Boiler not restarting after CH reaches temperature

by **praxyman** » Thu Mar 05, 2009 12:33 pm

Hi,

Hope someone could help. We are having problems with CH in that once it reaches the desired temperature from cold the bolier will shut off but not start up again till over 45 mins later by which time the rads have all gone cold again and all the heat lost.

A new room thermostat has been installed and I have watched the 3-way valve move between all 3 positions which it does correctly as requested by the programmer. Its just that the boiler wont restart again for a considerabler length of time. Pump seems to be working fine and boiler control is set to just under the maximum.

Is this likely to be a problem with the boiler ?

The boiler is a Potterton Neetaheat 10-16 Mark IIF. The system is fully pumped and vented.
All rads have been bled and do heat up fully when boiler is working.

Any help would be much appreciated.

Many thanks

by **gasmick** » Fri Mar 06, 2009 9:34 pm

hi it sounds like the stat has gone out of callibration perhaps needs changing for a new one

by **Steve the gas** » Sat Mar 07, 2009 4:40 am

Hi,

My first thought is its external control problems,-
New stat problem - turn it all the way up
boiler stat prob
All the temp sensors?

by **praxyman** » Mon Mar 09, 2009 8:13 am

Hi,

Thanks for the replies. We did a test with the new room stat on full and the heating intially came on and house heated up fine, then the bolier switched off and didn't restart for over an hour (pump though was still running and 3-way valve was still in correct position for CH only). The rads had cooled right down again prior to boiler restarting and house temp was well below what room stat was set to.
This is also a new Room Thermostat. Old one was a Proscon and the new one is a Drayton RF1.

The boiler dial is set to full but was wondering maybe this is playing up as one of you mentioned.

Is there anything else I could try ? Does this sound like a fault with the boiler itself in some way ?

Thanks