Why does the boiler need a thermostat relay?

NYCDave

We recently had a new steam boiler installed, Burnham IN8. We had various problems with the control switches, and one of the thing I noticed is that the plumbers did not install the Thermostat relay switch, and instead put the Thermostat switch itself directly into the control circuit, between the igniter circuit and the ground. So when the thermostat is open, the burner isn't connected to ground, and when the thermostat closes to call for heat, the burner is connected. In the manual, it says the thermostat should control a relay, and the relay switch should control the burner. In that circuit the relay switch is also upstream of the burner (between the burner and the 24V connection). Anybody out there know why the relay is used, and whether it's a problem not to have it?

Thanks!

Jamie Hall

Argh. Well, first off you never, ever put a switch or disconnect into a ground or neutral wire. Ever. For any reason. So the wiring you describe is wrong from the get go.

Second, a thermostat can either control a relay or the burner control system; the latter is more common on oil. The idea of the relay is to remove the current load of the ignitor, in your case, from the thermostat -- which shouldn't be switching more and a few tenths of an ampere at 24 vac at most (unless, of course, it is a line voltage power thermostat, which is a completely different critter).

Have him come back and connect it correctly.

nicholas bonham-carter

I wonder what other things in the installation he may have done differently from the manual.
Take some pictures of the installation, and post them here, as the piping requirements are very important.—NBC

NYCDave

Thanks Jamie!

Isolating the thermostat from the igniter current makes a lot of sense! Any ideas about what that current typically is? The thermostat wires are very thin, would hate to have them fry somewhere in the middle of the wall…

As for the switch being downstream of the load, I know that is bad practice... In fact we had a problem where the VXT automated water feeder was somehow causing a short, bypassing the thermostat, and the boiler wouldn’t turn off except by cutting the power manually... still trying to figure out why a new auto feeder would cause such a problem after only a few weeks… Anyone have any ideas on that?

Jamie Hall

Dunno about the auto feeder -- but from the sound of it, whoever is doing your control wiring is being a bit creative -- which is fine if they know exactly what they are doing and why, and documents everything, but otherwise... not so much.

EBEBRATT-Ed

Post some pictures of the boiler and controls. We would love to see it. Take a bunch and someone can help you out. Without seeing it were just guessing..........just like the plumber did by the sound of it

NYCDave

Haven't had a chance to get the plumber back in to install the missing thermostat relay or move the switches upstream of the burner, but in the meanwhile, the LWCO switch has stopped working... I had taken removed the auto feeder because it was causing a short in the circuit somehow, so I was following the water level closely.. we are losing about an inch per day on the sight glass (anybody know what volume that corresponds to for an IN8 boiler???) and today it dropped below the level of the probe, but the burner kept going... I added more water for now, but am thinking I may need to replace the probe. I think I just screw it out and screw a new on in right? Can I use teflon tape, or do I need pipe dope, or something else? Thanks!!!

Jamie Hall

Good grief. If the LWCO didn't shut off the boiler when the water level dropped below the probe, please, please do yourself and your family a favour and stop playing around. Shut the thing off with the master power switch. Use space heaters if needed to keep the place above freezing. And find someone who knows what they are doing to fix the thing.

JUGHNE

No Teflon at all on the probe. Teflon has insulating properties and the probe relies upon those threads having a good ground to the boiler.

How old is this installation, the LWCO probably came with the boiler.

1" a day?? Maybe an inch during operation but all water should come back eventually. You must have a leak that needs to be corrected. Any return pipes under the floor?? Steam leaking from vents?

Plumber may realize he was in over his head.
Pictures please.

NYCDave

Thanks Jughne!! This is a new installation as of November. The old boiler (oil fired) developed holes in the top of two sections... There must be a leak somewhere, I agree, but haven't had any luck finding anything. Return lines are above ground, but have been walled in behind drywall... still would expect to see a wet spot if this much was leaking as water... we do have one radiator valve (not vent) that leaks steam continuously, but could that account for an inch per day (I'm assuming that's about a gallon of water or so)?

Regarding replacing the probe, if not teflon tape, do you use pipe dope then, or nothing? would really appreciate an answer to that question...

Jamie, the only 'professional' we have to work on this is the plumber who installed this, and he clearly is not very good... set the control circuit up all wrong. So, it seems I'll have to do it myself if it's going to get done right, so appreciate all the help! It's not a complicated circuit, and for now, I am monitoring the water level every morning/evening until the LWCO comes back on line... we lose about an inch/per day, but that's not so bad that the boiler will run dry...

Thanks!

KC_Jones

Dare I ask what the piping on the boiler looks like if he knows so little?

Jamie Hall

KC_Jones said:

Dare I ask what the piping on the boiler looks like if he knows so little?

Don't.

@NYCDave -- from the look of your handle, are you in the New York City area somewhere? If so, there are at least three folks I can think of at the moment who can get all this straightened out in a jiffy: @Dave0176 , @EzzyT , @JohnNY . Click on any of the names to see their profile and telephone numbers.

We'll be glad to help you as much as we can -- but there is a real limit to what can be done over the 'net that's safe!

JohnNY

Where are you in NYC? I've got guys in Manhattan and Brooklyn daily. Less often in the Queens and The Bronx.

NYCDave

Thanks Jamie, We're in Pelham, NY, that's in Westchester County, just north of the Bronx... I've asked the plumber to come back, change the LWCO probe, and rewire the control circuit as in the manual (including the relay...)... I'm not expecting much, so may reach out to one of the people you mentioned if they are willing to come up to Pelham. JohnNY do you get this far north?

Thanks again!

EzzyT

@NYCDave I do work in Westchester all time, I’ll be up in your area tomorrow afternoon. Private message me and maybe I’ll be able to stop by and take a look

JUGHNE

The LWCO probe probably is not the problem with that control.
The 1" loss per day may have been the problem that put the holes in the old boiler. Did it lose that much water per day?
Hope you have one of the pro's on the way.

Does that mean we will miss out on pictures of the new
install?