new house erratic hot water

[someonelse]

Two issues: 1) quantity of hot water created/stored in cylinder 2) erratic delivery of hot water to shower (Aquilisa).

Honeywell L641A 1039 cylinder stat
Baxi Solo 2 50 PF gas boiler
Aqalisa Dream DCV

1) my last house I could press 'extra hour' every few days and heat the entire cylinder. That day water very hot so mixed wth some cold had nice shower, Day 2 no cold water added, shower still hot. Day 3 shower was warm but OK in summer. I never set the hot water timer, just used 'extra hour'. Also only used hot water for the shower.

New house I tried the same but only get 1 days shower from the tank. Discovered the cylinder stat was set to 50, but increasing it to 60 (dificut as the stat is very old/stiff) made no difference. In fact if anything water is colder.

Testing the stat it seems to work and turn the boiler on/off as the stat is turned up/down (though there's a significant delay), but when turned down whle the boiler goes off the pump continues to run and I can still feel water running through the pipes.

Also just noticed (today) the boiler temp is set at the min (see photo). Is that normal? My last house had an oil boiler that had to be set at max to get the rads hot.

2) sometimes even after heating the tank the water from the aquilisa is just warm, even with the aquilisa temp control at max. Reading the instructions it says the small lever on the bottom of the temp control is a 'stop button... to allow for a warmer setting', but this button does not move or do anything.

Q is my problem basically with the cylinder/stat/boiler, or with the Aquilisa?
Q might changing the cylinder stat help?
Q: should an hour be enough to heat the whole tank?
Q am I expecting too much for water to stay hot in the tank?

 

[terryplumb]

Boiler stat on low is economic,but will limit the temperature that the cylinder water gets to.
It's unlikely that one hour would give you a full cylinder of hot water, from cold .
Your shower valve may ,or may not, be in good working order.