Knowledge base
In short
An ageing plate heat exchanger can often be kept in service with replacement gaskets or a few new plates, can sometimes be extended when the duty grows, and is replaced as a whole when repair no longer makes sense. The supplier needs the nameplate details, the condition and the new duty to say which of the three applies.
Plate heat exchangers are built to be serviced, and many of them work for decades. Sooner or later an owner has to decide what to do with an old unit: renew the gaskets, replace damaged plates, add capacity or fit a new exchanger altogether. This guide explains in plain words how that decision is usually made and what a buyer should tell a supplier, without figures or part lists.
Why Old Units Are Often Kept
A plate heat exchanger sits in the middle of a circuit, with pipework, supports and controls built around it. Taking it out means draining, cutting and refitting, and sometimes a stop of the whole plant. If the frame and most of the plates are still sound, renewing the wearing parts is usually the quickest and cheapest way to restore the original performance.
That is why a clear picture of the unit as it stands today matters more than its age. Two exchangers of the same year can be in very different condition depending on the liquids they carried and the care they received.
Replacement Gaskets And Spare Plates
The sealing parts are the first to wear in a gasketed exchanger. They harden and lose their grip over the years, and a leak at the edge is the usual sign that they are due. A new set restores tightness, and it is best done together with a cleaning, since the unit is open anyway.
Individual plates can be replaced when some are damaged, cracked or worn through by corrosion. The new plates must match the old ones in pattern and fit, which is why the nameplate details and a photograph of the plate are so helpful. A few spare plates and a set of gaskets kept in store are inexpensive insurance for a plant that cannot wait for a delivery.
Extending An Existing Exchanger
Plant duties grow: an engine is upgraded, a hall is added or a process is run harder. In a gasketed frame it is sometimes possible to add plates and recover capacity without changing the frame, provided the frame has room and the pumps and pipework can accept the new flow.
This is not always possible, and an extension can also shift the balance between pressure drop and temperature approach. For that reason the extension is checked against the whole circuit and not only against the exchanger itself.
When To Replace The Whole Unit
Replacement is the sensible choice when the frame is damaged, when plates are corroded across the unit, when the duty has changed far beyond the original design or when the type itself no longer suits the liquids. A new exchanger can be selected for today's conditions and often lands in the same footprint with the same connections, so that the pipework stays as it is.
TECS Engineering designs and delivers plate heat exchanger solutions for engine, power plant and industrial cooling circuits; send the nameplate details, the condition of the unit and the new duty, and the engineering team will answer.
In Short
- Many old plate heat exchangers are worth keeping in service
- Replacement gaskets restore tightness and are best fitted with a cleaning
- Damaged plates can be replaced if the new ones match the old
- Extra plates can sometimes raise capacity in the same frame
- An extension is checked against the whole circuit, not the exchanger alone
- Replace the unit when the frame or most plates are beyond repair
What To Send With An Enquiry
- The nameplate details and photographs of the unit and of a plate
- The liquids carried and the age and history of the unit
- The fault or symptom, such as a leak or lost performance
- The present duty and any change planned
- The connections and the space around the unit
- Whether a repair, an extension or a new unit is wanted
Questions We Are Often Asked
When do the gaskets of a plate heat exchanger need replacing?
Usually when they harden with age or when a leak appears at the plate edges. It is best done together with a cleaning of the opened unit.
Can single plates be replaced?
Yes, if the new plates match the pattern and fit of the old ones. Nameplate details and a photograph of a plate help the supplier find the right match.
Can an old exchanger be given more capacity?
Sometimes. A gasketed frame with room can take extra plates, but the pumps, the pipework and the whole circuit have to accept the change.
When is replacing the whole unit better than repair?
When the frame is damaged, corrosion has spread across the plates, the duty has changed far beyond the original or the type no longer suits the liquids.
What should I send for a spare part or retrofit enquiry?
The nameplate details, photographs, the liquids, the fault or the new duty, and the space available. The engineering team then advises which route fits.
Contact Us
Send us the heat duty, the fluid temperatures and flow rates, the ambient conditions and the installation limits. We answer with a design proposal - or write to us on WhatsApp.
