Flow Temp Rising Too Quickly - Fix?

[Johntheo5]

Thanks pal!

So installing a new one outside boiler will do the job of the possibly seized one inside the boiler?

Do you know how I clear these D4 341 error messages? Pressing reset and holding it etc doesn't get shut of it. So I don't know if it is a current problem or not regarding the temp rising too fast.

Yes, just install your own one.

Don't know how to clear that message.

Does this mean things will cool down more in the house?

Does increasing the time for 2.3b basically achieve the same thing? - forces the boiler to wait longer between firing cycles?

Yes, but once you determine the Highest minimum flowtemperature to get the boiler away in one go then IMO you are better off using option 2.3.C as that should give the shortest recycle time.

The house will cool down more the lower you have to reduce the flowtemperature but remember the rads will still be emitting heat, at a flowtemp of 38C the rads should be be emitting more than half the heat they emit at 53C so not a big deal even if the recycle time is as high as 10 minutes.

 

[John Smith Esq.]

Yes, just install your own one.

Don't know how to clear that message.

Yes, but once you determine the Highest minimum flowtemperature to get the boiler away in one go then IMO you are better off using option 2.3.C as that should give the shortest recycle time.

The house will cool down more the lower you have to reduce the flowtemperature but remember the rads will still be emitting heat, at a flowtemp of 38C the rads should be be emitting more than half the heat they emit at 53C so not a big deal even if the recycle time is as high as 10 minutes.

I've had good advice here, thanks.

Excuse my ignorance, but when you say "get the boiler away in one go" - what exactly does this mean, what is the objective? Is it to have a longer burning cycle without the chopping and changing of stop and start?

 

[Johntheo5]

Excuse my ignorance, but when you say "get the boiler away in one go" - what exactly does this mean, what is the objective? Is it to have a longer burning cycle without the chopping and changing of stop and start?

Yes, exactly, if the flowtemp was very high at refiring then you could have a situation where the boiler would never fire for more than say 30 secs or so, and just repeatedly recycle, then the house would certainly get a lot colder?

 

[dilalio]

So installing a new one outside boiler will do the job of the possibly seized one inside the boiler?

Not really, your boiler acts as an arch in the pipework and will catch air within it.
That's why combis have a built in AAV.

They often leak if system is dirty so regularly get shut down to stop a leak.

Should be checked for correct operation and changed if necessary - they're there for a reason.

 

[Johnytuono]

I've had good advice here, thanks.

Excuse my ignorance, but when you say "get the boiler away in one go" - what exactly does this mean, what is the objective? Is it to have a longer burning cycle without the chopping and changing of stop and start?

The anti cycle time is the total of an on/off cycle and not the time interval between firing.. So, if you had a anti cycle time set to 10 mins and the boiler fired for say 6 mins and then hit FSP (Flow Set Point) + 5 (4 in my case) then it would stay off for at least 4 minutes OR the hysteresis you have set is reached IF it is longer. On the other hand, if it reached the hysteresis drop within the 4 minutes (as in the scenario above), it would just stay off for the 4 minutes (to equal a full cycle of 10 minutes). Another example to try and explain a little more. If the boiler ran for over the anti cycle time of 10 minutes and then hit FSP +5 it would then only stay off until the hysteresis specified was hit, so if the hysteresis was set too low it would/could be off for only a couple of minutes. It's a way of making sure the water cools down enough so that it is not constantly cycling. Hope this helps as it did confuse me at first. I have my anti cycle time set to 10 mins and hysteresis to 7c (as I run a fairly low flow temp therefore the drop takes longer), this at least cools it a little to enable a longer burn on the next fire up ( I am actually thinking of dropping it to 8c). Bear in mind though that the higher the flow temp set the quicker the flow temp will drop when hitting FSP +5. A 70c flow temp for instance will drop 8c quite quickly. I run at 45c to 52c depending on outside temp.