Minnesota heating system is defined by long, harsh winters that start in October and can occasionally run all the way into late May. That’s two thirds of the year! Your heating system needs to be prepared to keep you warm regardless of the temperature outside. The most common type of heating system is forced air heat, which uses a furnace and ductwork to deliver heat around your home. Some homeowners use a hot water boiler instead, which generates heat through baseboard heating elements. There are things a homeowner can perform on their own time to prepare their system for winter.


Forced air heating systems have air filters that need to be changed regularly to ensure safe and consistent operation. There are many different filter types that can be used, like pleated, foam, spun glass, media and electronic just to name a few. For disposable filters—the most common type—there are different MERV ratings, and this should be taken into account. MERV stands for minimum efficiency reporting value, and measures how effectively the filter removes particles as air passes through it. The higher the rating, the more effective it is.

What most people don’t realize is that these filters should be changed more frequently than what the packaging often recommends. As your filter collects dust and other debris, your heating is working harder than it needs to. This puts additional strain on key components and can even result in safety concerns. We recommend changing one-inch filters every month. If you use four-inch filters, get them checked after 3-4 months and replaced by no more than 6. While each house is different depending on how many people and pets live there, these general guidelines seem to work the best on average.

Drain Lines

There are two types of forced air furnaces, condensing and non-condensing. Condensing furnaces are also called high-efficiency furnaces. They have a condensate trap and drain line system to remove any water produced in the furnace during the heating cycle. These condensate traps need to be cleaned out and the drain line cleaned prior to the start of the heating season. The trap is often found inside the furnace, behind either the upper or lower door. These can be difficult to remove and put back in.

The drain line is attached to the condensate trap. Once it’s removed, it can be cleaned either by washing it out or by using compressed air to force foreign substances out.


Unfortunately, there isn’t much a homeowner can do to prepare their boiler. To ensure it’s ready for the upcoming heating season, professional expertise is best. Like forced air furnaces, there are both condensing “high-efficiency” boilers as well as non-condensing models. The condensing boilers also use the same type of drain system, with a condensate trap and drain line.

One thing homeowners can do to prepare is make sure the boiler’s internal pressure is between 15-18 psi during operation, and that the water is the correct temperature. Most boilers will have a fill valve for adding water if the pressure drops below 15 psi. Boilers also have relief valves that automatically open if the pressure reaches more than 30 psi. We recommend keeping the boiler at or below 18 psi to allow room for expansion. This prevents the relief valve from opening and purging water from the boiler.


Most forced air furnace systems come with a whole house humidifier attached. The humidifier pad should be changed at the start of the heating season and checked at around the halfway mark, typically in December/January. Humidifiers also have drain lines that should be cleaned, once at the beginning of the heating season and a second time in the middle.

Heating Maintenance from Ditter

All heating systems benefit from annual furnace maintenance as long as it’s completed by a licensed contractor. Professional maintenance consists of:

  • cleaning the condensate traps and drain lines,
  • cleaning the burners and combustion chamber
  • visual inspection of heating chamber
  • cleaning the flame-sensing safety system
  • checking gas pressures at the manifold
  • checking combustion and co levels
  • checking all wiring and safety circuits
  • verifying ignitor condition
  • checking all motor bearings and amp draw
  • checking sequence of operation and fan-timing circuit
  • checking air flow and heat rise across the heat exchanger
  • checking the vent system for leaks and deterioration

Ditter Cooling & Heating offers a yearly maintenance program for both heating and air conditioning equipment. For details, get in touch with our staff today. We’re available online or over the phone at 763-200-5055.