boulter oil economy combi.....dhw ....no control

[wilhelm]

hi , maybe oilman can help if youve ever come across this.
boulter economy combi 130k btu, 1998, oil c2.

basically the dhw stat on panel does not alter water temp, which is very hot, tried a new stat....(the priority stat)still the same, the burner comes on immediately , even when stat turned right down , so its getting a call for heat from somewhere.
the plate exchanger is ok, electrics off, hot tap on....tons of cold water through it.

in anyones experience is it the microswitch? or diverter valve?

 

[oilman]

Combi boilers are complete heating systems in a box, they take a methodical approach to diagnose a problem without resorting to changing bits from left to right. (Which is why I get calls from other service engineers ) It is not possible to diagnose accurately without detailed information, but for a start you could check the flow switch operation. You should be able to find all the diagnostic information you need from the manual If you don't have one, request one from: [email protected], making sure you give them the serial number.

 

[wilhelm]

thanks oilman,
I think half the problem is the manual very poorly written and low on real technical detail, this is an early combi, no flow switch, a diaphragm with a microswitch underneath..which i suspect. it also does not have a heatbank, from what i can see. looking at the wiring diagram, the m/switch is all it could be. I just wanted someone to hold my hand before i decided Ill have to keep ordering parts etc etc you know the score
I will post the answer...if i ever sort it, cos its semi interesting.
must get a life....

 

[oilman]

Ill have to keep ordering parts etc etc you know the score

Don't order any more parts, if you can cope with circuit diagrams, you should be able to work through it to diagnose the fault. I'll do a bit of research today.

 

[wilhelm]

cheers oilman, fortunately i had an easy day today, so took some time to "think" instead of rush
checked out m/switch..fortunately it was of michael mouse technology(which i can understand) and both worked ok, so only thing it can be is dhw stat which is thermal reset @ 85 c , so the priority stat on front panel does not seem to alter dhw temp, say it does according to manual, hmmmm i wonder why they dont make em like this anymore...
if youve got manual, there is a functional electrical drawing, so when plunger extends from diverter, it goes norm open , power straight through thermal re-set, to burner, so really this errr piece of ...equipment has not really got any control mind you i did not check temp of water scientifically, maybe it is 85c ah well, im gonna try another stat, and then call it a day

 

[wilhelm]

ok to put "closure" on this, if youre a sad tw@t like me, it may be intrestin or not
anyway, this is a first generation combi, no heatbank, the water to heat dhw comes straight from water jacket,..ie 85c there is no seperate supply(heatbank) for dhw,as in modern combis... so the answer is......like it or lump it.
it can be controlled by central heating stat on boiler, but then obviously your central heating "energy" is down then,
ah well.......there you go.

obvious really.......makes me wonder what the "designer" had in mind??

 

[oilman]

.......what the "designer" had in mind.......

Was a brief from the marketing department.

Only someone living alone, or a nutter, wants a combi.

 

[peter anderson]

oilman wrote:

"Only someone living alone, or a nutter, wants a combi."


I live in a two bedroom flat with my wife oilman (I don't mean that oilman is my wife). Do you recommend me to buy an ordinary boiler rather than a combi? My friend has had a Vokera combi for 6 years with no repairs needed.

Pete

 

[oilman]

Biggest problem with a combi is supply of hot water when the boiler doesn't work. You can see on this forum how often gas and or combi boilers feature, (and how seldom oil). Flow rate is another thing to check before fitting one, but your circumstances may be ok for a combi.

I still wouldnt have one as they are more difficult to maintain than separates. Have you thought about electric?, The maintenance savings can more than pay for the gas servicing and repair costs.

 

[wilhelm]

obviously im refering to oil combis, and in the instance of this particuliar boiler, the design is flawed.
but speaking only for oil combis,(no experience of gas) they are a pain when they go wrong, a lot of stuff crammed into a small area