AIC Heat Exchangers builds Advanced industrial Components for long lasting use. Our heat exchangers promise reliable operations and best in class performance. But like every piece of machinery, they come with a limited effective life. Regular maintenance can definitely help elongate the life of heat exchangers and improve its efficiency tremendously, but then comes a time when a complete replacement of equipment is needed. In this section we will discuss the warning signs that your heat exchanger needs to be replaced. But before we move to the replacement bit, let us run through the standard repair procedure for a heat exchanger.
Permissible Repairs of Heat Exchangers
A faulty heat exchanger can jeopardize the entire system’s functioning. Therefore, heat exchanges are required to be pressure tested at regular interval. These pressure testing is normally done at 110% of the operating pressure, wherein pressure is applied using the external pump or the system pump after putting a blank at one end. Post application of pressure the system is put on hold and monitored for 10-15 minutes or as prescribed in the manual. No drop in pressure implies the heat exchanger is perfectly alright. However, a pressure drop during the testing indicates a fault in the tubes.
Consequent to the drop in pressure, the heat exchanger should be immediately repaired before putting in service. It can be repaired by the following ways:-
- Identification of leaky tubes. After opening the heat exchanger, the leaky tubes need to be identified either by naked eyes or by using soap solution method. Post identification these tubes are required to be marked.
- Plugging of tubes. If 10% of the total tubes is observed to be leaking, the tubes can be plugged using plugs, thereby ensuring the faulty tubes out of the system.
- Brazing of tubes. If more than 10% of the total tubes is observed to be leaking, then the tubes are either required to be replaced with new tubes or repaired using welding/brazing.
It is to be noted that the heat exchanger should be pressure tested after undertaking any kind of repairs on it.
Warning signs that warrant replacement
The most common reason for replacement of a heat exchanger is damage to its main body. If you notice cracks on the superstructure of the heat exchanger then it needs to be repaired immediately. But it is advisable to replace instead of repair since cracks mean that the body of the equipment is past its life. The presence of carbon monoxide, water on floor, high level of noise and increased vibrations are some of the common signs that indicate crack on the body. Flickering and dancing flame in the furnace after blower has been switched also points at damage to heat exchanger. Get it checked, and if there is irreparable damage, replace it. Since heat exchangers are meant for high temperature and high pressure processes, any suspected damage must be taken seriously.