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Heat Exchanger Problems

What is a heat exchanger?

A heat exchanger is a device that circulates a liquid or gas through tubing inside it. Depending on whether your HVA unit is set to heating of cooling, the liquid or gas will be warmer or cooler than the ambient temperature. As air blows over the tubes of the heat exchanger, it absorbs the heat or cold from the tubes and changes the temperature on the home. Heat exchanger are found in refrigerators, water boilers and a wide range of appliances. Read below where Experts have given answers to heat exchanger questions.

A check with a carbon monoxide detector found that there is a leak from the seam at the top of the heat exchanger on my Rheem 1603-25 gravity floor furnace. Is it safe to weld it closed?

Carbon Monoxide is a very hazardous gas and welding the a seam closed to stop a leak is not recommended as it could happen again. Replacing the heat exchanger is the safer option.

How do you connect titanium heat exchanger tubing to copper tubing?

The best way of connecting 2 dissimilar metals is with a mechanical connector like a Sharkbite or some other device with a push lock coupling. Please check the rating of the coupling. Most are rated at 240 plus degrees which should be fine as tube temperatures are generally well below this.

The heat exchanger on my 18 year old Teledyne Laars model HH0400C hot water boiler has ruptured and is leaking water all over. I have a quote for $6,000 for replacing the heat exchanger. Would it be better to replace the whole boiler?

Teledyne Laars is a good make and if yours is an old cast iron model, it can last up to 30 years and more. It is always advisable to get more estimates to try for a better price and consider replacing the heat exchanger instead of spending money on a new boiler.

My17 year old Evcon DGRT070AUB (gas forced air) heat exchanger has developed a crack. Is heat exchanger repair advisable or should I buy a new one?

With a 17 year old unit replacement instead of repair is the most advisable. Most heat exchangers come with at least a 20 year warranty, in which case you will only pay the labor cost. Check the plate with the serial number. There is generally a date code there. Once you know that check your warranty to see if it is still valid and if you don’t have the information, contact the company and see if the warranty coverage still exists.

How often should a heat exchanger be descaled?

The frequency of heat exchanger descaling depends on various factors, especially water hardness. In general, it should be done once every 2 to 3 years. A professional service company or Expert should be used to inspect the unit and the scale to determine the best cleaning method. An Expert can also give you an idea of how frequently it should be done based on their knowledge of your local water. You can also consider a water softener if you have hard water. If you have an open loop system, it will use a continuous supply of water untreated water which will lead to much greater scale formation

Whys is there a flame outside the heat exchanger? The burners ignite but the first one has a wide flame that does not completely enter the heat exchanger. I changed the burners, but it made no difference.

The common reason for this happening is a blocked cell in the secondary exchanger. It could be due to water or slime. You could try plugging the top hole tightly and using a tube or hose from an air tank to blow out the blockage. If this does not help it would be best to get a technician to check the unit. Heat exchanger replacement because of this problem is not uncommon.

A defective heat exchanger can affect the efficiency of your HVASC system or your water boilers. Care must be taken when dealing with heat exchanger problems as the tubing inside is easily damaged. It is best to consult your owner’s manual when attempting any heat exchanger repairs and if the help you need is not to be found there, getting the advice of an Expert is the best alternative.
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