Boilers - Home Heating Steam and Hot Water Systems - Gas boiler question

I was at a friend's house this weekend looking at a door lock and one thing led to another and he asked me about the boiler and if it looks ok..... I said I'd have a look and see if I noticed anything obvious, but wasn't going to touch anything. Ya know that one, lay a finger on it and as soon as something does go wrong then it would be my problem.

I did notice a few things... No air scoop or spirovent or air vent of any kind anywhere in the system, still hooked up the 50+ year old expansion tank for whatever reason, relief valve not piped to the floor and actually aimed right at the face of whoever gets near the boiler, either the aquastat or the boiler thermometer is not reading correctly. That's what I know.

The question is that in the bottom of the burner drawer tray there is a nice thick layer (a good 1 - 1.5 inches) of white and black sandy looking stuff. There's also a noticeable accumulation of the same stuff on top of the burner tubes. What is this stuff? Does it indicate some other kind of problem going on?

Also, he said that the thermocouple takes a dump at least once a year and calls the boiler guy to replace it. The tech was kind enough to leave the pile of old thermocouples on the floor for the record....

Thank you for any input.

I did notice a few things... No air scoop or spirovent or air vent of any kind anywhere in the system, still hooked up the 50+ year old expansion tank for whatever reason,If the tank is that old, it's likely a conventional tank, not a bladder type. No air removal device should be installed with a conventional tank. All the air is directed to the tank, not atmosphere.

The question is that in the bottom of the burner drawer tray there is a nice thick layer (a good 1 - 1.5 inches) of white and black sandy looking stuff. There's also a noticeable accumulation of the same stuff on top of the burner tubes. What is this stuff?Possibly refractory that has crumbled off over the years. You can check the fire box to see if there is refractory still intact.

OK, I see that now. Air from system keeps the air cushion maintained in the expansion tank. Still wonder why the installer reused that old thing instead of just putting in a bladder tank next to the boiler :confused: There is a good 20 feet of piping that was installed to reach the old tank. Oh well.

Still wondering what all the black and white sandy stuff is on and below the burners......

Hmm... crumbling refractory. The boiler is a small Burnham, I don't remember the model. Looked to be a cast iron hx. Think it was 47k btu. It's only about 10yrs old. Replaced when house was renovated.

for whatever reason, relief valve not piped to the floor and actually aimed right at the face of whoever gets near the boiler, either the aquastat or the boiler thermometer is not reading correctly.The relief valve discharge should be piped within a few inches of the floor.

What is the degree difference between the thermometer and the aquastat? Typically, they measure temperature at different elevations in the boiler, so can be different. Also, the aquastat has a deadband, while the thermometer does not.

wonder why the installer reused that old thing instead of just putting in a bladder tank next to the boilerA conventional expansion tank will work fine and last almost forever. Replacing it with a bladder-type tank would cost money, and eventually the bladder will spring a leak - probably on Super Bowl Sunday, with the outside temps frigid.

The length of the pipe to the conventional exp tank shouldn't matter as long as it is sloped upward toward the tank!

The aquastat is located in a T on the outlet of the boiler. The thermometer is a couple of inches to the right of the outlet pipe directly inside the boiler. Aquastat was set for 180. Thermometer was reading 240 and about 18psi when the high limit shut off.

We could hear the air come out of solution and start gurgling in the rads and swooshing through the circulator more and more as it heated up.