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.

Mark

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!

Given the pump ought to be almost silent, who cares?

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?

No, the diverter will make a audible click when switching - but I would
not describe it as a "bang". There is little difference in its
activation sound from the boiler being in standby or CH mode IME at the
time of the HW demand.

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?

Air where exactly? Coming out the hot tap?


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
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| John Rumm - john(at)internode(dot)co(dot)uk |
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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

Ed Sirett wrote:
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/GasFittingStandards0

Thanks for relying.

My programmable stat is a Danfoss Randall TP5000. It actually turns the
boiler on 6 times an hour when heat is required, some times for only 30
seconds to top up the temperature of the radiators.

John Rumm wrote:
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!

Given the pump ought to be almost silent, who cares?

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?

No, the diverter will make a audible click when switching - but I would
not describe it as a "bang". There is little difference in its
activation sound from the boiler being in standby or CH mode IME at the
time of the HW demand.

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?

Air where exactly? Coming out the hot tap?


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Hi John,

1) The pump ain't silent it rumbles. It's in the kitchen and it's
annoying.

2)When the diverter valve switches over the water is at full flow too
and from the boiler.... so it hits the back of the claosed valve and
bangs - water hammer. The whole central heating system convulses so
it's a bang audable throughout the house. The pump stops when the valve
is changing from DHW to CH but obviously doesn't when changing from CH
to DHW, Ideal aren't interested.

3) The air is in the boiler closed circuit - it clears when the system
switches to CH as it can be heard entering the first rad. When DHW runs
again the air slowly builds up... Again Ideal aren't interested.

Mark

wrote:

1) The pump ain't silent it rumbles. It's in the kitchen and it's
annoying.

In the same room as the boiler I can't hear the pump over the fan of the
boiler. Could there be a fault with the pump?

2)When the diverter valve switches over the water is at full flow too
and from the boiler.... so it hits the back of the claosed valve and
bangs - water hammer. The whole central heating system convulses so
it's a bang audable throughout the house. The pump stops when the valve
is changing from DHW to CH but obviously doesn't when changing from CH
to DHW, Ideal aren't interested.

I must admit to never having listened carefully to exact switchover
sequence on my HE35 to know if it is doing the same as yours. However, I
have never been aware of anything more than the polite "clunk" of the
diverter valve and the speed up in the fan when switching from CH to HW.

3) The air is in the boiler closed circuit - it clears when the system
switches to CH as it can be heard entering the first rad. When DHW runs
again the air slowly builds up... Again Ideal aren't interested.

Is it air or hydrogen? (i.e. does it burn if you try to ignight the gas
as you bleed it from a rad).

If it is air, and you are sure that it is only/still getting into the
system while in HW mode[1], then that would indicate the fault in the
boiler I would have thought, since the primary heating loop is only
running through the main and plate heat exchangers, the pump and the
diversion valve.

If it is hydrogen, then that would indicate a fairly active corrosion
problem. Is there sufficent corrosian inhibitor in the primary circuit?

Is it loosing water - how often do you need to top up the pressure?

[1] Could it be that air is getting in all the time, but you only become
aware of it in HW mode because a slug of it is released in one hit,
rather than being fed in over time?


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/