plate heat exch and diverter

[buckley plumb]

I was wondering is there an 100% way of knowing if a boiler has a diverter or plate problem if the boiler is only giving slightly warmed water to taps).if the gas rate and burner pressure is what expected then obviously its not the thermistor .I am asking as a few have had me puzzled lately.if the plate to plate was blocked or partialy blocked would the boiler force the flow down the diverter damaging that.is there a set 100% way to check - had a biasi where the diverter had come unclipped internaly and this gave same fault as blocked plate.trying to measure temp diff across plate does not work as you can get heat transfer down the flow as the heat backs up .does heat passing into flow on heating when there is a hw demand always a diverter- seen vaillants where just changing the plate stops heat flow into the heating.its this area of fault finding I struggle on . also is it different for vaillant / baxi / glowworm set ups

 

[Ermintrude]

Ecotec same as gloworm. Pre duo tec same as alpha 240

 

[moogwai]

If the boiler is cycling and not dumping down the flow then ive found its normally a blocked plate. Turn the hot water temp right down and see if it takes longer to cycle.

If the boiler is dumping down ive found its usually the diverter letting by.

If boiler not dumping down and not cycling and fireing away normally on hot water but hot water still not hot then ive found the plate is usually scaled up....happens mostly in hard water areas.

If easy enough I usually take off plate and run it under a garden hose and see what happens.....if you get black flakes then you know its getting blocked up.

Sometimes thermisters read ok but can still be a problem!! Suck it and see problem imo.

 

[illloyd3]

manipulate diverter ensure movement and feal where the heat going, to rads diverter - boiler over heat blockage? not sure about 100% but gota be close

 

[diamondgas]

35[SUP]0[/SUP]C rise? Flow cup and thermometer tells you a lot!

If you can, turning off either flow or return boiler iso can help diagnose. If hot water temp rises significantly with iso closed I'd be erring more towards diverter. If it makes little or no change and/or boiler cuts out then p/hex...! Alas it's not an exact science mate 🙂