Boiler Question

TheFew

TheFew

TheFew

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Joined
25 Nov 2017
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352
Greetings,

I was hoping to sanity check the behavior of my boiler with you fine folks.

I have a Worcester green star 40cdi conventional boiler. The boiler is in Eco mode and set to a temperature of 50deg c.

The central heating is switched to off and the hot water is set to come on for 1 hour each day.

So in this condition the boiler seems to be firing every two or three minutes for around 10 seconds ( which is somewhat tedious to listed to at night).

Should the boiler be firing to keep itself at 50 deg c and ready for action? Or should the boiler remain silent and inactive I until there is an actual demand on it (e.g. a request to heat water)?

I can't help but feel that its current behavior is not quiet right...

Thanks
 
So the hot water is in a tank I presume. I have a Worcester combi but no tank .the water is on demand and it never fires unless the hot water taps /shower is on, as you mention and it's also on eco mode at 60c.
 
Mine seems to do the same thing. I have the hot water set to come on for an hour 2 times a day.

However it comes on randomly and goes off randomly. I think the control board is faulty.

Electronics all fail given time. My boiler is around 20 years old. So something has become faulty.

Likely the same thing with yours.
 
50 degrees isnt that warm for the boiler to be running at 65-70 would be more like it. Your probably finding that its running, getting the loop of water up to 50 and then the tank isn't soaking the heat away fast enough so the return water is already up to temp when it comes back to he boiler hence it doesn't need to keep heating it. What temp is your tank set to? because they are normally set to 55-60 and the boiler needs to have a flow hotter then the tank or it will just keep cycling.

My tank holds heat for around two days if it isnt used so I leave the hot water on all the time. It will only heat the tank once the internal temp drops anyway, which is normally after everyone has had baths/showers in the morning.
 
Dandle said:
Your probably finding that its running, getting the loop of water up to 50 and then the tank isn't soaking the heat away fast enough so the return water is already up to temp when it comes back to he boiler hence it doesn't need to keep heating it.
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Hi, I'm not sure I follow, does the boiler aim to keep the loop of water at 50deg even when the controller is not asking for the water to be heated?

Also how would I find out what the tank temperature is set to?

Thanks
 
If you boiler is set to 50 degrees and you demand heating or hot water for your tank then the hottest the boiler will heat your water will be 50 degrees. Now if you tank is set to say 55 degrees then it will never get up to temperature as the boiler is only supplying hot water at 50 degrees. So in effective once the tank is at 50 the hot water loop will be up to temperature the boiler won't heat anymore but the system will keep running as the tank will be telling it it's not hot yet(up to 55).

There are things like weather compensators which vary the temperature of the water loop depending on the outside temperature to make the systems more efficient but again they will never go above the max temp set on the boiler.
 
Ah thanks makes sense. But in this condition would the system still keep running once the hive controller is no longer asking the boiler to heat the tank?
 
TheFew said:
Also how would I find out what the tank temperature is set to?
Click to expand...
Is there not a dial on the side of the water tank?

There is on ours, it's not the same make but it ancient which I don't mind as there are less parts to go wrong as my plumber pointed out.

50 degrees is a bit low for water, the WHO recommend 60 degress to prevent Legionella, although that's a pretty conservative 'safe' temp really.
 
TheFew said:
Ah thanks makes sense. But in this condition would the system still keep running once the hive controller is no longer asking the boiler to heat the tank?
Click to expand...

No if the hive is set to not heat then the boiler should turn off until it tells it it's time to heat either hot water or heating.

The tank temperature is most likely set on a dial on the tank. As adidan said above .
 
Thanks. That is my issue. When no demand on the boiler it keeps cycling on and off :-(

Finally found the temperature dial on the tank. It is set to around 55deg. Never knew that dial was there!!
 
TheFew said:
Thanks. That is my issue. When no demand on the boiler it keeps cycling on and off :-(

Finally found the temperature dial on the tank. It is set to around 55deg. Never knew that dial was there!!
Click to expand...


stick the boiler temp dial to around 20% less than the highest it can go.

stick hot water tank to 60C.
 
Thanks to all for the pointers and the advice.

I think I have found the issue. With the CH and HW set to off, the motorised valve for the HW was still in the on position. Whilst the motorised value is working OK, the metal valve it operates seems to be stuck open.

Some WD40 and abuse by pliers later, I am waiting to see if it is fixed.

I presume it seized because the boiler has been switched off since april..

Thanks
 
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