Need help with Steam boiler

Iconic

Ive been having a problem with my steam boiler or maybe thermostat.. So im a new home owner and recently i bought a older home that has an older gas fed steam boiler that wont fire up so the previous owner didn't give me too much information on it but i can tell they recently installed a newer thermostat nothing fancy but digital.. When i turn the thermostat on the heat and set the temp it doesn't turn the boiler on but if i go down to the boiler and jump the wires to boiler from the thermostat it will fire up and run until it comes up to the set temperature and then it will shut down but will not cycle or turn back on at all unless i go back down to the boiler and jump the wires again.. Everything seems to be running correctly when system is heating up... If anyone needs anymore further information just please let me know...

EdTheHeaterMan

To be clear, You jump the thermostat terminals and the burner starts, then you remove the jumper and the burner continues to operate until the call for heat is satisfied.

In other words you do not leave the jumper in place the whole time the burner is operating.

If that is the case, then you may have to replace the thermostat. or if you have a Millivolt gas valve, You may need to replace the Pilot Generator.

Can you take a picture of the boiler with your phone and post it here. the picture should be from far enough back to see the heater from floor to ceiling and the connecting pipes. Then a picture of the gas control valve from about 2 feet away. it may be on the inside of the heater behind a panel or access door, or it may be on the outside where you can easily see it.

Iconic

you are correct once the burner starts i remove the jumper and it continues to run until it meets set temp and I'm pretty sure it is a millivolt valve.. Yes i will go and take a couple of pictures for you and post them here in a couple of mins.. Thank you for the reply back!

Iconic

Iconic

Where I have circled is were I jumped it at

EdTheHeaterMan

The Pilot generator on a millivolt system can get weak over time and replacing it may provide more power to the gas valve. Another thing that could be the problem is the thermostat. Is your Newer Thermostat rated for Millivolts? The contacts on some thermostats may not be as sensitive at needed for such low voltage operation. What model is your new thermostat?

I think that if you look at the most recent changes (the Thermostat) you will find your answer faster.

How long has the burners worked since you replaced the thermostat? "Well the problem started soon after the thermostat was replaced". Then let's start at the thermostat!

Iconic

the thermostat is rated for millivolts and the thermostat in the picture is the new one they installed

EdTheHeaterMan

Iconic said:

the thermostat is rated for millivolts and the thermostat in the picture is the new one they installed

Who is They? ... better question... Is that the thermostat that is now operating the boiler?

If so then just check all the connections, wire nuts, screw terminals, Spade terminals on the gas valve, every connection on the burner/thermostat/LWCO and Pressuretrol circuit. Sometimes just tightening up a loose connection will solve the problem. If that does not work, and you are up to it, put a new pilot generator on and see if that solves the problem. https://www.supplyhouse.com/White-Rodgers-G01A-502-Mv-Power-Pile-Generator-w-36-Fiberglass-Leads-and-armor-sleeve. If you are not up to it, then call a professional boiler repairman. You are playing with fire... literally... there is a real gas fire in that boiler

Mr. Ed

Iconic

as mention is the post... the people i bought the house from i don't know if they had someone come and do it or if they did it themselves and that is the thermostat that run the boiler but i do know that they used the original wires going to the boiler ... I definitely could change that out even if it doesn't fix the problem it wouldn't hurt to change it out cause who knows how old it is but thank you so much for trying to help me out i really appreciate it..

EdTheHeaterMan

newer thermostat nothing fancy but digital..

reason I asked about the thermostat.
So this is the thermostat that is operating the boiler and it came with the house. Where it came from does not matter. I misunderstood about the thermostat because you made a special mention about it.

Back to your situation. Millivolt is very sensetive to poor electrical connections and extra long wires. That is why I mentioned that you can check all the wire connections. Sometimes just removing the spade connector and replacing it will refresh the connection. remove a wire nit and replace it with the same wire nut can be all that is needed. checking the screw terminal to see if you can turn it just 1/16 of a turn might help. You can do all that without any parts.

If all that fails then get a new pilot generator.

Good Luck with your heater. I Hope this helps

Mr. ED

vhauk

is it possible that your new t-stat needs a c wire?  Many new digital t-stats will not work in a 2 wire system. 

neilc

are the batteries fresh in the thermostat?

EdTheHeaterMan

vhauk said:

is it possible that your new t-stat needs a c wire?  Many new digital t-stats will not work in a 2 wire system. 

Disagree with this.
Millivolt and C wire are not compatible.
If the batteries are good and the thermostat is actually rated for Millivolt usage, (your's is, see the red box above) then the power pilot is getting low on "power generating"

to be clear on "dressing" the connections here are the ones I'm talking about:

And the wire screw terminals at the thermostat also. Anywhere there are wire connections that can develop corrosion over the many years of just sitting there.

Have you ordered your Pilot Generator yet?

pecmsg

That LV connection above the gas valve doesn't look good. Redo it and get wire nuts on it.

I don't think that luxpro is millivolt.

EdTheHeaterMan

pecmsg said:

That LV connection above the gas valve doesn't look good. Redo it and get wire nuts on it.

I don't think that luxpro is millivolt.

Where are you referring to (above the gas valve)? All spade connections on the valve and no other wires above that I can see.
Look at the specification above! It is rated for millivolt

JUGHNE

But is that the same as the one on the HO's wall?

His has all the connections for AC/HP etc.

EdTheHeaterMan

JUGHNE said:

But is that the same as the one on the HO's wall?

His has all the connections for AC/HP etc.

Look closely are the wall plate. There are only 3 of the 9 labeled terminals with actual brass connections for the thermostat to connect to. RH, G and W.

YEP... that is the same thermostat on the wall as the one on the Spec Sheet pictured.

neilc

why is that pressure gage at 10psi ?

and Ptrol is set up high, someone has aggravated the scale indicator,
dial the trol down using the screw on top of the cover,
inside differential wheel sets to 1
and,
when was pigtail serviced last ?

do we really know what's holding this thing from restarting ?

Chris_L

You can find just about everything you need to know about millivolt gas valves here:
https://heatinghelp.com/assets/documents/Procedures-for-Troubleshooting-Powerpile-Systems2.pdf

As others have said, it sounds like you either have a weak powerpile or a bad connections somewhere. It takes more voltage to open the gas valve than to keep in open. So by jumping it out you are eliminating the voltage drop across the thermostat and other switches in the circuit. You then get enough voltage at the valve to open it, and even after removing the jumper there is enough to keep the valve open.

You need a voltmeter to do some tests. With the boiler off and the pilot on, you should see at least 500 mV or more across the powerpile. With the boiler running (and jumper removed) look for more than 100 mV. If not, see the troubleshooting link above.

Before replacing the power pile, you might try cleaning the tip that sits in the pilot flame. Use a scotch brite pad or similar. And then test the voltages again.

Chris_L

Correction to my previous post:
That 100 mV minimum is between the thermostat out and the powerpile. The voltage across the powerpile terminals should be about 300 mV with the boiler running.

EdTheHeaterMan

neilc said:

...do we really know what's holding this thing from restarting ?

No, the Home owner is not a professional control system trouble shooter. He just mentioned that when he does a temporary jumper to eliminate the thermostat circuit. (what @109A_5 would call a short circuit) then removes the jumper and the burner (gas valve) stays on. The problem is insufficient voltage to open the valve but enough to maintain the open valve.
@ChrisJ understands this! look at his link

Only 4 Reasons for that:
1. Old and/or inefficient pilot generator. (replace the pilot generator)
2. Poor/loose/corroded connection somewhere in the thermostat circuit. (repair the bad connection)
3. A control or switch is defective and has a bad set of contacts. (this is found by a professional repair tech or by doing the Jumper thing at each control to see if that control is the culprit)
4. Gas valve is beginning to fail. (replace the gas valve)

I like to check the least expensive failure first. Checking the wiring connections is free.
Next replace the pilot generator. If that does not solve the problem, then
Replace the Gas valve.

Now if you get to replacing the gas valve, and that does not solve the problem, then you did not do steps #1 or #2 correctly.

I'm betting on the Pilot Generator. I'll give 3 to one odds on that

JUGHNE

Yup ED, I see you are right....3 connections.

Long Beach Ed

Ed, you couldn't be more right in my book.

EdTheHeaterMan

You got to use your head in the big stuff!

Iconic

Ok so I tried jumping it at the thermostat and it wouldn’t fire up so I traced the thermostat wires all the way down and it goes into this.. do you happen to know what that is Honeywell is the company who makes it because I think the problem is something with that..

Long Beach Ed

A transformer and relay.

Iconic

that's what i thought it was, could that possibly be the culprit? Maybe the relay in it?

EdTheHeaterMan

So your thermostat does not need to be Millivolt compatible. The thermostat operates the RA832 relay. That is 24 Volts. Try this test. When there is a call for heat does the relay in the click when you turn the knife switch next to it off and on? If you hear the click and you see the relay move, then we know the RA832 is working.

Next test. The next time the burner does not fire during a call for heat, do the jumper test at the X X terminals on the RA823 control and see if the burner starts. If it does, then the RA832 contacts are defective and we need to address that.. If the jumper test on the X X does not operate the burner, then the RA832 relay is not the source of the problem.

Jamie Hall

Allow me to add that if the burner fires or even the relay clicks when you jumper T to T? If so, go back up to the thermostat and on the base jumper W1 and Rh. Now does anything work? If so, the problem is something about the thermostat. If not, the problem is in the wires.

vhauk

Some…..some digital thermostats use the “c” wire to power the tstat itself. If the system has a relay that starts the cycle, isolating the tstat from the burner control loop, then you can run a digi stat on the batteries. But take my Becket oil burner for example. Most digital tstat will not work with this type of system. Sorry for the confusion.