I hear ya about the rusting problem, so I'm on the look out for a HX, my british gas neighbour uses one for his hot tub and is looking out for me.
We started filling pool about 11-30am and I started putting all the pipes and pump together, had a slight problem with pump positioning, it wouldn't suck from the boiler end so had to place it at the pool end but after an hour filling we started adding heat, after 20 -30 mins it looked promising as water was slowly warming even with the cold still being added along with cold rain water.
After another good hour or so of filling, it was about half way full, we stopped adding cold water then as we knew we wouldn't have time to fill it completely and heat it to temp, then it soon started warming and by about 2pm it was warm enough that we jumped in.
By 3pm it was warmer than the BBB temp and was lovely, so I turned the boiler down to halfway, by 4pm it was toasty warm, good enough for a bath, by 5pm I switched the boiler to minimum as it was getting too hot for me and we had steam coming from the pool. (will try and upload Lynda's video later)
It was still warming (so warm that I had to sit as upright and out of the water as possible to allow rain and wind to keep me cool) until we got out at about 6-30 -7pm, absolutely marvelous, these times are approximate, but near enough to get an idea of its performance, obviously with a full pool it will take longer to heat to temp but it got so hot that I think cycling on the minimum setting it will keep a full pool well toasty.
It was a good test with outside temps being quite cool and cold rain hitting the surface, so on a warm sunny day it should perform even better.
Lynda and I wouldn't dream of being in a bath for 4 hours but having cold rain on ya back (and big cold drops from the tree if you were that side of the pool) and then ducking into hot water was bliss, our thoughts turned to hot tubbing in winter with snow/frost to plunge into and dark starry skies to look at!
We are well chuffed!
Massive thanks to all you guys!
