop infiltration?

What's changed in the time since it worked fine?

Jamie Hall

What @ratio said. Assuming that you are absolutely sure that the chimney isn't blocked, even partially.

ChrisJ

The spill switch is a simple bimetal switch that trips if it gets too hot.

I assume this is mounted to your drafthood? Why is the drafthood getting so hot?

For some reason the heat isn't able to leave up the chimney. Someone needs to figure out why before people die.

Is there a negative pressure in the room because of an exhaust fan? Can enough fresh air get in? If you open a window do you feel a strong breeze being pulled in?

JohnNY

frankiemaratta said:

When we put a jumper cable on it to bypass the switch, it runs perfectly.

A tripped spill switch is an effect, not a cause.
My company has a standing order that leaving a safety device of any kind in a jumpered condition, under my license, is grounds for dismissal. Let my competitors appear in criminal court for negligence. It's not going to be me.

Tell your plumber to either figure out why the flue isn't drafting or call someone immediately who can assess and correct the issue.

JohnNY

pecmsg said:

Never bypass a SAFETY Switch.

they'll need a combustion analyzer!

No they don't. They need to look around and figure out how combustion air will get in, mix with fuel, burn, and get out.

Alan (California Radiant) Forbes

Spill switch or flame rollout switch?

If it's on the draft diverter, it's a spill switch. If it's in front of the burner, it's a flame rollout switch.

Jamie Hall

Alan (California Radiant) Forbes said:

Spill switch or flame rollout switch?

If it's on the draft diverter, it's a spill switch. If it's in front of the burner, it's a flame rollout switch.

Either way it's a required safety... bypassing it is just plain dumb. Sorry. Find out why it's tripping and fix it.

ChrisJ

Jamie Hall said:

Alan (California Radiant) Forbes said:

Spill switch or flame rollout switch?

If it's on the draft diverter, it's a spill switch. If it's in front of the burner, it's a flame rollout switch.

Either way it's a required safety... bypassing it is just plain dumb. Sorry. Find out why it's tripping and fix it.

I think the difference is draft issues seem very common but to trip a roll out switch you've got something really ugly going on.

Keith M

Frank, it appears the spill switch is doing it's job. I suggest your contractor or you call Slant/Fin technical service department and discuss the situation. Also have the actual boiler model number and serial number. Please note we have two different spill switch temperatures for Galaxy steam boilers. The most used one is higher than the temperature setting than the part number you listed. Take note or ANY changes in the building or boiler room area. Any new water heaters, boiler room doors, exhaust fans, any new clothes dryers...etc? Was any work performed on the roof? or chimney? Pictures of the boiler installation and room are also helpful.
Slant/Fin technical services may be reached at 516 484 2600 from 9am to 5pm Monday thru Friday. If I am in the office I try to answer technical services calls until 7pm. We WANT YOU to call us when you have issues, better safe than sorry. As other people stated, spill switches are safety devices! Do not by-pass them.
Keith Muhlmeister
Slant/Fin Corporation

gennady

Open all the doors between boiler room and outdoors and fire boiler. If boiler runs well then the problem either with blocked fresh air intake or you have an exhaust fan somewhere creating negative pressure in boiler room area.

HVACNUT

You stated no blockages in the chimney or flue. Was it eyeballed, or a certified chimney company checked it?
Is there a stainless steel liner?
Nothing changed to affect the pressure differential in the space? Insulation, basement door weather stripping, etc? When "The boiler worked fine a few months ago", the flue temp could have been on the cusp of tripping the spill switch. Something put it over the edge. It's not a good situation and it should be top priority to fix it and have a combustion analysis done by a pro. Maybe one of the steam guys here are near you and can go over the whole system for you. I'm sure its due.

ChrisJ

Something did change.

The temperature outside.

Alan (California Radiant) Forbes

Did you have some roof work done? Maybe the flue termination piece was pushed too far down or they didn't use the proper one.
Or perhaps the chimney just doesn't draw well. I remember a 4-story Metalbestos flue that had no draw. We had to replace all the boiler's burners because they were all toast.

Lance

I have seen this before. But there can be many causes of which many are stated before me. Venting of flue, is all about air pressure and buoyancy.
Is there a leak in the boiler that allows steam to increase volume to the chimney and it spills? Is there a combustion leak between the seals of the sections. They use caulk not rope these days and if overheated will degrade and leak.
Is the burner overfired? Too much gas pressure? Defective valve?
Does the flue take too long to establish a draft = to -.04 in. Wc.? Could the chimney be leaking? need a liner? Is this a windy incident event? The combustion analysis meter is a wonderful required tool to use. If I want to know the weather, I stick my head outside, if I want to know the temperature, I get a thermometer.