scaled exhangers

[leinster]

hi.
is there anyway conclusively to tell that a scaled HE is the cause behind DHW poor temprature?? some one has mentioned getting a digital thermometer and doing a thermal survey on the exchanger? but surley a scaled/ defective thermistor would also be the cause of poor dhw temp.any ideas as ive no wish to replace plate exchangers that are actually fine only to find its scaled thermistors?? help

 

[waterworks]

You can tell most times by the difference in temperature of plate heat exchangers by touching them at the top and bottom, if the connections from the main exchanger side are really hot and the connections to domestic are cool this usually means there is a restriction, most plate ex block quite easily and are most times easy to remove to check as are sensors/ thermistors easy to remove and clean.

 

[BigBurner]

If the plate is easy to get at and remove. Remove it and use Fernox DS3 to clean it out. I probably needs a clean anyhow, so something gained. If it is th same after then look at the 3-way valve, thermisters, etc.

 

[Agile]

hi.
but surley a scaled/ defective thermistor would also be the cause of poor dhw temp.any ideas as ive no wish to replace plate exchangers that are actually fine only to find its scaled thermistors?? help

If you thought about it you would realise that the only effect a dirty or scaled sensor is that it would slow down the response time.

However under static conditions it would reach an equilibrium which would be the same as a clean one.

Your problem is a blocked HE and you can get an idea of the temperature difference by touching the pipes with your hands.

Tony

 

[leinster]

great stuff.thanks