On Mon, 02 Oct 2006 07:52:20 -0700, mark.horsman wrote:

Hi, I have a Isar HE30 combi boiler and a few things are begining to
get on my nerves.....

1) During CH mode the boiler pump runs on for 4 minutes after the CH
demand has gone. It's a good idea to equalise the water temp around the
system, but not so good if your programmable thermostat turns the
boiler on every 10 minutes to regulate the room temp. The flame only
lights for 30 seconds - then it's 4 minutes of overun. Aaagh!

2) During the overun above if the system recieves a DHW demand - BANG,
the changover valve switches mode whilst the pump is still running.
Hydraulic nightmare!! Anyone else seen this problem?

3) Air, air and more air whilst in DHW mode. 4 months and the system is
still boiling of air! or is it I don't know?

Can anyone cast any info on the above probelms/annoyances.

I think that you may have all or most of the radiator effectively off on
the TRVs and so the boiler quickly heats up and then stops.

Check and review the setting of the TRVs and the Programmable T/stat.



--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html
Gas Fitting Standards Docs he http://www.makewrite.demon.co.uk/GasFittingStandards