Category: Heating

Heat Exchanger Failure # 4 – Firing Rate.

How can firing rate affect heat exchanger longevity? If the firing rate is too low, its that same as having low return air temperatures (RAT). Condensation will form, mix with the flue gas and cause corrosion. A high firing rate

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Heat Exchanger Failure #3 – Air Flow.

How can air flow cause a heat exchanger to fail? Too much airflow causes the heat exchanger to run cool causing condensation to form inside, and if you read the previous articles you know what that means.   (If you

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Nothing says winter has arrived like a failed heat exchanger…- Part 2; the RAT.

How does low RAT kill a heat exchanger? It cools the heat exchanger, in-turn causing the flue gas temperature to drop below its dew point.

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Nothing says winter has arrived like a failed heat exchanger…

Unfortunately heat exchangers are like everything else in our industry; few die of natural cause, most are murdered.

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Heat Pump Reversing Valve 101

  The reversing valve; the second most confusing part of a heat pump (Yes, the defrost board still holds first place for the most confusing part) So, what’s the confusion about heat pump reversing valves? The confusion is understandable; a

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Heat Exchanger Failure #3 – Low RAT.

In part 2 we told you that over-sizing is the number one killer of gas heat exchangers, so what’s number two? The RAT! No, not the four legged, scurrying around vacant warehouse type. RAT as in Return-Air-Temperature, or more specifically,

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Flame Rectification: Grounding

Heating season is here, breakout the thermal underwear, dust off the heating tools, and brush up on heating system troubleshooting. Tis the season for 3am no heat calls. Oh, joy… Every year more ancient furnaces and boilers are replaced, and

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Heating High Limit Trip Diagnostics

This is likely the most common “no heat” call culprit; The tripped high limit. For such a common symptom, it is one of the most misdiagnosed problems. There are a zillion ways technicians choose to correct it, and most of

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Heat Pump Defrost Board

We looked at the basic concept of how a heat pump operates. We reviewed the defrost cycle. Now we’re going to take a look at the brain of the heat pump; the defrost board. Defrost boards are chock full of

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Heat Pump Defrost

There are two types of defrost control. First, there’s the really old electro-mechanical style made up of line-voltage relays, snap-acting temperature sensors and timer motors. We’re not going to talk about these because this stuff is old. Really old. Pittsburgh

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