flow return temps

[ambrosia]

just got a new attachment for my analyser which measures temperatures of flow and return pipes

now i'm wondering what is a healthy temp difference across a plate heat exchanger?

what temp differences do boilers condense?

when you turn the hot tap on how many degree rise on the flow pipe is down to conduction and how many indicates a divereter valve is letting by?

also any other temp differences that would be handy to know

so far i tried to measure temp difference across my nephews arms, i thought left being slightly closer to the heart might be warmer, but all i found out was putting crocidile clamps on a 2 year olds fingers makes them cry

 

[bewsh]

I spoke to Baxi the other day and the guy reckons you don't want to get any more than 13 degree differential across the plate h/ex.

20 degree flow/return for best condensing (i think)

 

[dancinplumba]

If that 13 is given to the dhw then it isn't going to be very hot dhw. If incoming is 8 then 8 +13=21 ?

 

[Rabbitman]

A good plate transfer I'd be thinking more like 18*c,

 

[dancinplumba]

If looking for 35 rise with 8 incoming, 8+35=43. Boiler flow 62. Return 45. 62-45=17