Header Tank Overflowing

LittleGarry

Hi Folks, I have a query on an issue that I have been having every now and again. Basically I have a 30KW boiler stove, coupled with an oil boiler and solar panels on the roof. Independently of each other they all work fine. Where I have an issue is when the oil boiler comes on to heat the water tank after either:

a) The fire has been on in winter and has kept the water relatively warm (say overnight) and the oil kicks in the next morning to bring the tank up to the prescribed temp (55C).

b) It's been a fairly warm day and the solar panel has part heated the water in the tank - to say anything above 30C - then the oil is boosted for an hour to heat the water for a bath etc.

When the water is not heated from anything other than base room temperature I am getting a flow of warm water back up into the small header tank in the attic which subsequently drains out the overflow at the side of the house.

System works fine if the fire has not been on or solar panel hasn't "pre-heated" the water to any great extent. It is almost like the tank is overheating I never hear the bubbling etc and overflow can start when water in tank is only 40C+. I am at a loss!

Any advice, pointers would be greatly appreciated.

Dtp1979

Before you address the problem
At hand, first I’d find out why your stove isn’t heating the water in your cylinder to at least 60 in winter and second, ESPECIALLY in this weather, why your solar hasn’t got your hot water at 60, from top to bottom.

LittleGarry

Dtp1979 wrote: »

Before you address the problem
At hand, first I’d find out why your stove isn’t heating the water in your cylinder to at least 60 in winter and second, ESPECIALLY in this weather, why your solar hasn’t got your hot water at 60, from top to bottom.

This generally happens first thing in the morning so if the stove has been on it has died down in the small hours hence the overnight drop in tank temp - we boost it for an hour first thing in the morning with the oil before showermageddon. Same story with the solar - endless hot water during the day / evening but often needs a boost in early morning.

Dtp1979

LittleGarry wrote: »

This generally happens first thing in the morning so if the stove has been on it has died down in the small hours hence the overnight drop in tank temp - we boost it for an hour first thing in the morning with the oil before showermageddon. Same story with the solar - endless hot water during the day / evening but often needs a boost in early morning.

That’s the thing though, it shouldn’t need a boost the next morning. If it’s at 60 at night, what is it in the morning?

LittleGarry

Dtp1979 wrote: »

That’s the thing though, it shouldn’t need a boost the next morning. If it’s at 60 at night, what is it in the morning?

Never really checked, but it is not warm enough for more than one shower - I'd imagine it would be mid 30's before we start drawing it off. Surely there shouldn't be an issue with boosting it with oil back up to full temp in any case (without a fountain out the side of the house!).

Dtp1979

LittleGarry wrote: »

Never really checked, but it is not warm enough for more than one shower - I'd imagine it would be mid 30's before we start drawing it off. Surely there shouldn't be an issue with boosting it with oil back up to full temp in any case (without a fountain out the side of the house!).

The fountain outside could be related. If the water is 60 at bedtime then it should be close to 60 by 7am so there’s something seriously wrong with your system.

LittleGarry

Dtp1979 wrote: »

The fountain outside could be related. If the water is 60 at bedtime then it should be close to 60 by 7am so there’s something seriously wrong with your system.

It seems, based on the above comments, that my issues could be serious / complex and I need to get someone with a good knowledge of this stuff to have a look.

Could anyone recommend a good plumber / heating engineer around the north Wicklow area that would know their way around Oil / Solar / Solid fuel combined system?

Please feel free to PM details if it is against the rules to post them here. Thanks for your help!