burner kicks on with thermostat off.

nicksxvs

nick here, i do home repair. i'm trying to get a steam boiler up and running its been shut down awhile. it has 4 zones and 5 thermostats but i think only two are connected. each thermo controls 2 zones. it's a weil mclein in a church. it has a separate return tank with two pumps. when i power it on with the thermostats off, the burner lights and the pressure builds to 6 lbs and the burner shuts off. an old 8 inch valve is leaking thru the packing on the shaft. there is another 4 inch valve on one of the zones that was leaking pretty bad thru the packing. i replaced that valve today and then noticed the new leak. so when the pressure drops to 2 pounds the burner comes on again. Why does this happen?

EBEBRATT-Ed

Sounds like the valves are not opening. It was common in the old churches that when $$$ get tight they install zone valve so the can try and heat only parts of a building.

Sometimes adding zone valves just screws the system up.

Either way if the boiler builds pressure quickly like that it sounds like some or all of the the zone valves are not opening. Check the piping well downstream of the zone valves to see if the piping is cold or hot.

Most likely the zone valve could be stuck or don't have power, bad thermostat, loose wires, transformer not powered could be anything

Usually the thermostat opens th e zone valve and an end switch on the zone valve closes when the valve gets open to start the boiler

nicksxvs

there are four new zone valves in now. they open when i turn the thermostats on, the problem is when i turn the thermostats off the boiler continues to cycle on and off. i started the system yesterday and the building got to warm so i turned the thermostats off but the boiler kept cycling until i flipped the power switch on the side.

Jamie Hall

You may have gotten the zone valves, but...

What is controlling the boiler itself? You clearly haven't traced that out.

First, as @EBEBRATT-Ed has said, zone valves on steam systems are often problematic. Very often. Steam boilers tend to get unhappy if they are oversized; if they are really oversized -- such as what happens when the zone valves are closed, they get very unhappy. Then there are some interesting complications around condensate return...

But, leaving all that aside, you need to find out where the burner is getting its signal to run. This is a wiring problem, not a piping problem. Again, as @EBEBRATT-Ed said, it should be getting the signal from the zone valves with the end switches wired in parallel. Apparently, not happening.

Get out your wire tracing hat, and find out where and how the boiler gets its signal.

While you are at it, take a look at the pressure control. Even for a very large building, 6 psi is way too high unless there are certain types of steam fired air handlers.

nicksxvs

thank you for the info. i was reading today the pressure should be less than a pound.. the valves and wiring are12 feet up. i don't know how a steam system operates, especially one this big.something is calling for heat but what is shutting it down. is the 6lbs a limit, should it be 1/2 lb. is 6 lbs causing the packing to leak.

mattmia2

Is there DHW or hot water heat piped off of the water in the boiler or a tankless coil in the boiler?

nicksxvs

mattmia2 said:

Is there DHW or hot water heat piped off of the water in the boiler or a tankless coil in the boiler?

no, there's separate hot water tanks. when i first started up this unit. there was no power and i found a short in the junction box powering the unit. the neutral wires about 6 of them either melted the wire nut and contacted the back of the transformer or had a direct short. i re did the connection and flipped the side switch and the unit started.

nicksxvs

i'll check the end valve switches today

HVACNUT

No manual reset high limit pressuretrol? 
Check for a clogged pigtail(s) or faulty operating pressuretrol. You'll still need to trace why the burner cycles without a heat demand.

nicksxvs

there are two devices with pigtails, i can clean the tubing but i dont know how to chech what there set at. or what the setting should be...thanks.

Jamie Hall

Somehow I have a horrible feeling that you are in way over your head, @nicksxvs . You clearly have a fairly large steam system here. You also have a fairly complex control system, which may or may not be working properly. You mention a short in a junction box which melted the neutral wires -- which you "fixed", but I don't see where you found out why the wires melted without blowing a fuse or circuit breaker. You don't know what's controlling the boiler or whether it's working (it isn't, if the boiler gets to 6 psi).

Please. Where are you located? Let us help you find someone who can help you with this system, at least to get you started.

JUGHNE

You probably have a "hot" boiler that maintains pressure constantly.
I had this in an old school.
Held 5-7 PSI all winter long, zone valves open to deliver heat.

I rewired controls so that when zone valve called then boiler would fire. Had to add relays as there were no end switches in valves.
Also replaced all control wiring and connections.
Once you change some control wires you are responsible for all of them.

As Jamie said you may be in over your head, you need someone who understands all the safety controls and proper sequence of operation.

I asked why 5-7 PSI and the maint man said that a "pro" from the city told him it has to be there.
Set pressure down to 2.5 max, leaky valves stopped dripping, building heats better. Could go lower but double sized boiler short cycles already.

nicksxvs

i checked the end switches they all worked.maybe something got fried when it shorted. i'm over my head it's time to call in the pro.those two pigtail thingies i'm guessing ones an upper and the other a lower limit. i probably shouldn't have run the boiler with the zones closed....think i'll lurk awhile have a nice day..

JUGHNE

Pictures would be nice.

JUGHNE

The zone valves in the old school, 2 separate buildings actually, appeared to have end switches. But I learned they are a power open and power close zone valve. Their end switches shut off the drive motor when the shaft has traveled far enough.

Nickssvx

Nickssvx

Jamie Hall

Well, you do have a high limit control -- the clear faced pressuretrol on the right hand pigtail, set at 10 psi. That's a start anyway...

The grey box pressuretrol appears to be set correctly (0.5 psi cutin); if the pressure keeps running too high it may be out of calibration -- or its pigtail clogged. It would probably be useful if the entire assembly holding both pressure controls were taken apart enough to make sure that it and both pigtails were clear into the boiler.

A @JUGHNE said, this boiler -- with its zone valves -- may be set up to maintain a more or less constant pressure at all times when running, controlled by the grey pressuretrol. That's a bit unusual, but not unheard of at all.

The wiring is not much worse than the usual mess; it will be an interesting exercise and well worth the effort to create a wiring diagram for this setup, which will help you figure out what actually does what.

It wouldn't hurt to put a low pressure gauge on the pigtail assembly -- it could be put on the right hand end where there is a plug without too much trouble. Those 0 to 30 psi compound gauges, which you have, are none too reliable -- although they are required by code and insurance types.

nicksxvs

it wouldn't hurt to clean the tubes. i had the boiler running for twenty minutes with two zones open. i should have noted the pressure. maybe during the heating season they just lived with going all the time and during the week flipped the switch and shut it down. the church is a little rundown.i dont know what the electrical components do and i might be able to test them but theres a boiler on the other side of the church that dont want to light. the plumber changed some two inch pipe and i think its full of air.

Zman

In my experience, fried neutrals are usually caused by an incorrect sharing of the neutral. When a neutral is shared by circuits on the same phase, all the smoke comes out.
I would not consider that issue fixed until the neutral is fully investigated.

nicksxvs

it might of overheated or shorted idk. it is a concern.i think a gfci will trip with a shared neutral.my first thought was all the wires are stranded and it was just a bad connection. right now i dont have time to chase the problem down. i have no idea why the burner is being signaled to fire.. have to sleep on it.

Jamie Hall

A GFCI will NOT trip with a faulty shared neutral.. That's not what it's for, and that's not what it does. It may trip if the something is shorted to ground, or if some bozo linked the neutral and ground somewhere out in the building. It happens. Or, obviously, if there is a real ground fault somewhere...

As to stranded wire -- in general, anything 8 gauge and larger will be stranded. 10 gauge and smaller will almost always be solid (there are rare exceptions).

nicksxvs

the pros showed up, they said its normal to maintain a constant pressure when running.your right about gfi's there kind of tempermental about how there wired. what i was thinking was arc faults wont run on a shared neutral like when on a 14-3. Iin town here they run stranded 14-2 or 12-2 with a green thru emt.or ac.

nicksxvs

it was recommended to skim the boiler so i watched some utubes and got a tee and two nipples and i can remove the two limits and screw in my tee, buy how do i control the water inlet there are no valves. it has a condisation tank and it controls the water inlet.

JUGHNE

I assume you mean you have a feeder pump that has a float controlled water fill valve. And have no direct connect to water supply to the boiler.

You can back feed the boiler thru the boiler drain using a double female hose connection (think of a washer hose).
You can get the water from the water heater drain valve or a laundry valve....something with a hose connection.

nicksxvs

oh ok sounds logical, thank you very much. I don't how easy it will be. i think i'll have to attach to one of the drains used for blowdown, and, they have old rusty pipes connected, sounds like a project. maybe the boiler has never been skimmed in 20 years.

JUGHNE

There should be a boiler drain to drain the very bottom of the unit. Maybe on the back side where the water is pumped into the boiler there is valve to connect the inlet water to.

You want the skimming water to come out the side of the boiler just above the water line. There is a plug to the right of the sight glass that might be a good skim port.
(remove only with a socket).

Think of the top oils as small boats, your rising water raises all the boats and they float out of the side tap. Won't work below the water line or out the top.

nicksxvs

i bet there is a drain, i seen the plug it'll take a big socket "if" it will come out. lot less work if it does..

JUGHNE

An 8 point socket made for square heads that is an exact fit and then an impact gun might loosen it.
First several applications of some PB blaster or such.
I hammer on the plugs also between sprays.

You do not want to break the edges off the plug.

nicksxvs

i see its square, i'll have to measure and check hovis auto. i bought a dewalt impact 20 volt, it wont break f150 lugnuts but it's a nice tool. it's small for tight spaces.

JUGHNE

My 1/2" drive 18 volt Milwaukee has always pulled thru.
Hammers a long time but finally did it.

nicksxvs

Milwaukee used to make an excellant sawzall.

Jamie Hall

If you really want to bust things loose... I kind of like my Ingersoll-Rand air driven impact wrench. 3,000 foot pounds torque... but the 18 volt Milwaukee line still seems to be very good quality.

nicksxvs

in the last photo above is a outside temperature device that turns the boiler on when the outside temp hit 52 degrees. When the thermostats, there are 4 zones controlled by 2 thermostats are turned off the boiler continues to come on and off. it cycles between 2 and 4 pounds. Can i turn down the outside temperature device or remove it so the boiler will only come on when the thermostats call for heat? And can the end switches in the zone valves be set to leave the valves partially open to use the heat that is created by the boiler when it cycles when the thermostats are not calling for heat?

nicksxvs

the two thermostats open the four zone valves they are not connected to the boilerthe boiler is cycling i think off the cut in pressuretrol.is controling it. i'm thinking off connecting a relay to the thermostats and the service switch on the side of the boiler. So the relay will open the zones and power the boiler. i turned the differential down a little to far today, the boiler comes on at 1 pound and off at 3lbs.i think 4lbs would be better

Jamie Hall

Say what, @nicksxvs ? The whole idea of having the boiler controlled by a combination of an outdoor temperature signal and a pressure control is so that when a zone valve somewhere opens there is steam available to satisfy that zone. The boiler will only run as much as is needed to maintain system pressure -- very little, if no zones are open, and much more if more zones are open. This is a common enough approach to managing the boiler firing in larger -- often multi-building -- systems.

You could, of course rewire the system so that the boiler only fired when a zone was calling. It would take some time -- if it's a larger boiler, particularly -- before that zone saw any heat, but that may not be a problem in some situations. Do not do it, however, by cutting power to the boiler with the service switch. If there are any pre or post purge controls, or other devices which operate before or after the burners actually fire, doing that will defeat them completely -- and that is not a good idea.

And I completely fail to understand why you would want a zone to get heat when it is not calling for heat. Perhaps I am missing something here. In any event, no you can't modify an end switch on a zone valve to do that. You could install a bypass line, however, which was always open.

nicksxvs

this is a church the boiler is running 24 7, it would not be a problem to wait for the water to get hot. with the zone valves off the steam never leaves the boiler, its just heating the boiler room. the way i want it to work is when the thermostats call for heat the boiler would fire and the zone valves would slowly open. as long as the thermostats are calling for heat the boiler would fire.i dont know if any purge or system would need to be on. it seems a relay would be quick and easy if i have to have a tech do it ok.

Jamie Hall

The boiler should not be running continuously. It should be controlled by the pressure controller, and when there is no demand it should run intermittently -- but certainly not continuously.

A better approach to what you are looking for, which would shorten the time to heat, would be to control the boiler with an aquastat when there is no demand for steam, holding it at some useful temperature -- say 170 or so. This would also reduce corrosion damage in the boiler.

nicksxvs

i guess the relay would have to allow the high limit pressure troll to act as a safety device. i'm going to see if we can get a tech to do something. when this boiler turns off it just shuts down kinda abrupt.

Jamie Hall

The high limit pressuretrol is a safety device. It should be manual reset, and absolutely must be there (depending on local code, it may have to be manual reset). There should also be a much lower limit pressuretrol which cycles the boiler on and off as needed, and can be regarded as a control device.

Similarly there should be two (at least) low water cutouts -- one of which may control an automatic feeder, and the other -- again, manual cutout -- set lower.

I have a feeling that you have a very good setup for what you are trying to do, just as it is, but that the controls for the boiler may have been not thought through all the way, or far more likely modified without understanding the system, at some later date.

nicksxvs

its 8:30 at night and that boilers still running. with the thermostats not calling for heat the zone valves are closed, if it didnt have zone valves the heat would circulate thru the building. i don't know how they set the temperature before zone valves, it's not efficient. "energy crisis"