Have altered return flow target temp to 67 degrees hoping this will make a difference. Whats the solution, large house 4 bedroomed, 4 upstairs rads turned off. Boiler running 8 rads and towel rail. System pressurised to 1.2 bar cold. System power flushed and in-line magnetic filter fitted. Superb installation. It just takes forever to to rads to get up to temp. Still only lukewarm after 15 mins, hot at 20 mins, very hot 35-40 mins. This seems wrong and not as good as old noisey kettling boiler.
We have just had our old system boiler replaced with a vaillant ecotec plus 837 and sounds like a similar working operation to ours. At first I was a little concerned,but I was told by our installer that he was told by vaillant that these very latest boilers size the system on start up for about 10 mins, then take temperature to target flow which you set boiler at. So even by setting target flow temperature very high you still get the initial sizing cycle, which ours was about 30-35c temp. These boilers seem to run biased for efficiency as after a while they modulate the boiler burner down and the radiators run more on the side of warm than really hot like the old type boilers. You also get better efficiency as at lower temperature the boiler condenses better. You will also find you get a more constant temperature in your home rather than over shoots. I was concerned at first, shame there was no info/explanation in user manual as people do need to know that this is normal operation. We are used to ours now, took a month and by the way these boilers can make a creaking noise but was told this normal expansion/ contraction but annoying when sited in bedroom cupboard. Best of luck!
SOURCE: Vaillant boiler no heating or hot water
refere to manual check for override switch loss of pressure no problem re-pressurise and check for leak top of rad valve good place to start
SOURCE: boiler overheating
the problem there a relay stuck or thermostat bring on the pump & you can lower your high limit aquastat!! also the flow valves can bypass hot hot water risers time to put in a seperate water heater domestic coil are not energy efficient !!!! aquastat high limit set @ 180f deg low limit set @ 140f deg!!!
good luck!!! tim
SOURCE: vaillant eco tec pro 28 every time cold tap is
try reducing water pressure to cold tap and see what happens
785 views
Usually answered in minutes!
Colin, Your information was very helpful and re-assurring, and it does make sense. Like you I wonder why nobody informs the customer of this energy efficient boilers workings. Many thanks.
×