Believe it or not, the summer can be harder on your boiler when it is shut down. But it does not have to be if done right

Portage and Main have a procedure that they publish for their customer to use when shutting the Outdoor Wood Boiler ( see below).

Let me explain the theory on why you should follow this procedure you complete your heating season

Once the boiler cools, fill up your boiler to full with additional chemical

When it is heating your home, the water is around 85 deg C (185F) contains almost no oxygen (3.5 ppm) and with the added chemical and a full boiler essentially the oxygen is taken out by the chemicals and rusting is prevented. So when a boiler cools down the level in the boiler will drop 20-30% thus allowing air to come into the water jacket and start rusting. The chemical is in the water and not in the air so it therefore becomes ineffective at dealing with the void at the top of the boiler. (Air = rust),,,,,, so the outcome is try and minimize the headspace in the boiler and fill the boiler with water,,, no air = no rust

Ash is basic in nature and can cause rusting with the minerals, so removing them from the boiler at the end of the season is critical
Creosote is acid and can cause rusting as well and making sure that you scrub down the inside of the boiler is critical as well.
Send a sample to the manufacturer to ensure the rust inhibitor is working to its full potential.

Shut Down Procedure

  1. Prior to starting your shut down procedures, collect water samples and send it to Heat Smart Plus Inc. Allow three to four weeks to receive results.
  2. Once the boiler water has cooled down, check all fittings for leaks and repair/replace as required. After shut down procedures are completed, continue to check fittings for leaks monthly. NOTE: Some fittings will only leak when cooled.
  3. Use the cleanout tool provided to scrape out the reverse turn heat exchanger.
    The easiest way to clean the heat exchanger is to open the front heat exchanger door and use the supplied cleaning tool to pull all of the ashes on the right side of the heat exchanger down to the front and then push them up the left side of the heat exchanger and into the heat exchanger opening at the back so that the ashes fall back down into the fire chamber.
  4. Coat the inside of the heat exchanger with light weight oil, it is also recommended to oil the door hinges and latches as well.
  5. Remove all ash and unburned wood from the fire chamber. Do not let ash build up at any time, ash combined with moisture becomes acidic if left for an extended period of time.
  6. Lightly oil the fire chamber metal, avoid getting oil onto refractory cement and bricks.
  7. Remove all ash from the ash collection area, and lightly oil.
  8. Remove the blower fan, clean the screen, cage wheel and air box assembly. Clean and lube the flapper assembly. Inspect and clean the flex hose and replace if necessary.
  9. Check your door gaskets and float – do they need replacing? Best to order then in the spring rather than wait until you need to use the furnace again in the fall.
  10. Make sure the chimney is covered. ( A clean five gallon pail over the chimney works well.)
  11. It is recommended to keep your circulation pump running year round. This will assist in preventing any sediment for settling, and to keep the chemical emulsified in your boiler solution. It will also assist in keeping your pump(s) lubricated to avoid a pump seizure.
  12. Add boiler treatment, if previous water test results ( as listed in point #1) indicated further boiler treatment is required. Use only Portage and Main approved Boiler Treatment, as required by your warranty. Do not mix with other brands of boiler treatment.
  13. Top off the boiler with water so that there is no air space in the water jacket.
  14. At the start of the next heating season, the excess boiler water should be drained off before heating the boiler. It should be kept for use as ” top up” water as it is already treated with boiler treatment for proper pH, Nitrites and conductivity levels.
  15. Consider next heating season’s wood fuel. Burning dry seasoned wood, reduces acidity that in-turn can cause corrosion. Wood can/should be seasoning all spring/summer. Some wood types ie; Oak, require two seasons to season thoroughly.
    Every Portage and Main boiler is an investment. In order to maximize your investment and help ensure the longevity of your boiler, we have the following further recommendations regarding use and maintenance.
    Keep your boiler, fire chamber, heat exchanger and ash collection area clean and dry. Check and clean regularly, even if it is the off season.
    When cleaning your furnace, pay attention to the heat exchanger and area behind the fire chamber liners. If ashes accumulate, once combined with moisture (high levels of humidity during summer months) they become corrosive and accelerate corrosion and cause pitting of the steel.
    Burn dry seasoned wood. Wood is a type of hydrocarbon, common properties of hydrocarbons are; they produce steam, carbon dioxide and heat during combustion. Therefore the drier the wood the less moisture that is created during the combustion process.
    Use proper burn practices, do not let the boiler water get below 150 F during the heating season, due to the dew point corrosion which will happen around 130F.
    If you are concerned about your boiler’s operation or have questions, we encourage you to contact your dealer or distributor. We want your heating experience to be a positive one, and always appreciate the opportunity to assist in any troubleshooting to correct any issues, before they become a problem.