I have a gas boiler with a gray box that has switch for either manual or auto. The pilot is a manual start that stays on whether or not the boiler is activated/firing up. This gray box is connected to the electrical power, the thermocouple, & thermostat. What is the function of this box and should it be switched to manual or auto

 

Any numbers on that gray box ?

It should be set to AUTO.

MANUAL will cause the burner to operate when there is no power, allowing some heat into the home during a power failure.

 

No model number, but it is a Honeywell, and inside it indicates certain functions where the wiring is connected such as circulator, thermostat, mv burner, 24v. burner, 120v. line, and there is also some kind of metal dial. Is that the only function (for a power failure)? What is that dial for? The boiler is a GM Delco model no. DGB5P. Thanks.

 

Yes, pretty much... at least I can't think of any other reason for it. Of course if there is a power failure, the circulator pump will not run, but the idea behind being able to fire the burner is to use 'gravity flow' in a power fail situation. In order to use that feature you need a Millivolt Gas Valve, and I suspect that's what you have there.

If you DID need to use it with no power, you would also have to manually open any FLOW CHECK valves that may be installed in the piping... more on this if you are interested, but you would need to provide some pics for us to see if you have them or not. I'm betting that you do.

That's most likely your HIGH LIMIT setting. There is a bulb in the boiler that measures the water temperature and will shut the burner down if it passes the setting on that dial. It should be set to around 180°F ... There are numbers on that dial, yes?

I'm gonna guess and say it's an L8048B aquastat.

 

I thought I read something that the manual setting is for boilers with a standing pilot rather that a system that ignites automatically with an electrical igniter. I may be totally wrong about this so I have some pictures to analyze http://myface.com/user/mmech/gallery (also, more questions):

In pictures 1 & 2 what is the blue green tank for?

Are pictures 5 & 6 a Millivolt Gas Valve?

Is picture 10 the water circulating motor/pump? There was some water dripping from this when I tried to start system and initially opened water valve. I decided not to start system (and closed water valve) due to auto manual switch dilemma. Is this dripping/leaking normal?

Is picture 11 the FLOW CHECK valve you mentioned (also, in picture 2)? What is this for?

Picture 9 shows dial set to 180.

I have a feeling the gray box should be set to manual (it was already set to that when I went to start the system - this is my first time). But, like I said, I could be wrong.

 

The blue-green tank is your 'expansion tank'. There is an 'air bladder' inside that allows the tank to accept the water that expands into it when the boiler is heated.

I don't think so... I can't tell in the pictures, is there a jumper installed from terminals TP to Z in the aquastat box ? [edit: I just realized that if I click on the pic, it gets HUGE, and it does look like a jumper is on TP-Z, correct ?] The two black wires going to the valve from that box, which terminals are they wired to ? B1 and B3 ? [edit: I see from the huge pic that it appears the anwer is Yes, B1 and B3, which would indicate a 24 VAC gas valve] By the way, run that screw on B2 back in and snug it down, don't want it falling out and into the relay. That would be a problem.

IF you have a 24 VAC gas valve, the AUTO/MAN switch will have no effect on operation, and the burner will not function during a power failure condition, and it matters not what position that switch is in.

That aquastat may be an L8148J ...

Yes, and chances are very good that you would be able to replace that pump with a modern one and save a bunch on electricity. The leaking is not normal, but it may subside somewhat after it's run, maybe not, might get worse, it depends on where it's leaking from, and what condition those seals are in. If you are a mechanic you should have no trouble replacing those seals, but I would recommend a new pump... smaller, quieter, less power. I _think_ the new pump should be a bolt-in swap... what's the distance between the flanges ?

No, that is your feed water regulator valve. That valve is intended to add water to your system if the pressure drops below it's setting, typically 12 PSI. That's what the system pressure should be at a minimum when the boiler is cold.

Is there a pressure gauge on the boiler ? If so, does it appear to be functional ? If it appears functional, what is the reading ?

Your system NEEDS a good cleaning. Those cast iron burners should lift off of the tubes, the tubes should lift and slide off the gas jets. Be careful of the pilot assembly when/if you do this. Be sure to shut off power and gas if you do any work inside. I'm willing to bet that you have significant rust and scale in the flue passes, which should be brushed out. I wouldn't doubt if it's nearly plugged with rust... does the flame 'roll out' the front when it's burning ?

I sincerely hope that you have Carbon Monoxide detectors installed in the home... one in each bedroom and one in the main living area.

One of the pics appears as if there is water on the floor. Is that what dripped from the circulator pump ? Or from another known source ? I guess what I'm asking is, the boiler isn't leaking is it ?

Is that grille on the front of the boiler as packed with dust as it appears ? Clean that.

There is a pressure relief valve on the top of the boiler that appears very old. That should be replaced as a 'maintenance item'. If it opens for any reason, it will most likely not close and continue to leak.

It seems that the adjustments on the burners themselves are all caddywompus. Describe the flame you see when the burners are lit. Some air gates are all the way open, some all the way closed, some in the middle. You need to have them properly adjusted... I would recommend a technician with combustion equipment to take a look-see ...

I personally would not fire this system up until it was thouroughly 'gone over'. It absolutely MUST be properly serviced. Sorry to tell you this, but I would 'red tag' it myself.

 

Wow... there are a lot more problems than I figured. Those are very good points. I added picture 12 to the picture gallery which is the pressure gauge/ water temp gauge. This was taken with the system not running so I'm not sure it means much. I'll have to take a closer look and further analyze your response. Thank you much!

 

If that gauge IS functional, then it appears that you have ZERO pressure in the boiler. Do not try to run it that way. You need to know first if the gauge is accurate, if it IS accurate, then you need to determine why there is no pressure in the system.

If there is no pressure in the system, there is a good chance that there is not enough water in the system. If you try to fire it, you run the risk of damaging the boiler due to low water, and increased risk of fire due to overheated system...

In "Boiler 2" there is a red handle valve to the right of the feed water regulator. Is that valve open, or closed ?

Is the valve on top of the expansion tank open ? It should be.

Since you apparently have zero PSI in the boiler right now, it would be a good time to check the air charge in the expansion tank. In the center of the bottom of the tank, there should be a 'schrader' (tire) valve. Put an accurate tire gauge on that valve. You should have 12 PSI of AIR inside the tank. There should be NO WATER come out of that tire valve. If you get water out, the tank is defective and must be replaced. If you get no water, but the pressure is less than 12 PSI use a small compressor (or a hand pump, ugh!) to add air until you have 12 PSI ...

Then, if the red handle valve is closed, open it and watch the pressure gauge on the boiler. The black needle should rise up to meet the red needle, and stay there. Check the whole system for leaks. (you already know that the circulator leaks). If the pressure continues to rise much past the red needle, that regulator valve is either bad or out of adjustment. If this happens, close the red valve !

Yeah, there's a bit of work to do ... but, assuming that the system is watertight (except for the circ) I don't see any reason why the other issues can't be at least remedied to a point where you can run the boiler.

 

I think I'll have a technician take a look and I will review all your points with him and make observations like you suggested. This is a great help!!!

 

Please let us know the outcome !

 

I tested the water pressure per your last post and the gauge didn't quite meet the red needle (at 15) but made it to 11 and stayed there. Is this reasonable?

Before that I tested the expansion tank and it has 12psi (no leaks).

I have yet to give the technician the go ahead, but plan to shortly.

 

Yes, 11 is fine... I assume that it went up to that pressure when you opened the feed water valve ?

You might want to close that feed water valve and watch the pressure for a few days and make sure that it doesn't go back down. If it _does_ go back down that would indicate that you have a leak somewhere in the system. Look for joints that are corroded and green crud on them. Those are leaks... they might not look wet, but they are leaks never the less.

It's important that you checked the expansion tank when there is ZERO pressure in the boiler. If there was pressure in the boiler, you won't get an accurate reading.

Let us know what the tech says...

 

I have added some pictures (mmech’s Gallery) which should help with the following. I had a technician take care of the main problems and perhaps you can tell me if there are still any red flag issues.

The pump was replaced and the water pressure is steady at 15 psi, just slightly past the red needle. I haven't seen any leaks.

It doesn't look like the inside was cleaned. I did clean the front grille already and was wondering if I could just vacuum the inside. The flame isn't rolling out the front and doesn't seem to be affected by not being clean inside.

I have some more pictures of the pressure relief valve and was wondering if you still think it needs to be replaced.

The burners do not look like they were adjusted but the flame looks consistent and even. Can you tell from the pictures?

The system has been working fine for the last two weeks. The technician said that the boiler would probably need to be replaced in about one or two years. Do you think he's right about this? Thanks.

 

That hole they cut way back when to make room for the pump ... that's funny ... but it works, right ?

Yes, you can vacuum ... what I would have liked to see cleaned though is the heat exchanger area ... the flue passages above the burners ... I bet there's TONS of big old rust flakes clogging up them passages... ready to fall out on top of the burners ...

Which by the way, one of your pictures it appears that the burners aren't seated properly ... see how the one on the left is sitting flat, and the others are sitting higher in the rear ?

I don't see how the tech can predict the future like that ... for all he knows, that thing could keep crankin' another 5 (or more!) ... not saying it's efficient or anything, just that it _could_ keep working ...

Did the tech actually TEST the combustion ? Did he give you a piece of paper with the CO2 O2 CO etc ?

Do you have CO detectors installed in the home ?

One wouldn't expect to see the air shutters every which way but loose ... each burner is going to require almost the same air setting as the next ... no, he didn't do anything but change the pump ... I bet he didn't even look ...

Just lit it and ran ...

 

That's a pretty cool 'night shot' of the flame ...

see them orange things that look like "Close Encounters" mother ship landing ? that's the rust flakes that should have been brushed out glowing red hot ...

Oh, the pressure relief ... did the tech test it ? Did he open it, and let it run for a few secs and then snap it shut and look to make sure it didn't drip ?

If it hasn't been opened in a while, DON'T do it now ... it most likely WILL continue to drip.
If it's more than five years old, replace it as a matter of course.

When the system was drained to replace the pump was the perfect time to put on a new valve. They cost about $20 and should have been done as preventative maintenance...

 

In "Before Repair 3" the burners appear to be seated correctly.

So, perhaps he DID remove the burners ... to do look a 'little' cleaner ...