Outdoor Boilers

Wondering if anyone has any hints for inspecting an outdoor, solid fuel-fired (coal and wood) boiler. I’m inspecting a small farm next Tuesday which is using one…

More and more of these are popping up in NE PA…If anyone is interested there is a good article in yesterdays USA today (01/16).

Thank You

Scott Coslett

Simply check for clearances to combustibles…

Like inspecting a heating boiler and a big wood stove/furnace all in one. Got to check the thermostat controlled items such as the prmary draft/blower (if installed), water pump and zones if any (they are used to heat multiple buildings in some cases, mostly on farms). Check condition of the firebox/chamber for warping (if steel)/deterioration of firebrick; similar for the steel chimney. Look for type of piping to house, etc and is it properly insulated.

Clearances to combustibles usually aren’t a problem as these are self contained steel units. Clearances to other buildings may be in the specs. Check with state/municipal codes…some are quite strict as to where and how these can be set up. (I researched this topic 1999 when I ran the energy regulations for our province; was quite surprised to see how many regulations there were for wood burning appliances in your country. I always thought the US had less not more regulations than here in Canada!!!)

Don’t know how heat is distributed in the house…could be through a water-to-air plenum mounted heat coil/exchanger in a furnace or HP/AC forced air (most likely) system or could go into hot water baseboards/radiant floors.

Brian -

Thanks for your guidance. The system is question utilizes baseboard hot water in the house. The mechanics of the system do not scare me. The big question I have has to do with the height of the chimney on the unit. The township in which the dwelling is located made the current owner raise the chimney significantly – I don’t know exactly how high – because of air quality issues . I would think this has some effect on how well the fire will burn. I’m sure it voided any warranty.

I’ve gotten all my info about this inspection from the realtor so this should be an interesting one.

Our Office recently inspected one of these units…


The key to inspecting one of these is to identify the unit (if possible) prior to the actual Inspection.

Obtain the appropriate Maintenace & Installation manuals from the manufacturer (.pdfs generally available on-line) so that you can review and be prepared as to the elements that will need to be inspected.

Educate yourself in the Unit Operation so that you can confidently inspect and answer the questions that your Client may have.

On a side note, I am the BCO of a Borough in central PA. We just wrote an ordinance outlawing these boilers.

Alot of other communities are doing the same.

Would you mind explaining why they are being outlawed?

Certainly. Most of these units come with small stacks. The lots in the borough are small and if we allowed them, we could potentially have alot of smoke all over.

When these are not burning at 100%, they smolder, the smoke is terrible then.

Here is a link to our ordinance if you would like to see.


That’s correct! When these units call for increased water tenperature, a damper door opens and the smoldering fire starts to rekindle which causes a LOT of smoke (I had a unit for years). That’s why these things are banned in some areas.

As far as a taller chimney is concerned, make sure it is insulated. An uninsulated chimney will build up creosote much quicker than an insulated chimney.

Hope this helps a little.


Was the reason for the ban strictly from a visible smoke (aesthetic) perspective or do you possess some verifiable documentation with regard to potential health risks?


The units are tested and “meet air standards” as far as the EPA is concerned. We were more concerned with the “sooting” that happens on houses and buildings that are so close to each other. In Bellefonte, it is a very Historical town with the buildings being so close to one another. Much like West Cheater.

There was one outdoor furnace installed before this ordinance was introduced into adoption. Fortunately, it was erected in a large lot, away from other homes, at a local lumber yard.

The nuissance was the largest reason.


The Wood fired Boiler that we last inspected was in a more rural area of Chester County.

I could not imagine using one in a suburban setting such as in the Boro of West Chester. I can understand the concern there.

UPDATE: Borough Council approved the ban.


That was the issue. Although, people seem upset at getting a “freedom” revoked.