Best Of

The hrv or the fan in a can make the most sense. The other appliances that vent outside like the dryer and the exhaust fans won't work well if they are under negative pressure either. The main maintenance to perform on a cast iron boiler is to make sure it is burning properly and that the safeties work. There is little reason to replace an 11 year old boiler unless it is leaking.

They're upselling you. And they might not even fix the problem.

As has been suggested: Fix the negative pressure issue, and inspect the flues. And then fix the boiler. At 11yrs old you could get another 30 out of it easily. That water heater might live another 5-10 years.

On the gauge — the red hand indicates maximum pressure reached. The black hand indicates the actual pressure in the boiler.

When you fill the boiler, you want the black hand to come alive (it may be) and let it come up to about 2 marks above the 10 mark (about 12 psi). That should be ample.

And on the thermostat —those aren't the most sophisticated, not do they hold that close a temperature — but they will last forever. Keep it.

That setup on the tank is to make draining the tank a little easier. You do not need to do my first step from my previous post to drain the expansion tank. Someone else has made it easier. To start with an empty tank all you need to do is place the end of that hose in the floor drain or laundry tub.

1. Make sure valve #2 is closed
2. Open valve #4 and let the water out. Once the water has stopped flowing the pressure gauge on the boiler will be at or close to zero PSI
3. Open valve #1 and let air into the tank. You will hear air gurgling into the tank.
4. After some time the air starts to gurgle into the system, that means the tank is empty and you close all the valves.
5. Now open valve #2 to to add water to fill the system back to the proper pressure.

The two red valves are a relief valve and a pressure reducing valve the pressure reducing valve is also known as the automatic fill valve. It takes the house pressure of 30 to 70 PSI and reduces it to about 12 PSI. if it is working properly some folks leave the manual feed valve open so there is always 12 PSI pressure on the system. That way, if you are not getting any heat from any given radiator, you can just open the radiator vent and let air out. VIOLA »»» HEAT!

I’m not surprised there isn’t an air bleed on tank. You may find a plug but my tank didn’t have have one. To drain it was simple process of closing valve between boiler and tank; attach hose and then drain. Be prepared for it to take a while since it will be sucking air to make up for vacuum created as water drains out.
Once you get it drain, you can open the valve leading to MPT connection to let air in. Just open it a bit so hopefully only air goes in and no water comes out.

Series 10 controls are no longer available new. You may find some available as new old stock on ebay or Craig's List. But that is not necessary, the series 80 controls are interchangeable with series 10 by just eliminating the R terminal and connecting the series 80 terminal marked R to the series 10 terminal marked B. If the calibration is within acceptable limits, then just leave them alone until they don't work.

I would recommend up grading the gas burner and check the chamber , The boiler part ( pot on the stove ) would last another 100 years ….

The series 10 , Replace thermostat and aquastat ……

@Budward. Looking at your gauge, you probably have to fill and vent the radiators. I'm guessing that your burner worked or is working by the normal thermostat and pilot lighting instructions. If the flame is not happening, then go with @mattmia2's suggestion.

As far as getting the water side right Follow these instructions:

To start with, you need an empty expansion tank. To accomplish that we are going to use valve #1 to let air in the tank while water is draining out the bottom of the boiler #3. First thing is to connect a garden hose to the boiler drain valve #3 and put the other end near the floor drain. If you don't have a floor drain, then you will need use a pump or buckets to get the water out of the basement.

After opening the boiler drain, look at the gauge to see the pressure drop to zero. Once you get that done, you can open valve #1 to let air in the tank. You will hear the gurgling at valve #1. Once the tank is empty, You will hear air bubbles gurgle near the pipe that connects the tank to the boiler supply pipe. Now you know the tank is empty. Shut off valve #1 and #3.

Once that is done, you now can open valve #3 to put water pressure back in the boiler. You will watch the gauge while your helper lets the air out of the radiators until they get a small spirt of water in a can, then they will close the radiator vent and move on to the next. You will continue to add water to the boiler making sure the gauge does no go over 18 PSI. But must always have at least 12 PSI on the gauge. Your job is to open and close valve #2 as needed to maintain that pressure.

Any Questions?

You should find someone that understands that type of burner and make sure it is burning properly. In that type of installation the boiler and vent connector and chimney are all one system that affect how the burner burns. You can clock the meter to diagnose your current problem, I suspect either the regulator or the valve have gone bad and it is underfiring but ultimately you need someone good with combustion to look at it.

Also make sure the boiler is full of water.