Oil Boiler help (used for both steam and hot water )

lakefruit

Hi Guys

I have a 10 years(roughly) old oil boiler used for both steam heating (one pipe) and hot water. Starting last week I noticed the boiler water level has been steadily rising in a rapid pace. For a 12 hours period, the water level increases from level at green arrow to where red arrow is. I checked auto water feeder, it wasn't on during burning cycle.

What problem this might be caused by? I have scheduled a service check next week from oil company who has been serviced the boiler for the past 3 years. Can you guys give me some ideas on what has happen and what I have to do?

Thanks a lot,

Jamie Hall

Two possibilities, and they are both easy to check -- either the autofeeder valve isn't quite closing completely or the domestic hot water coil has a pinhole leak. I can't see from the photos, but there should be another water shutoff valve on the feed to the automatic feeder. Close that, and see if the problem stops happening. If so, you get to replace or repair (more likely replace) the autofeeder. Not difficult, but not free, either. If that doesn't stop the problem, there should be a valve on the feed line to the domestic hot water coil. Shut that off, but leave a hot water faucet cracked open somewhere. If that stops the problem, you have a leak in the coil. Which is not, usually, a simple repair...

lakefruit

Thanks, Jamie. Let me try what you have suggested.

If domestic hot water coil has a pinhole, is Boiler replacement my only choice?

I do plan to replace it with gas Boiler in the next several years.

Jamie Hall

On the boiler replacement... noooo…. not always. It depends a lot on whether you can remove the existing coil without damage, and find and have installed a replacement. Sometimes these things cooperate, and it isn't that much of a hassle. Sometimes... not so much. Or, of course, you could install an indirect tank using hot boiler water, in much the same way as one might install one for a regular hot water system. Or you could install a nice gas water heater, since you plan to get a gas boiler someday. Or... lots of options!

EBEBRATT-Ed

@lakefruit,
I seem to remember that with some Smith boilers the tankless coil is held into the boiler with bolts and nuts making removal very easy (compared with other boilers with drilled & tapped holes and the resultant broken bolts) I think your boiler is a Smith 1100

You can easily find a replacement coil for this boiler Try EVERHOT and their are others who make replacement coils

lchmb

and when you go gas next year, make sure they repipe your boiler in black iron and bring back pictures for us to see!!

lakefruit

Thanks @Jamie Hall and @EBEBRATT-Ed. Indeed tankless coil was bolted to the boiler! I have shut off the feed to auto feeder. I will wait for the service contractor to have a closer look.

EBEBRATT-Ed

I wish all boiler MFG would use the old SMITH method of a cast iron flange. Makes changing a coil a lot better. But they won't cost$$$$

Coat the bolts & nuts with "never seize" for easy removal. Some boilers used brass bolts. Easier to get out and if they broke easier to drill out

lakefruit

@Jamie Hall @EBEBRATT-Ed I read a few more posts on this forum like the post you two have commented back in 2016. This appeared to be a common problem for old boiler.

A different subject though, if I have replacement budget, would you guys recommend to replace current oil boiler by a gas boiler, and add one more zone to existing one pipe steam heating system? Or it is more economical to fix the oil boiler and continue using the simple one pipe steam?

Thanks,

Jamie Hall

That is a very complicated question with no easy answer! First off -- what do you mean by adding one more zone? More steam radiators? Keep in mind that steam boilers are sized to the radiation they feed -- not the house they are heating.

Then on the boiler. Well, a 10 year old boiler is getting on, but isn't ancient. Whether it is less expensive over the long run to fix the old boiler and stay with it for a few more years -- five? ten? or to splash out for a new gas boiler... I wouldn't care to say. You'd have to run the money numbers for yourself, since it depends so much on what -- besides the coil, if it needs it -- needs to be done and what the cost or a whole new install is, and your fuel costs. Just to mention the larger items.

Whatever, keep the steam. If you add more radiation, check the size of the boiler to make sure it is correct. But keep steam!

lakefruit

@Jamie Hall Thanks. I agree with you on keeping steam. I've read through Holohan's book and I really like the simplicity of one pipe system, However I have to say it is very difficult to even the heat distribution across multiple rooms(on two different floors) by just adjusting vent air valve in each room under the constraint of single thermostat. How do you guys resolve this problem?

nicholas bonham-carter

In my 3 floor, 55 radiator building, I have the Honeywell VisionPro thermostat with remote sensor, sensing the temperature of a 2nd floor bedroom on the north end of the building. It has three wall exposure and so looses heat faster than other parts of the building.
I have put in a lot of main vents, so the supply piping will fill first, before steam begins to rise into the radiators. This make sure that all radiators receive steam at the same time. Setting a constant temperature, with no setbacks helps as well.—NBC

Jamie Hall

As @nicholas bonham-carter says, it's in the main venting. The mains have to be very thoroughly vented. It's unlikely in your situation that the risers need venting -- they aren't that big -- but until you get the mains well vented radiator venting just isn't going to be able to control things.

lakefruit

I shut off feed to auto feeder. The water level still rises. Looks like I have to get tankless coil replaced.

HVACNUT

I would consider replacing the mixing valve as well.
Are you sure the boiler is only ten years old?